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EFFECTIVE

• Dyspepsia. Oral calcium carbonate is approved by the US Food and Drug Administration (FDA) as an antacid. Details: Taking calcium carbonate orally as an antacid is effective for treating dyspepsia (1843). Calcium carbonate has FDA approval as an antacid.
• Hyperkalemia. Intravenous calcium gluconate is approved by the US Food and Drug Administration (FDA) for preventing hyperkalemia-induced cardiac abnormalities. Details: Administering calcium gluconate intravenously can reverse electrocardiographic changes and arrhythmias induced by hyperkalemia (12946). Intravenous calcium gluconate is FDA-approved for preventing hyperkalemia-induced cardiac abnormalities.
• Hypocalcemia. Oral calcium treats and prevents hypocalcemia. Intravenous calcium is used to treat severe hypocalcemia. Details: Taking calcium orally is effective for treating and preventing hypocalcemia. Intravenous calcium gluconate, acetate, gluceptate, or chloride is effective for severe hypocalcemia or hypocalcemic tetany (12928).
• Kidney failure. Oral calcium carbonate or calcium acetate is used as a phosphate binder during kidney failure. Details: Taking calcium carbonate or calcium acetate orally is effective as a phosphate binder. Calcium acetate (PhosLo) appears to control hyperphosphatemia better than sevelamer (Renagel) (12943,12944,38990). Calcium citrate is not recommended for this purpose because it increases aluminum absorption and does not bind phosphate as efficiently as calcium acetate or calcium carbonate (21631). Some clinical research also shows that taking calcium orally reduces blood pressure in patients with kidney failure (975).

LIKELY EFFECTIVE

• Corticosteroid-induced osteoporosis. Oral calcium in combination with vitamin D prevents bone density loss that occurs during long-term treatment with corticosteroids. Details: Taking calcium in combination with vitamin D as adjunctive therapy seems to be effective for reducing bone mineral density loss in people using corticosteroids long-term (982,1046,1830,1831,1832,4462,4463,4464,4465,4466)(4467,12945,38493). One specific product used in clinical research is Oscal (Marion Merrel Dow Inc.), which contains elemental calcium 500 mg per tablet plus vitamin D 125 IU per tablet (982). Another product used is Oscal 250 + D (SmithKline Beecham Healthcare), which contains elemental calcium 250 mg and vitamin D 125 IU per tablet (1046).
• Hyperparathyroidism. Oral calcium reduces parathyroid hormone levels in patients with secondary hyperparathyroidism due to kidney failure. Details: Taking calcium orally reduces parathyroid hormone levels in patients with kidney failure and secondary hyperparathyroidism (1827,1828,1829,39174,39425). In elderly women, the combination of calcium and vitamin D reverses secondary hyperparathyroidism and reduces hip fracture risk (8818). Also, population research suggests increased calcium intake from the diet and supplements reduces the risk of primary hyperparathyroidism in women. Supplemental intakes of at least 500 mg/day and dietary intakes of approximately 1100 mg/day are considered to be protective (91353).
• Osteoporosis. Adequate calcium intake, from the diet and/or supplements, is recommended for the prevention and treatment of osteoporosis. Details: The Bone Health and Osteoporosis Foundation (BHOF) recommends ensuring adequate calcium intake in line with the recommended dietary allowance (RDA) by age, along with adequate vitamin D intake, for the prevention and treatment of osteoporosis in adults over 50 years of age. Supplementation can be used to augment dietary intake when adequate dietary intake is not feasible (109425). In the US and Canada, foods containing at least 200 mg calcium with less phosphorous content than calcium can be labelled with a health claim regarding the relationship between adequate calcium intake and a reduced risk for osteoporosis (11940,102148). However, calcium supplementation is not recommended specifically for the primary prevention of osteoporosis. The US Preventive Task Force (USPSTF) states that the current evidence is insufficient to assess the balance of benefits and harms of vitamin D and calcium supplementation, alone or in combination, for the primary prevention of fractures in community dwelling adults without osteoporosis (95695). Also, calcium supplements do not seem to be effective for preventing loss of bone mineral density (BMD) during lactation (988), in patients who have had bone marrow transplantation (1817), or in patients who have had renal transplantation (4823,38736,38871). Maximal bone growth occurs in the teenage years, and then BMD in females remains relatively constant until age 30-40. After age 40, bone loss typically occurs at rates of 0.5% to 1% per year. In males, this occurs several decades later. Bone loss is more pronounced if dietary calcium intake is below the RDA, which is the case for many Americans (2571,2578). One meta-analysis of randomized controlled trials in healthy children 7-14 years old shows that fortifying food with calcium 250-1000 mg daily for up to 24 months modestly improves femoral neck BMD, but not hip or spine BMD. However, the included trials did not supplement vitamin D (107232). During the 5 years immediately after menopause, calcium supplementation has very little effect on bone loss (2569,2570,2575,2576). The rapid loss of estrogen causes a high bone resorption rate, which increases serum calcium levels and therefore decreases intestinal absorption of calcium (2570). After this period, the typical rate of bone loss is 2% per year (2572,2576). Taking calcium 1000-1600 mg daily as carbonate, citrate, lactate gluconate, or citrate malate salt decreases this rate by 0.25% to 1% annually (977,979,981,2569,2571,2572,2575,2576,2578,6850)(38978,38980,39064). The greatest reductions (1% or more) are seen in the first 1-2 years of supplementation when bone remodeling foci can be filled (2569,2576). After this period, the differences in rate of loss between supplemented and non-supplemented females are closer to 0.25% per year (2569,2577). A meta-analysis of clinical evidence suggests that there is no additional benefit after 4 years (38980). Small clinical studies have found that continuous calcium supplementation at an average daily dose of 1050 mg, started after menopause and continued for 1.5-4 years, may reduce fracture rates by 26% when compared with no calcium supplementation. The largest of these studies was conducted in nursing home residents who also received daily vitamin D; the benefits of calcium, specifically, are unclear (39386). Some research also suggests that calcium and vitamin D improves primary prevention of osteoporotic fractures in some older individuals with osteoporosis, particularly the elderly and those who are no longer community dwelling (12930,38875,38849,39026,109471). However, not all research is positive. One large clinical trial in elderly adults with a low-trauma fracture show that taking calcium 1000 mg daily with or without vitamin D 800 IU daily for 2-7 years does not reduce the risk of a second fracture when compared with placebo (13073). Another clinical study shows that taking calcium 1000 mg daily plus vitamin D 800 IU daily does not prevent a second fracture in elderly patients, or prevent a first fracture in elderly patients with other risk factors such as low body weight (less than 58 kg, 127.6 pounds), smoking, family history of hip fracture, or fair or poor self-reported health (12929). Also, some exploratory research suggests that supplements may need to be continued indefinitely; in adults over 68 years of age, any effects of 2 years of calcium supplements on BMD appear to be lost within 2 years after discontinuing supplements (6853). Calcium has additive effects when used with other agents such as vitamin D, estrogens, or calcitonin. Whereas calcium alone generally reduces or prevents loss of BMD, combination with other agents can produce small increases in BMD ranging from 0.3% to 3.3% depending on the combination and dosages used (978,980,1836,2570,2571,2572,2576). However, one meta-analysis in healthy adults shows that fortifying foods with calcium 250-1000 mg daily, in conjunction with vitamin D supplementation, for up to 24 months does not improve BMD when compared with control (107232). The full potential of osteoporosis treatments cannot be realized without adequate calcium intake (2569,2570,2571,2572). Advise patients taking agents such as estrogens, calcitonin, bisphosphonates, or raloxifene (Evista) to ensure that their daily calcium intake meets the RDA. Use supplements if necessary. The usefulness of calcium in preventing osteoporosis in males is not as well-studied. Some observational research has found that calcium 870 mg daily is not associated with changes in BMD and bone loss in males (97201). However, clinical evidence suggests that taking calcium 1000 mg daily for 2 years might improve trabecular or cortical bone mass by 2% to 4% (980,8827,8873). Dietary supplementation with calcium and vitamin D seems to moderately reduce bone loss measured in the femoral neck, spine, and total body, and seems to reduce the incidence of nonvertebral fractures in older patients with osteopenia or low BMD (980).
• Premenstrual syndrome (PMS). Adequate calcium intake seems to prevent symptoms of PMS. Details: There seems to be a link between low dietary calcium intake and symptoms of PMS (2004,6847,39007). Taking calcium 1000-1336 mg daily seems to significantly reduce depressed mood, water retention, and pain, especially if daily calcium intake is inadequate (1822,1823,1824,2004,95821). Calcium carbonate 1200 mg daily seems to decrease PMS symptom scores by about 18% when compared with placebo (1822). Increasing dietary calcium intake is also associated with a decreased risk of developing PMS. Consuming an average of 1283 mg of calcium per day from foods is associated with about a 30% lower risk of developing PMS compared with consuming an average of 529 mg daily (13094); however, taking calcium supplements does not appear to be associated with the risk of developing PMS.

POSSIBLY EFFECTIVE

• Colorectal cancer. Oral calcium seems to be beneficial for preventing colorectal cancer, especially in those with adequate vitamin D levels and normal body mass index (BMI). Details: Population studies have found that increased intake of dietary or supplemental calcium is associated with a reduced risk of colorectal cancer and colorectal adenomas (1047,8820,12120,38951,98898,98899). Clinical trials and meta-analyses of clinical research also show that taking calcium supplements 1.2-2 grams daily for up to 4 years can reduce the risk of colorectal adenoma recurrence by up to 29% (970,12118,12950,15267,34596,38718,39042,95817). However, not all research has been positive. Some meta-analyses of clinical research or observational studies suggest that taking calcium does not reduce the risk of familial adenomatous polyposis or colorectal cancer (34596,39042,39349). Other contradictory research suggests that postmenopausal females who take calcium 1000 mg daily plus vitamin D 400 IU daily do not have a reduced risk of developing colorectal cancer (14290); however, this finding may not be reliable due to the high baseline intake of calcium in study participants. The reason for these conflicting findings is not entirely clear. Vitamin D might be an important factor. People with lower than average vitamin D levels do not seem to get any benefit from calcium supplements (12118). Also, one meta-analysis of previous trials suggests that taking calcium 1200 mg daily reduces the risk of colorectal adenomas in people with a normal BMI, but not in those who are overweight or obese (99715). Despite this conflicting evidence, the US Food and Drug Administration (FDA) approved a qualified health claim in 2005 stating that calcium supplements may reduce the risk of colorectal cancer and colorectal adenomas. However, the FDA has determined that there is little scientific evidence to support this claim (102366).
• Fetal bone mineralization. If calcium intakes are low during pregnancy, oral calcium seems to be beneficial for increasing fetal bone density. Details: With low dietary calcium intake (less than 562 mg elemental calcium daily) during pregnancy, calcium supplementation increases fetal bone mineralization and density. However, calcium supplementation does not offer any additional benefit if calcium intakes are adequate (3263,3264).
• Hypertension. Oral calcium seems to reduce blood pressure by a small amount in adults with or without hypertension. However, it is unclear if this reduction is clinically significant. Details: Many clinical trials and observational studies, including a meta-analysis of 18 high-quality clinical trials, show that intake of calcium supplements or dietary calcium modestly reduces systolic blood pressure in patients with or without hypertension, usually around 1-2 mmHg. Calcium seems to be more effective for certain subpopulations of patients, such as those who are salt-sensitive or have low baseline dietary calcium intake (945,972,974,976,984,1818,1819,1820,1821,6852)(13138,14406,38803,39063,39094,39221,113920,113925). However, a large-scale clinical trial in postmenopausal females shows that taking vitamin D (cholecalciferol) 400 IU daily in combination with elemental calcium 1000 mg daily does not lower blood pressure or reduce the risk of developing hypertension (16714). Additionally, a meta-analysis of 8 clinical trials shows that taking calcium in combination with vitamin D for up to 7 years has no effect on blood pressure (98861). The validity of this finding is limited by the poor methodological quality of the included studies. Some observational research suggests that calcium can reduce the risk for hypertension. Population research in females aged 45 years and older suggests that higher intake of calcium from both diet and supplemental sources is linked to a lower risk of developing hypertension when compared to lower calcium intake (14265). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim stating that calcium supplements may reduce the risk of hypertension. However, the FDA has concluded that this claim is based on supporting, rather than conclusive, evidence (102367). Research evaluating the effect of calcium supplementation during pregnancy on the child's blood pressure has yielded conflicting findings. A systematic review of 2 clinical studies and 3 observational studies found that calcium intake during pregnancy is associated with a 1-2 mmHg reduction in the systolic blood pressure of the offspring between the ages of 1-7 years (38852). However, a separate meta-analysis of 3 clinical studies shows that calcium intake during pregnancy does not reduce systolic or diastolic blood pressure in the offspring (113923).
• Osteomalacia. Oral calcium seems to reverse osteomalacia caused by very low calcium intakes. Details: Osteomalacia is commonly caused by vitamin D deficiency; however, very low calcium intake can also lead to osteomalacia in children and adults. Calcium supplementation can reverse osteomalacia caused by calcium deficiency. Along with appropriate vitamin D supplementation, individuals at risk of osteomalacia need sufficient calcium intake (94819).
• Pre-eclampsia. Oral calcium seems to reduce the risk of pre-eclampsia, especially in high-risk individuals and those with low baseline dietary calcium intake. Details: Although there is some conflicting evidence (971,38756), most clinical research shows that taking calcium orally 1-2 grams daily reduces the risk of pre-eclampsia (973,1833,8828,39043,39319,39426,97348,113919). A large clinical trial of 11,000 pregnant individuals in India and Tanzania shows that supplementation with 500 mg daily is similarly effective to 1500 mg daily (113908). Multiple meta-analyses which include 16-30 clinical studies have found that varying doses of calcium supplementation reduce the relative risk of pre-eclampsia by 46% to 51% when compared with placebo (97348,113909,113919). One of these meta-analyses found that for every 19 females treated with calcium, one episode of pre-eclampsia would be avoided (97348). Additionally, one of these meta-analyses found that calcium reduces the relative risk of pre-eclampsia by 51%, regardless of whether it is taken at a dose above or below 1000 mg daily (113919). Some research suggests that calcium supplementation may have a greater effect in individuals at high risk of pre-eclampsia or with low baseline dietary calcium intake, and when taken at greater than or equal to 20 weeks of gestation (15029,38497,97348,99714,113919). However, another meta-analysis of 30 clinical studies found a similar benefit of calcium in both high- and low-risk individuals (113919). A separate meta-analysis of 6 clinical studies conducted in China evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy. This combination was associated with an 80% lower relative risk of pre-eclampsia and an 83% lower relative risk of pre-eclampsia with gestational hypertension when compared with routine care (113913). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim regarding the use of calcium supplements to reduce the risk of pregnancy-induced hypertension and pre-eclampsia. However, due to the limited and conflicting research available at that time, the FDA stated that this outcome was highly unlikely (102366). Since then, large, high-quality clinical research has supported this finding. In fact, in 2016 the World Health Organization (WHO) released a recommendation to prescribe oral calcium 1.5-2 grams daily during pregnancies at high risk of pre-eclampsia if dietary calcium intakes are low (97347).
• Pregnancy-induced hypertension. Oral calcium may reduce the risk of pregnancy-induced hypertension. Details: A meta-analysis of 17 clinical studies shows that calcium supplementation during pregnancy may reduce the relative risk of pregnancy-induced hypertension by 30% when compared with control (113909). A separate meta-analysis of 6 clinical studies conducted in China, which evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy, shows that this combination reduces the relative risk of pregnancy-induced hypertension by 85% when compared with routine care (113913).
• Rickets. Oral calcium seems to reverse rickets caused by very low calcium intakes. Details: Rickets is commonly caused be vitamin D deficiency; however, very low calcium intake can also lead to rickets. Calcium supplementation can reverse rickets caused by calcium deficiency (94819). A small clinical study in children with nutritional rickets shows that taking calcium 500-2000 mg daily for 24 weeks improves radiographically measured rickets caused by calcium deficiency. Rickets seems to improve more rapidly with calcium 1000 mg compared to calcium 500 mg. However, increasing the calcium dose to 2000 mg daily is not more beneficial than calcium 1000 mg daily (98904).
• Tooth retention. Oral calcium with vitamin D seems to help with tooth retention in the elderly population. Details: A clinical trial in the elderly population shows that taking calcium citrate malate 500 mg daily along with vitamin D3 (cholecalciferol) 700 IU daily orally for 3 years reduces the risk of tooth loss by about 52% when compared with placebo (8816).

POSSIBLY INEFFECTIVE

• Breast cancer. Oral calcium, via supplementation or as part of the diet, does not seem to be beneficial for breast cancer prevention. Details: Although some studies disagree (15631,39041,95811,107237,113917), most population research suggests that increased calcium intake is not associated with overall breast cancer risk (15631,16715,98895,107236,107237,113917). However, one meta-analysis of observational studies shows that although higher total calcium intake is not associated with breast cancer risk, higher dietary calcium intake, specifically, may be associated with a slightly reduced risk (113917). Also, some analyses suggest that calcium intake may be associated with the risk for certain breast cancer sub-types. Some subgroup analyses suggest that calcium intake may reduce the risk of breast cancer in postmenopausal, but not pre-menopausal, adults (15631,107237) and that dietary calcium intake may reduce estrogen receptor(ER)-negative breast cancer, but not ER-positive breast cancer (107236). However, most research has not evaluated the effects of calcium supplementation or intake on breast cancer subtypes. The best evidence to date, from a large scale clinical trial (Women's Health Initiative), shows that taking vitamin D (cholecalciferol) 400 IU daily plus calcium 1000 mg daily for 7 years after menopause does not reduce the risk of developing invasive breast cancer at the end of the study and 5 years after the end of the intervention (16715,98895).
• Fractures. Although oral calcium prevents fractures in osteoporosis, most evidence shows that calcium does NOT prevent factures in people who do not have osteoporosis. See Osteoporosis discussion for more information on the use of calcium for this purpose. Details: Robust meta-analyses of mostly large, high-quality clinical studies show that calcium supplementation 500-1600 mg daily for 0.5-7 years with or without vitamin D does not reduce total fractures, hip fractures, vertebral fractures, or non-vertebral fractures in older adults without osteoporosis (95822,112486). A large-scale study in postmenopausal females aged 50-79 years who were enrolled in the Women's Health Initiative (WHI) suggests that calcium 1000 mg plus vitamin D 400 IU daily for 7 years only modestly improves bone mineral density (BMD) and does not significantly reduce fracture risk. This lack of effect may have been due to low adherence to the treatment regimen. In those who were 80% adherent, the combination of calcium plus vitamin D reduced the risk of hip fracture by about 29% (14282). Also, some clinical research shows that taking calcium carbonate 1000 mg and vitamin D 400 IU for 5 years does not attenuate loss of height after menopause when compared with placebo (95810). Additional meta-analyses of clinical and observational evidence suggest that calcium supplementation is not associated with a reduced risk of vertebral or nonvertebral fractures, such as hip fractures (38589,38888,98895). Some other research has suggested that calcium in combination with vitamin D reduces fracture risk in older patients without osteoporosis (980,1836,8818,12930,12933,12952,38849,102145,107235); however, this research is confounded by a number of variables, including the presence of hormonal therapy and differing levels of fracture risk at baseline (1836,8818,95822). Conflicting findings on this topic might also be due to genetic differences in patient populations. A population analysis of the WHI study found that, in older females with the lowest genetic susceptibility to low BMD, taking calcium with vitamin D is associated with a reduction in fracture risk. However, in females with a higher genetic susceptibility to low BMD, there is no association between supplementation and fracture risk. This might be because individuals with a lower susceptibility to low BMD are also more responsive to calcium and vitamin D supplementation (97357). As of April 2018, the U.S. Preventative Services Task Force (USPSTF) concludes that there is insufficient evidence to determine whether supplementing with vitamin D >400 IU daily along with calcium >1000 mg daily is safe and effective for preventing fractures in community dwelling adults without vitamin D deficiency, osteoporosis, or a history of fracture. USPSTF recommends against supplementing with calcium 1000 mg daily or less along with vitamin D 400 IU daily or less for preventing primary fractures in community-dwelling postmenopausal females (95695).
• Obesity. Oral calcium does not seem to improve weight loss in adults or children with overweight or obesity. Details: Observational research has found that adults and children with low calcium intake are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese when compared to people with high calcium intake (12124,12125,12126,12127,14265). Additional observational research has found that increasing calcium intake is associated with weight loss in females; the results in males have been conflicting (12127,15602,15603). Despite these findings from observational research and a few small clinical studies (12128,15397,14438,98905,113918), most clinical research has found that increased calcium intake does not increase weight loss (12052,13138,15396,15399,38985,39004,97356). A meta-analysis of 20 clinical studies shows that daily dietary and supplemental calcium intake that meets the dietary reference intake (DRI) of 1000 mg or more daily does not increase weight loss in overweight individuals or patients with obesity when compared with intake below the DRI (95813). An older meta-analysis of 13 clinical trials also shows that increased dietary and supplemental calcium intake does not increase weight loss (15605).
• Overall mortality. Oral calcium does not seem to reduce overall mortality. Details: While some population research has found that calcium taken in combination with vitamin D in older females is associated with a lower risk of death (97353), most evidence shows that calcium, with or without vitamin D, has no effect on all-cause mortality (93533,97308,113584).

INEFFECTIVE

• Cardiovascular disease (CVD). Oral calcium does not reduce the risk of developing CVD and may actually increase risk in some patients. Details: Clinical research shows that calcium does not decrease CVD risk. Several separate meta-analyses of clinical and population research involving over 50,000 patients show that taking calcium 600-1200 mg daily for up to 7 years does not reduce the risk of CVD-related outcomes, including stroke and myocardial infarction, cardiovascular death, or overall mortality (39018,91350,92994,93533,97308,98902,107231,107233). No association was found between total dietary or supplemental calcium intake with or without vitamin D and the risk of CVD or mortality (91350,93533,97308). In fact, some population and clinical research has found that when calcium is used alone or with vitamin D, there is an INCREASED risk of CVD and coronary heart disease (38077,107233). However, other clinical research disagrees (93533). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of CVD and coronary heart disease by 1.1-1.2 times when compared with control. However, the majority of the included research evaluated postmenopausal females and it is unclear if this finding is applicable to other populations (107233).
• Chemotherapy-induced peripheral neuropathy. Intravenous calcium does not prevent nerve pain in patients given oxaliplatin. Oral calcium has not been evaluated for this purpose. Details: While pooled analyses of cohort studies and randomized controlled trials suggest that calcium and magnesium infusion decreases the incidence of oxaliplatin-induced neurotoxicity, a meta-analysis of only randomized controlled trials shows that the infusion has no effect in preventing neurotoxicity (90028,90029,90031). Additionally, clinical trials show that administering calcium gluconate 1 gram with magnesium sulfate 1 gram intravenously immediately before, or before and after, the administration of a single oxaliplatin cycle (90005), or over the entire 6-cycle course of oxaliplatin, does not improve symptoms of neurotoxicity when compared with placebo (96474).
• Myocardial infarction (MI). Oral calcium does not prevent MI. When taken in the absence of vitamin D, oral calcium may increase the risk of MI. Details: Population research has found that increased dietary intake of calcium is associated with a decreased risk of MI (91350). However, a 2010 meta-analysis of clinical research shows that taking calcium at a dose of at least 500 mg daily is associated with an approximate 30% INCREASE in the risk of MI in patients over the age of 40. According to this analysis, one additional case of MI will occur for every 69 patients that take calcium for 5 years (17482). A more recent meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of MI by 1.2 times when compared with control. However, the majority of the included research studied postmenopausal females and it is unclear if this finding is applicable to other populations (107233) In contrast, other meta-analyses of clinical research have shown that taking calcium for up to 7 years is NOT associated with an increased risk of MI, including a meta-analysis that only included postmenopausal females (93533,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of MI in postmenopausal females (93533). Also, the association between calcium supplementation and MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. It is unclear if oral calcium is beneficial for alcohol use disorder. Details: Preliminary clinical research shows that taking calcium carbonate 800 mg and vitamin D 200 IU orally daily for 14 days modestly reduces alcohol craving scores and withdrawal scores when compared with placebo in adults with alcohol dependence that are undergoing withdrawal. Taking calcium carbonate did not reduce the need for diazepam; however, the study may have been inadequately powered to detect a difference between groups (107234).
• Atherosclerosis. It is unclear if oral calcium is beneficial for atherosclerosis. Details: A population study has found that taking calcium 1.2 grams daily for 3 years has no effect on carotid intima thickness or carotid atherosclerosis incidence. A total calcium intake (dietary and supplemental) of at least 1794 mg daily in older females may be associated with a decreased risk of carotid atherosclerosis when compared with a total calcium intake below 1010 mg daily (97351).
• Autism spectrum disorder. It is unclear if oral calcium during pregnancy is beneficial for reducing the odds of autism spectrum disorder in the offspring. Details: A small observational study found that calcium supplementation during pregnancy is associated with a 52% reduced odds of an autism spectrum disorder in the offspring (98900).
• Brain tumor. It is unclear if dietary calcium intake is associated with risk of brain tumor. Details: A meta-analysis of 4 case-control studies has found that higher dietary calcium intake is associated with a lower odds of brain tumor when compared with lower dietary intake (113922). The validity of this finding is limited by the exploratory nature of the included studies, which analyzed all dietary ingredients for any potential associations.
• Cancer. Oral calcium alone does not seem to prevent cancer. It is unclear if oral calcium with vitamin D is beneficial for preventing cancer. Details: Taking calcium alone does not seem to significantly reduce the risk of cancer (12118,15629). The role of calcium in cancer prevention when taken along with vitamin D is controversial, as conflicting results exist. One clinical trial shows that healthy postmenopausal females who take supplemental calcium 1400-1500 mg daily plus vitamin D3 (cholecalciferol) 1100 IU daily have a 60% lower relative risk for developing cancer of any type. Approximately 25 postmenopausal females would need to take this combination for 4 years to prevent one occurrence of cancer (15629). However, a more recent clinical study shows that healthy postmenopausal females who take supplemental calcium 1500 mg daily plus vitamin D3 (cholecalciferol) 2000 IU daily do not have a reduced risk of cancer at 4 years (93943). Reasons for the disparate results are not entirely clear. The discrepancies do not appear to be related to baseline vitamin D levels or different study populations. It is possible that, given the 10-year time lapse between the two publications, the discrepancies result from differences in cancer detection capability. Also, since cancer risk was a secondary outcome measure in the earlier study and a primary outcome measure in the more recent study, it is possible that the discrepancies result from differences in statistical methodologies. The effect of vitamin D and calcium on cancer risk in males and younger patients is not known. There is also interest in using calcium for reducing the risk of hematological malignancies. An analysis of the Women's Health Initiative study shows that taking calcium 1000 mg daily in combination with vitamin D3 400 IU for up to 10 years is associated with a 20% reduction in the risk of hematologic malignancies when compared with placebo. However, no effect on hematologic malignancy related mortality was seen (97354).
• Depression. It is unclear if oral calcium is beneficial for depression prevention. Details: Population research has found no association between a higher dietary intake of calcium and the risk of depression when compared with a lower dietary intake of calcium (96480).
• Diabetes. It is unclear if dietary calcium intake is associated with type 2 diabetes risk. Details: Some population research has found that a higher intake of calcium from the diet or supplements, alone or in combination with vitamin D, is associated with a lower risk of developing type 2 diabetes when compared with lower calcium intake (14265,16713,96473,113929). One meta-analysis of cohort and cross-sectional studies found that the highest level of dietary calcium intake is associated with an 18% relative reduction in risk of type 2 diabetes when compared with the lowest level of intake. A dose-response analysis suggests that each 300, 600, and 1000 mg per day increase in dietary calcium intake is associated with a 7%, 14%, and 23% reduced risk of type 2 diabetes, respectively (113929). However, population research is often limited by confounding variables. For example, one analysis suggests that any beneficial effect might be influenced by concomitant magnesium intake (96473,113929), while another suggests that any benefit from increased intake may be more pronounced in females, adults aged 50 years or older, and Asian populations (113929). Furthermore, other population research has found that serum calcium levels higher than 9.6 mg/dL are associated with greater risk of developing diabetes in Chinese adults with osteoporosis (95815).
• Dyslipidemia. It is unclear if oral calcium is beneficial for dyslipidemia. Details: One clinical study in adults with mild to moderate hypercholesterolemia shows that adding calcium carbonate 400 mg three times daily to a low-fat diet (American Heart Association Step 1) for 6 weeks reduces low-density lipoprotein (LDL) cholesterol levels by 4% and increases high-density lipoprotein (HDL) cholesterol levels by 4% when compared with the low-fat diet and placebo (2557). In contrast, a clinical study in females with dyslipidemia shows that taking calcium 800 mg daily for 2 years INCREASES total cholesterol levels and carotid intima-media thickness in postmenopausal, but not premenopausal, females when compared with placebo (97350). Calcium supplementation has also been evaluated in combination with vitamin D. A meta-analysis of randomized controlled trials including adults with normolipidemia and dyslipidemia shows that taking calcium 500-2000 mg daily and vitamin D 200-7142 IU daily modestly improves HDL cholesterol and triglyceride levels, but not LDL cholesterol levels, when compared with placebo. Subgroup analyses suggest that calcium and vitamin D supplementation is most beneficial in patients with dyslipidemia at baseline (107227). The relationship between dietary calcium intake and serum lipid levels has also been evaluated in observational research. A meta-analysis of 7-11 observational studies found that dietary calcium intake is not associated with total cholesterol levels, although small differences in individual lipid parameters were identified. Additionally, a meta-analysis of 4-9 observational studies suggests that calcium intake is not associated with the risk of developing hypertriglyceridemia, hypercholesterolemia, or low HDL. A subgroup analysis found that higher calcium intake may be associated with lower triglyceride levels in Asian populations (113927). Overall, these findings are limited by significant heterogeneity and the cross-sectional nature of the included studies.
• Dysmenorrhea. It is unclear if oral calcium is beneficial for reducing pain associated with dysmenorrhea. Details: Clinical research shows that taking calcium carbonate 1000 mg with vitamin D 5000 IU daily for three menstrual cycles does not reduce pain when compared with placebo in patients with primary dysmenorrhea (95821). However, calcium carbonate 1000 mg taken alone seems to reduce pain when compared with placebo.
• Endometrial cancer. It is unclear if oral calcium is beneficial for endometrial cancer prevention. Details: A meta-analysis of population research suggests that calcium supplements may reduce the risk of endometrial cancer, but dietary calcium does not seem to have any effect (38893).
• Exercise-induced muscle damage. It is unclear if oral calcium is beneficial for reducing exercise-induced muscle damage. Details: A very small clinical study in resistance-trained adults shows that taking calcium carbonate 500 mg 4 times daily for 3 weeks does not attenuate exercise-induced muscle damage from bench presses when compared with placebo (113933). This study may have been inadequately powered to detect a difference between groups.
• Fall prevention. It is unclear if oral calcium with vitamin D is beneficial for preventing falls. Details: Research suggests that calcium in combination with vitamin D, but not calcium alone, might prevent falls by decreasing body sway and normalizing systolic blood pressure (6362,11939,39038). Some experts think the combination of calcium and vitamin D may be important (11916). Preliminary clinical research in adults residing in a health care facility shows that taking vitamin D supplements while increasing dietary calcium and protein for 2 years reduces falls by 11% when compared with standard diets. Intervention diets were supplemented with milk, yogurt, and cheese to provide calcium 1142 mg and protein 69 grams daily (107235). There might also be different effects in females compared to males. In one study, females aged 65 years or older who took vitamin D 700 IU plus calcium citrate 500 mg daily over a 3-year period had a 46% lower risk of falling. However, this combination did not decrease falls in males (14291).
• Fluorosis. Oral calcium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Taking calcium orally, in combination with ascorbic acid (vitamin C) and vitamin D, seems to be effective for reducing excessive fluoride levels in children and improving symptoms of fluorosis in children aged 6-12 years (990).
• Heart failure. It is unclear if oral calcium in combination with vitamin D is beneficial for preventing heart failure. Details: Based on a secondary analysis of a large-scale clinical trial (Women's Health Initiative), taking calcium 1000 mg with vitamin D 400 IU daily does not reduce the risk of heart failure in the overall population or in individuals at high risk. However, in a subgroup of postmenopausal females without risk factors for heart failure, calcium and vitamin D supplementation might reduce the risk of developing heart failure by about 37% (97307).
• Lead toxicity. It is unclear if oral calcium is beneficial for reducing blood levels of lead. Details: Lead is mobilized along with calcium from bone during pregnancy and lactation, resulting in increased serum concentrations of lead. One clinical study suggests that calcium supplementation does not significantly decrease these elevated lead concentrations (1586). However, another clinical study suggests that taking calcium reduces blood lead levels by 11% when compared with placebo, with greatest effects observed in those with high baseline levels of lead (38957).
• Lyme disease. Although there is interest in using oral calcium for Lyme disease, there is insufficient reliable information about the clinical effects of calcium for this condition.
• Metabolic syndrome. It is unclear if oral calcium alone or with vitamin D is beneficial for metabolic syndrome prevention. Details: Population research has found that a higher intake of calcium from diet and supplements alone, or in combination with vitamin D, is associated with a lower risk of developing metabolic syndrome when compared with lower calcium intake (14265,16713).
• Nephrotic syndrome. It is unclear if oral calcium with vitamin D is beneficial for preventing nephrotic syndrome. Details: Clinical research shows that taking calcium 500-1000 mg daily for 3 months in combination with vitamin D3 60,000 IU daily or weekly for 4 weeks has no effect on bone mineral density or the risk of relapse in children with steroid-sensitive nephrotic syndrome (97355).
• Nonmelanoma skin cancer. It is unclear if oral calcium is beneficial for preventing keratinocyte carcinomas. Details: In middle aged and older adults recently diagnosed with a colorectal adenoma, clinical research shows that taking calcium 1200 mg daily as calcium carbonate for 3-5 years does not reduce the incidence of keratinocyte cancer when compared with placebo over a median of 8 years. A sub-group analysis shows that taking calcium alone or with vitamin D3 1000 IU daily reduced the risk of invasive cutaneous squamous cell carcinoma by a moderate amount, but had no effect on the risk of basal cell carcinoma (104622).
• Oral mucositis. When used in combination with fluoride treatments, a calcium phosphate mouth rinse seems to prevent and reduce mucositis-related pain in patients undergoing hematopoietic stem cell transplantation (HSCT). Details: A small clinical study in patients undergoing HSCT shows that using a particular mouth rinse (Caphosol, EUSA Pharma) containing calcium phosphate, in combination with fluoride treatments, reduces days of mucositis, the duration of pain, and the dose and days of morphine used when compared with placebo and fluoride treatment (38611).
• Ovarian cancer. It is unclear if oral calcium is beneficial for ovarian cancer prevention. Details: An older meta-analysis of 12 cohort studies found that dietary calcium intake is not associated with a reduced risk of ovarian cancer (38792). However, a more recent pooled analysis of 15 cohort and case-control studies has found that the highest intake of dietary or dairy calcium is associated with a 20% lower risk of ovarian cancer when compared to the lowest intake (97349).
• Postpartum depression. It is unclear if oral calcium is beneficial for reducing postpartum depression risk. Details: Preliminary clinical research shows that taking calcium 2 grams daily beginning at 11-21 weeks gestation reduces depression at 12 weeks postpartum when compared with placebo. However, no benefit is seen at 6 weeks postpartum (39447).
• Pregnancy-related leg cramps. It is unclear if oral calcium is beneficial for preventing leg cramps during pregnancy. Details: A small clinical study shows that taking calcium 1 gram twice daily (as a mixture of salts) for 2 weeks can reduce pregnancy-related leg cramps during the second half of pregnancy when compared with no treatment (2567).
• Prematurity. It is unclear if supplemental calcium is beneficial for the growth and development of preterm infants. Details: A small clinical study in preterm infants consuming human milk shows that supplementation with calcium 45 mg/kg daily and phosphorus 25 mg/kg daily does not affect infant weight, length, head circumference, or risk of osteopenia after 6 weeks when compared with human milk alone (113924). However, the duration and size of this study may have been too limited to detect any difference between groups.
• Preterm labor. It is unclear if oral calcium reduces the risk of preterm labor. Details: A meta-analysis of 10 clinical studies shows that taking calcium supplements during pregnancy does not reduce the risk of preterm labor when compared with placebo (113909). A separate meta-analysis of 7 clinical studies conducted in China, which evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy, shows that this combination reduces the relative risk of preterm labor by 74% when compared with routine care (113913).
• Prostate cancer. It is unclear if oral calcium is beneficial for prostate cancer prevention. Details: Some clinical research shows that taking calcium 1200 mg daily might decrease the risk of developing prostate cancer (14133). However, some epidemiological research suggests that consuming very high doses of calcium, over 2000 mg daily, might actually increase the risk of developing prostate cancer (14134). Some epidemiological research also suggests that doses greater than 1500 mg daily increase the risk of poorly differentiated, clinically advanced, and fatal prostate cancer (14132). Consumption of dairy products has also been weakly linked to a modest increase in risk of prostate cancer (98894). However, contradictory research suggests that there is no association between dietary intake of calcium and overall risk of prostate cancer (14131,14132,104630).
• Stroke. It is unclear if oral calcium is beneficial for stroke prevention. Details: Some population research has found that increasing dietary calcium intake is associated with a decreased risk of ischemic stroke (4822,38678). However, other population research has found that increasing dietary calcium intake is not associated with a decreased risk of stroke (91350). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years does not affect the risk of stroke when compared with control. However, the majority of the included research evaluated postmenopausal females, and it is unclear if this finding is applicable to other populations (107233).
• Vertigo. Oral calcium with vitamin D might reduce positional vertigo; the effect of calcium when used alone is unclear. Details: A large clinical study in adults with recurrent benign paroxysmal positional vertigo shows that taking calcium 500 mg and vitamin D 400 IU twice daily for one year reduces annual recurrence of vertigo by 27% when compared with no treatment. The number needed to treat to prevent vertigo was 3.7 (103681). It is unclear if this benefit is due to vitamin D, calcium, or the combination. More evidence is needed to rate calcium for these uses.

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POSSIBLY EFFECTIVE

• Common cold. Taking echinacea orally while still healthy may help prevent the common cold, but the benefit is probably modest. Echinacea does not seem to have a significant benefit for treating colds that have already developed. Details: Three meta-analyses show a 10% to 58% reduction in the risk of developing a cold when taking various forms of echinacea (17520,17522,95652). A large clinical study shows that adults who use a specific echinacea extract (Echinaforce, A. Vogel Bioforce AG) 0.9 mL three times daily (2400 mg echinacea daily) for 4 months, with an increase to 0.9 mL five times daily (4000 mg echinacea daily) at the first sign of a cold, have 59% fewer cold episodes and 26% fewer days with cold symptoms than those taking placebo (18225). Many smaller studies have shown a non-significant trend toward a prophylactic benefit, but they were likely underpowered to detect a statistically significant difference (3282,6386,17521,95652). Research in adults who are deliberately infected with cold viruses shows that taking echinacea products either does not reduce the incidence of colds, or has a limited effect which is not statistically significant. Products used include E. angustifolia root extract 300 mg three times daily for 7 days before and 5 days after experimental infection (13419), an alcoholic extract of E. purpurea above-ground parts (EchinaGuard, Madaus AG) 2.5 mL three times daily for 7 days before and 7 days after experimental infection (12354), or echinacea 300 mg three times daily for 14 days before and 5 days after experimental infection (8228). These studies are small and have methodological problems. Some small clinical studies have suggested that taking E. purpurea extracts as a tincture or tea to treat the common cold modestly reduces symptom severity and reduces cold duration by a couple of days (6384,10320,10802,12355,14419,20062,111530). Specific products used in these studies include Echinilin by Inovobiologic Inc., and Echinacin and EchinaGuard by Madaus AG (10320,10802,12355,20062). In contrast, higher quality clinical research shows that taking E. purpurea alone or with E. angustifolia does not reduce duration or severity of cold symptoms when compared with placebo (10800,11970,17519,20059). Echinacea has also been evaluated in children. Preliminary clinical research in healthy children 4-12 years old shows that taking a specific E. purpurea product (Echinaforce Junior, A. Vogel) 400 mg three times daily for 4 months reduces the occurrence of cold symptoms, respiratory complications (such as pneumonia and otitis media), and antibiotic prescriptions by 30%, 52%, and 62%, respectively, when compared with vitamin C 50 mg three times daily. Taking echinacea also reduces the average duration of symptoms during respiratory illness by an average of 1.4 days when compared with vitamin C (105719). However, other clinical research in children has found no benefit with a specific E. purpurea product (Echinacin, Madaus AG) (4989,95653).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Anxiety. It is unclear if oral echinacea reduces anxiety. Details: Preliminary clinical research shows that taking a specific E. angustifolia extract (ExtractumPharma ZRT) 40 mg once or twice daily for 7 days reduces anxiety scores on the State-Trait Anxiety Inventory scale when compared with placebo (20064,103233). This extract seems to be more effective in patients with high baseline anxiety scores (103233). A lower dose of 20 mg daily appears to be ineffective (20064). Conversely, a small clinical study in physically healthy adults with mild to moderate anxiety shows that taking the same E. angustifolia extract at doses of 20 or 40 mg twice daily for 6 weeks does not reduce anxiety when compared with placebo (106626).
• Athletic performance. It is unclear if oral echinacea improves athletic performance. Details: Preliminary clinical research in healthy, recreationally active males shows that taking echinacea (Puritan's Pride) 2 grams four times daily for 28 days increases serum erythropoietin levels and maximal oxygen consumption (VO2max) during exercise tests (20066). However, two small clinical studies in endurance trained athletes and in non-athletes with high aerobic fitness show that taking E. purpurea 8 or 16 grams once daily for 35 days in combination with other ingredients (Biomedical Research Lab), or taking E. purpurea (Puritan's Pride) 8 grams daily for 42 days, has no effect on erythropoietin levels, VO2max, or aerobic capacity (95651,101593). A meta-analysis of these and other small clinical trials in trained and recreational athletes shows that taking echinacea 8 grams orally daily for 28-42 days does not improve VO2max, hemoglobin, or erythropoietin levels when compared with placebo (114569). However, this analysis may have been inadequately powered to detect a difference between groups.
• Atopic dermatitis (eczema). Some evidence shows that an echinacea cream may be effective in mild disease, but it has not been compared to conventional treatments such as corticosteroids. Details: Preliminary clinical research in patients with mild atopic dermatitis shows that applying a cream containing echinacea (Linola Plus Cream, Dr. August Wolff GmbH & Co) 2-3 times daily for 12 weeks reduces symptoms such as erythema, edema, pruritus, and dryness when compared with a cream containing birch bark extract (Imlan Crème Pur, Birken AG). However, the echinacea product was no different to the comparator cream at the 4- and 8-week assessments, indicating that it might take up to 12 weeks to show benefit (97499).
• Attention deficit-hyperactivity disorder (ADHD). Although there has been interest in using oral echinacea for ADHD, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Burns. Although there has been interest in using topical echinacea for burns, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral echinacea for CFS, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Coronavirus disease 2019 (COVID-19). It is unclear if oral echinacea is beneficial for preventing or treating COVID-19. Details: A moderate-size open-label clinical study tested the effects of echinacea to prevent or treat respiratory viruses. This study of otherwise healthy adults in Bulgaria shows that taking echinacea extract (Echinaforce, A. Vogel AG) 2400 mg daily for cycles of 2, 2, and 1 months, with a 1-week break between each cycle, does not reduce symptomatic respiratory tract infections, including SARS-CoV-2, or respiratory virus detection overall when compared with usual care. However, echinacea extract does reduce the risk of a positive test for coronaviruses or SARS-CoV-2 by 48% and 63%, respectively. In patients who develop a symptomatic respiratory tract infection, this study also shows that taking the same echinacea extract 4000 mg daily for up to 10 days speeds viral clearance compared with usual care when all virus types were analyzed; however, clearance of SARS-CoV-2 was not improved. Echinacea may also reduce the number of days with a fever, but not other symptoms (111174). The validity of this study is limited by lack of blinding. Further, most patients were unvaccinated against COVID-19; it is unclear whether these results can be extrapolated to vaccinated patients. Echinacea has also been studied for long COVID. A moderate-size clinical trial in adults with recent COVID -19 infection shows that taking a combination product containing echinacea 30 mg, rose hips, zinc, and other ingredients orally daily for 2 months moderately improves fatigue scores when compared with placebo (114570).
• Genital herpes. It is unclear if oral echinacea is beneficial for genital herpes in patients with herpes simplex virus (HSV) type 1 or 2. Details: Some clinical research shows that a specific E. purpurea extract (Echinaforce, A. Vogel Bioforce AG) 800 mg orally twice daily for 6 months does not seem to prevent or reduce the frequency or duration of recurrent genital herpes in patients with herpes simplex virus (HSV) type 1 or 2 (7087).
• Gingivitis. Echinacea, in a mouth rinse or periodontal patch, has only been studied in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that using a mouth rinse containing echinacea, gotu kola, and elderberry (HM-302, Izun Pharmaceuticals) 15 mL three times daily for 14 days might prevent worsening of gingivitis when compared with a placebo rinse, but it produces only minimal improvement in symptoms (20069). Applying a periodontal patch containing echinacea, gotu kola, and elderberry (PerioPatch, Izun Pharmaceuticals) either as a single dose, or three times daily for 1 day then once daily for 2 days seems to reduce some measures of inflammation and gingivitis at some time points, but effects lack consistency (20068,20070).
• Herpes labialis (cold sores). Although there has been interest in using topical echinacea for herpes labialis, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• HIV/AIDS. Although there has been interest in using oral echinacea for HIV/AIDS, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Human papillomavirus (HPV). Oral echinacea has only been studied in combination with other ingredients; its benefit when used alone is unclear. Details: Preliminary clinical research shows that taking a specific combination product containing echinacea, andrographis, grapefruit, papaya, pau d'arco, and cat's claw (Immune Act, Erba Vita SpA) three tablets daily for one month reduces the recurrence of anal condylomata in patients following surgical removal. After one month, the recurrence rate was about 4% in the echinacea group compared with 18% in the control group; after 6 months the recurrence rates were about 7% and 27%, respectively (20073). However, poor study methodology limits the validity of these findings.
• Influenza. Limited data suggest that oral echinacea may improve the response to influenza vaccine, and that a combination product containing echinacea may improve rates of recovery from influenza. Details: Preliminary clinical research shows that a taking a specific echinacea product (Monoselect Echinacea, PharmExtracta) 200 mg orally daily for 15 days, then 100 mg daily for 15 days, followed by 100 mg every other day for 60 days, might improve the response to influenza vaccine in people with chronic bronchitis or asthma (18226). Higher quality research is needed to confirm these results. Taking a specific combination product (Echinaforce Hot Drink, A. Vogel Bioforce AG), containing elderberry juice and extracts of E. purpurea above-ground parts and roots, 5 mL five times daily for 3 days, then three times daily for 7 days, improves rates of recovery and influenza-related respiratory complications similarly to oseltamivir 75 mg twice daily for 5 days (95650). However, due to the lack of a placebo group, it is unclear if both treatments were beneficial or if the outcomes represent the natural progression of influenza.
• Insect bite. It is unclear if topical homeopathy with a gel containing echinacea is beneficial for insect bite treatment. Oral echinacea has not been evaluated for this use. Details: Preliminary clinical research shows that using a homeopathic after-bite gel, containing echinacea, marsh Labrador tea, and stinging nettle, on affected areas does not reduce erythema or itching after a mosquito bite when compared with placebo (89235).
• Lichen planus. It is unclear if oral echinacea is beneficial for patients with this condition. Details: A small clinical study in adults with erosive oral lichen planus in Iran shows that taking a specific echinacea extract tablet (Immustim, Goldaru Corp.) 114 mg three times daily for 35 days decreases pain scores, number of lesions, and symptom severity when compared with placebo. However, all patients also used a mouthwash containing betamethasone, diphenhydramine, nystatin, and aluminum-magnesium suspension three times daily (111173).
• Malaria. Although there has been interest in using oral echinacea for malaria, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Migraine headache. Although there has been interest in using oral echinacea for migraine headache, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Otitis media. Oral echinacea does not seem to reduce the rate of recurrence of otitis media in young children, and may actually increase it. Details: Preliminary clinical research shows that taking a specific liquid extract of echinacea fresh roots and dried mature seeds, 0.5 mL three times daily for 3 days at the first sign of a common cold, followed by 0.25 mL three times daily for 7 days, does not prevent otitis media in children 1-5 years of age with a history of recurrent otitis media. In fact, the risk of an episode of otitis media during the 6 month follow-up seemed to increase by 59% in those taking echinacea when compared with placebo (20063).
• Psoriasis. Although there has been interest in using topical echinacea for psoriasis, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Respiratory tract infections. It is unclear if oral echinacea is beneficial for preventing or treating respiratory tract infections. Details: A large clinical study in adults with respiratory tract infections shows that using echinacea spray or taking echinacea lozenges 16,800 mg daily during days 1-3 and 2240-3360 mg daily afterward for up to 10 days does not improve time to recovery, symptom relief, or number of sick days when compared with echinacea tablets or drops at a prophylactic dose of 2400 mg daily for 10 days. However, the higher dose from days 1-3 is associated with faster viral clearance than the prophylactic dose (111540). The validity of these effects is limited by insufficient blinding and a lack of a placebo group. Additionally, echinacea has been studied for prevention of respiratory tract infections. A meta-analysis of many clinical trials shows that taking echinacea up to 16,800 mg daily, alone or in combination with other products, for up to 17 weeks reduces the risk of respiratory infection and antibiotic prescriptions when compared with control (114568). The validity of this study is limited by heterogenous methods between clinical trials, including population, dose, and outcome definitions and measurements.
• Rheumatoid arthritis (RA). Although there has been interest in using oral echinacea for RA, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Tonsillitis. Oral echinacea has been used with azithromycin to reduce relapses of recurrent tonsillitis in children. A throat spray containing echinacea has also been evaluated for tonsillitis-associated sore throat. It is unclear if echinacea is beneficial for either purpose. Details: Preliminary clinical research in children with recurrent tonsillitis shows that adding echinacea suspension, 250 mg root powder per 5 mL, orally 3 times daily for 10 consecutive days per month for 6 months, to azithromycin 10 mg/kg/day for 6 consecutive days per month for 6 months reduces the number of tonsillitis attacks when compared with azithromycin alone (104127). However, the study was not blinded and the number of tonsillitis episodes in both groups was very low. Other preliminary clinical research shows that applying a throat spray containing sage and echinacea whole plant extract every 2 hours up to 10 times daily for up to 5 consecutive days is as effective as a chlorhexidine-lidocaine spray in patients with sore throat due to acute pharyngitis or tonsillitis (20077).
• Tonsillopharyngitis. Oral echinacea has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized study in patients aged 12-75 years with acute tonsillopharyngitis shows that taking lozenges containing echinacea extract 800 mg and sage extract 5 times daily for 4 days reduces throat pain and tonsillopharyngitis symptoms when compared to baseline, both acutely within 90 minutes and after 4 days of treatment (111530). The validity of these effects is limited by a lack of a comparator group. It is unclear if these effects are due to echinacea, sage, or the combination.
• Upper respiratory tract infection (URTI). It is unclear if oral echinacea is beneficial for preventing or treating URTIs. Details: A moderate-size open-label clinical study tested the effects of echinacea to prevent or treat respiratory viruses. This study of otherwise healthy adults in Bulgaria shows that taking echinacea extract (Echinaforce, A. Vogel AG) 2400 mg daily for cycles of 2, 2, and 1 months, with a 1-week break between each cycle, does not reduce symptomatic respiratory tract infections, including SARS-CoV-2, or respiratory virus detection overall when compared with usual care. However, echinacea extract does reduce the risk of a positive test for coronaviruses or SARS-CoV-2 by 48% and 63%, respectively. In patients who develop a symptomatic respiratory tract infection, this study also shows that taking the same echinacea extract 4000 mg daily for up to 10 days speeds viral clearance compared with usual care when all virus types were analyzed; however, clearance of SARS-CoV-2 was not improved. Echinacea may also reduce the number of days with a fever, but not other symptoms (111174). The validity of this study is limited by lack of blinding. Further, most patients were unvaccinated against COVID-19; it is unclear whether these results can be extrapolated to vaccinated patients. Another large study in adults with URTIs shows that taking a combination product containing echinacea 1100-2200 mg, zinc, and vitamin C (EZC Pak) daily for 5 days reduces time to recovery by 1.4 days but does not reduce symptom severity when compared with placebo (111512). The validity of these effects is severely limited by multiple instances of selection bias. Additionally, it is unclear if these effects are due to echinacea, other ingredients, or the combination.
• Urinary tract infections (UTIs). Although there has been interest in using oral echinacea for UTIs, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Vaginal candidiasis. Although there has been interest in using oral echinacea for vaginal candidiasis, there is insufficient reliable information about the clinical effects of echinacea for this purpose.
• Warts. It is unclear if oral echinacea is beneficial for warts when used alone or in combination with other ingredients. Details: Preliminary clinical research shows that taking echinacea 600 mg orally once daily for up to 3 months does not clear common, plantar, or plain cutaneous warts any more effectively than placebo (20080). Other preliminary clinical research shows that taking an oral supplement containing echinacea with methionine, zinc, probiotics, antioxidants and immunostimulants for 6 months, in addition to using conventional topical therapy to treat cutaneous warts, seems to increase the rate of complete remission from 54% to 86% when compared with conventional therapy alone (20071). It is unclear if these effects are due to echinacea, other ingredients, or the combination.
• Water warts. It is unclear if oral echinacea is beneficial for water warts (molluscum contagiosum). Details: In children who have been successfully treated with curettage for molluscum contagiosum, taking a combination of E. angustifolia and E. purpurea orally daily for 2 months is associated with a relapse rate of about 39%, compared with a rate of 68% in a control group that received no oral treatment (104128). The validity of this finding is limited by the lack of a placebo control. E. angustifolia and E. purpurea were taken in doses of 200 mg each in children under 20 kg and 400 mg each in children over 20 kg. More evidence is needed to rate echinacea for these uses.

(Read more about ECHINACEA)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there has been interest in using topical grapefruit oil for acne, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Asthma. It is unclear if oral grapefruit is beneficial in patients with asthma. Details: There is some evidence that consumption of vitamin C-rich citrus fruits, including grapefruit and others, might improve lung function in people with asthma. Intake of citrus fruits 1-2 times weekly has produced this benefit in some studies (6049,6055,6056). However, other studies have shown no benefit (6057,6058).
• Atherosclerosis. Although there has been interest in using oral grapefruit to treat or prevent atherosclerosis, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Atopic dermatitis (eczema). It is unclear if oral grapefruit seed extract is beneficial in patients with atopic dermatitis. Details: One small, uncontrolled clinical study in patients with atopic dermatitis shows that taking a specific grapefruit seed extract product (ParaMicrocidin, Allergy Research Group) 150 mg three times daily for one month can decrease complaints of constipation, flatulence, and abdominal discomfort, possibly due to changes in intestinal microflora (5866). The validity of these findings is limited by a lack of control group.
• Depression. Although there has been interest in using inhaled grapefruit oil as aromatherapy for depression, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Gingivitis. Although there has been interest in using topical grapefruit oil as a rinse for gingivitis, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Headache. Although there has been interest in using inhaled grapefruit oil as aromatherapy for headache, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Hypercholesterolemia. It is unclear if oral grapefruit is beneficial in patients with hypercholesterolemia. Details: One small clinical study in patients with hypercholesterolemia shows that taking capsules containing grapefruit pectin 5 grams three times daily for 16 weeks decreases total cholesterol by 8% and the ratio of low-density lipoprotein (LDL) to high-density lipoprotein (HDL) cholesterol by 10% when compared to baseline (2216). The validity of these findings is limited by the lack of a comparator group.
• Hypertriglyceridemia. It is unclear if oral grapefruit is beneficial in patients with hypertriglyceridemia. Details: One small clinical study in patients with hypertriglyceridemia that is not well controlled on statin therapy shows that consuming one red or white grapefruit daily for 30 days reduces total cholesterol by 8% to 15.5% and low-density lipoprotein (LDL) cholesterol by 11% to 20% when compared with placebo. In addition, consuming one red, but not one white, grapefruit daily reduces triglyceride levels by 17% when compared with placebo in these patients (53352).
• Intestinal parasite infection. Although there has been interest in using oral grapefruit seed extract for intestinal parasite infections, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Lice. It is unclear if topical grapefruit extract is beneficial in children with head lice. Details: One small clinical study in children aged 2-9 years with head lice shows that applying 50 mL of a specific shampoo containing grapefruit extract (Licatack shampoo) to the hair for 10-20 minutes and then rinsing with water and combing can eliminate adult lice. Applying a second application after 10 days seems to help remove any remaining nits (91417). The validity of these findings is limited by a lack of control group.
• Obesity. While some small studies suggest that oral grapefruit extract, taken in combination with other citrus extracts, may modestly improve weight loss, the effect of oral grapefruit alone is unclear. Details: One small clinical study in obese adults shows that consuming one and a half fresh grapefruits daily for 12 weeks reduces body weight by 1.3 kg when compared with placebo. Also, although drinking 8 ounces of grapefruit juice or taking grapefruit capsules three times daily for 12 weeks did not improve body weight when compared with placebo in the overall study population, a sub-group analysis of obese adults with metabolic syndrome shows that taking grapefruit capsules or drinking grapefruit juice increases weight loss and improves insulin resistance when compared with placebo (53353). Grapefruit has also been evaluated in combination with other citrus ingredients. Two clinical studies shows that taking a specific combination product (Sinetrol, Fytexia) containing sweet orange, blood orange, and grapefruit extracts for 12 weeks can decrease body weight, body fat percentage, and body mass index (BMI) in otherwise healthy overweight adults (95517,95518). In one study, taking this supplement as 450 mg twice daily for 12 weeks reduced body weight by 1 kg and body fat percentage by 6.5% when compared with placebo. Hip circumference, waist circumference, and blood glucose were also reduced when compared with placebo (95518). In another study, taking this same supplement as 700 mg twice daily for 12 weeks reduced body weight by 5.6 kg, body fat percentage by 5%, and BMI by 2% when compared to baseline. Patients taking placebo experienced no significant improvements from baseline (95517). It is not clear if these effects are due to grapefruit extract, other ingredients, or the combination.
• Pharyngitis. Although there has been interest in using topical grapefruit oil as a gargle for pharyngitis, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Psoriasis. Although there has been interest in using oral grapefruit for psoriasis, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Stress. Although there has been interest in using inhaled grapefruit oil as aromatherapy for stress, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Upper respiratory tract infection (URTI). Although there has been interest in using grapefruit oil as aromatherapy for various upper respiratory tract infections, including influenza and the common cold, there is insufficient reliable information about the clinical effects of grapefruit oil for these conditions.
• Vaginal candidiasis. Although there has been interest in using oral and topical grapefruit seed extract for vaginal candidiasis, there is insufficient reliable information about the clinical effects of grapefruit seed extract for this purpose. More evidence is needed to rate grapefruit for these uses.

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INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). Lemon has only been evaluated in combination with quince in a nasal spray for hay fever; its effect when used alone is unclear. Details: A small clinical study in patients with grass pollen allergy shows that using a specific nasal spray (Gencydo, Weleda AG) containing lemon and quince three times daily for 7 days does not improve the symptoms of allergic rhinitis when compared with placebo. In this study, using the nasal spray reduced airway resistance during inspiration at 10 and 20 minutes after pollen exposure, and reduced airway resistance during expiration at 20 minutes after pollen exposure (98826).
• Anxiety. It is unclear if aromatherapy with lemon essential oil reduces anxiety. Details: A small clinical study in first year nursing students in Turkey shows that administering aromatherapy with lemon essential oil for 15 minutes prior to an exam reduces test anxiety scores when compared with control students (110779). However, it is unclear whether any improvements are clinically significant or lead to improved test scores. Lemon oil has also been evaluated in pregnancy. A small clinical trial in Turkey in pregnant adults in active labor shows that administering aromatherapy with lemon oil, 1 drop placed on a cotton ball, every hour until delivery does not reduce anxiety when compared with control (115746).
• Halitosis. Lemon essential oil has only been evaluated in combination with other essential oils; its effect when used alone is unclear. Details: Preliminary research in males with dementia in a long-term care facility shows that cleaning the tongue, gums, and teeth with a solution of lemon, peppermint, and tea tree essential oils twice daily for 7 days improves oral condition, measured on the Korean Oral Assessment Guide scale, increases salivary pH into the normal range, and decreases halitosis score when compared with saline control. On a scale of 0 to 5, the essential oil mixture reduced the halitosis score by 1.24 points, compared with 0.2 points for the control (112957).
• Hypertension. It is unclear if oral lemon is beneficial in patients with high blood pressure. Details: A small, prospective, population study in middle-aged Japanese women has found that increased lemon intake is associated with a modest reduction in systolic, but not diastolic, blood pressure (93471).
• Kidney stones (nephrolithiasis). It is unclear if oral lemon juice is beneficial for recurrent idiopathic calcium oxalate nephrolithiasis. Details: A randomized, controlled trial in patients with recurrent idiopathic calcium oxalate nephrolithiasis shows that taking fresh lemon juice 60 mL orally twice daily for 2 years with a standard diet does not improve the time to stone recurrence when compared with no supplementation. The validity of these findings is limited due to poor patient adherence, which declined from 79% at 6 months, to 68% at 1 year, and 48% at 2 years. When restricted to a 1-year follow-up, stone recurrence occurred in 10% of patients taking lemon juice, compared with 21% of patients in the control group; this difference was statistically significant (107489).
• Labor pain. It is unclear if aromatherapy with lemon oil is beneficial for labor pain. Details: A small clinical trial in Turkey in pregnant adults in active labor shows that administering aromatherapy with lemon oil, 1 drop placed on a cotton ball every hour until delivery, modestly reduces patient-reported pain during the early phase (cervical dilation 5-7 cm) when compared with control (115746). However, clinical significance is unclear, and pain is not reduced during the later phase of active labor (cervical dilation 8-10 cm).
• Meniere disease. Although there is interest in using lemon orally for Meniere disease, there is insufficient reliable information about the clinical effects of lemon for this condition.
• Myocardial infarction (MI). It is unclear if aromatherapy with lemon essential oil is beneficial in patients with acute MI. Details: A small clinical study in hospitalized patients with acute MI shows that administering aromatherapy with lemon essential oil over 3 days moderately reduces systolic blood pressure, but not diastolic blood pressure, when compared with a paraffin control. Heart rate and anxiety were reduced by a small amount the day following the completion of lemon aromatherapy (103455).
• Nausea and vomiting. It is unclear if aromatherapy with lemon oil is beneficial in palliative care patients with nausea and vomiting. Details: A small observational study in hospitalized palliative care patients with advanced cancer has found that administering aromatherapy with lemon oil pads relieves nausea and vomiting in 73% of applications (110778). The interpretation of these findings is limited by the use of a retrospective chart review and the lack of a comparator group.
• Obesity. Although there is interest in using lemon orally for obesity, there is insufficient reliable information about the clinical effects of lemon for this condition.
• Oral mucositis. Lemon has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A randomized, controlled trial in patients with head and neck cancer receiving external beam radiotherapy 5 days weekly shows that using a 2:1 oral honey-lemon throat spray four to eight times daily, beginning 1 day prior to radiotherapy initiation and continuing for 5 weeks, does not improve severity of mucositis when compared with oral benzydamine hydrochloride throat spray applied four to eight times daily. The actual rate of oral mucositis occurrence is 65% in those receiving the honey-lemon spray, compared with 35% with the benzydamine hydrochloride spray; however, this difference was not statistically significant (107487). This study may have been inadequately powered to detect a difference between groups. Also, the validity of these findings is limited due to the lack of objective outcome measures.
• Postoperative nausea and vomiting (PONV). It is unclear if aromatherapy with lemon essential oil is beneficial in patients with PONV. Details: Preliminary research in patients undergoing lower extremity fracture surgery shows that aromatherapy with lemon essential oil started the morning of surgery, then every 2 hours to the end of surgery, in the recovery room, and 16 hours after surgery reduces the frequency, severity, and amount of PONV, and the frequency of anti-emetic drug administration after surgery, when compared with control. The intensity of pain is also reduced, but not the amount of post-operative opioid needed (112956).
• Pregnancy-induced nausea and vomiting. It is unclear if aromatherapy with lemon essential oil is beneficial in patients with nausea and vomiting due to pregnancy. Details: A small clinical study in pregnant patients shows that practicing aromatherapy with 2 drops of lemon essential oil placed on a cotton ball as needed modestly reduces pregnancy-induced nausea and vomiting on 2 of 4 days of the study when compared with placebo (93475).
• Radiation-induced sialadenitis. Aromatherapy with lemon essential oil has only been evaluated in combination with other essential oils; its effect when used alone is unclear. Details: A small clinical study in patients with thyroid cancer shows that receiving 10-minute aromatherapy baths with lemon and ginger essential oils prior to meals for 2 weeks before treatment with radioactive iodine therapy attenuates damage to the salivary gland when compared with distilled water baths (98129).
• Respiratory tract infections. Although there is interest in using lemon orally for respiratory tract infections such as cold and flu, there is insufficient reliable information about the clinical effects of lemon for these conditions. More evidence is needed to rate lemon for these uses.

(Read more about LEMON)

EFFECTIVE

• Bowel preparation. Oral sodium phosphate is effective for cleansing the colon in preparation for colonoscopy; however, it is unclear whether sodium phosphate is as effective as polyethylene glycol (PEG) solution. Some products are approved by the US Food and Drug Administration (FDA) for this use. However, due to the potential for kidney damage, sodium phosphate is not recommended as first-line therapy. Details: Sodium phosphate tablets (OsmoPrep, Salix Pharmaceuticals; Visicol, Salix Pharmaceuticals) are FDA-approved for cleansing the colon in preparation for colonoscopy. Clinical research shows that using the OsmoPrep formulation can achieve an "excellent" or "good" response rate, which is defined as having 90% of the mucosa visible with only some or little suctioning needed, in 94% to 97% of patients (88133). Similarly, using the specific product Visicol has been shown to achieve an excellent or good response rate in 82% to 86% of patients (94674). Non-FDA-approved sodium phosphate products have also been investigated. One such product (Fleet Phospho-soda, C. B. Fleet Co.) has been shown to achieve adequate bowel cleansing in 23% to 89% of patients (93846,94673). Another sodium phosphate tablet preparation (Clicolon tablets, Korea Pharma Co.) has been shown to achieve adequate bowel cleansing in 63% to 93% of patients (93848,93850,93853). Excellent or good bowel cleansing was found in 98.6% of patients using a 32-tablet regimen of other sodium phosphate tablets (Quiklean, Universal Integrated Corporation) (107008). Reasons for the differences in the percentage of patients who achieve adequate bowel cleansing with the same sodium phosphate product may relate to the method used to analyze bowel cleansing, differences in diet followed during bowel cleansing, and demographic factors (93846,93848,93850,93853). Various preparations (OsmoPrep, Salix Pharmaceuticals; Visicol, Salix Pharmaceuticals; Clicolon tablets, Korea Pharma Co.; Quiklean, Universal Integrated Corporation) have been used which contain 1.102 grams of sodium phosphate monobasic monohydrate and 0.398 grams of sodium phosphate dibasic anhydrous. These products have been taken as 3-4 tablets with 8 ounces of water every 15 minutes for a total of 20 tablets the evening before colonoscopy, and 3-4 tablets with 8 ounces of water every 15 minutes for a total of 12-20 tablets the morning of a colonoscopy (88133,93848,93850,94674,107008). Also, sodium phosphate solution (Fleet Phospho-soda, C. B. Fleet Co.) containing sodium hydrogen phosphate 24.4 grams and disodium phosphate dodecahydrate 10.8 grams has also been used the morning and evening before the procedure (93846). Numerous publications have compared the bowel cleansing activity of sodium phosphate with PEG solution. When given as a split-overnight dosage, sodium phosphate is about as effective as PEG solutions in achieving adequate bowel cleansing. However, when day-before dosage is used, PEG is more effective for bowel cleansing than sodium phosphate (93861,93862,107008). Sodium phosphate and PEG may have different effectiveness depending on the colonic site assessed. When only trials assessing descending colon cleansing are considered, sodium phosphate is found to work similarly to PEG solutions. When only studies assessing ascending colon cleansing are considered, PEG is more effective for bowel cleansing than sodium phosphate (93861). Also, a large clinical trial in outpatients scheduled for non-sedated colonoscopy shows that receiving PEG resulted in an easier insertion and a less painful colonoscopy when compared with receiving sodium phosphate (104473). However, in patients with chronic constipation, sodium phosphate seems to be preferable. A meta-analysis of three small clinical studies in adults with chronic constipation shows that using sodium phosphate has an 87% greater chance of a successful bowel preparation when compared with using PEG (104472). Sodium phosphate is not recommended as first-line therapy for bowel preparation prior to colonoscopy due to the potential for kidney damage (93863,94672). In fact, one sodium phosphate preparation (Fleet Phospho-soda, C. B. Fleet Co.) that was previously approved as an over-the-counter supplement for bowel preparation in the US was withdrawn from the market for this indication in December 2008 due to concerns for phosphate-induced kidney disease (94672). Of the sodium phosphate products that are still approved by the FDA, current guidelines recommend that these products not be used for bowel cleansing in patients with kidney disease, pre-existing electrolyte disturbances, congestive heart failure, cirrhosis, ascites, or inflammatory bowel disease. Guidelines also recommend that caution should be used if these products are prescribed for patients who are elderly, hypertensive, or taking certain classes of drugs (94672). For small bowel preparation for endoscopy, a meta-analysis suggests that sodium phosphate is no more effective than fasting alone (93860).
• Hypophosphatemia. Oral or intravenous phosphate salts are effective for the prevention or treatment of hypophosphatemia. Some products are approved by the US Food and Drug Administration (FDA) for this use. Details: Taking sodium or potassium phosphate orally is effective for preventing and treating hypophosphatemia (15). Treating hypophosphatemia with oral phosphates requires monitoring of serum electrolyte levels to determine appropriate dosing (15). The FDA-approved intravenous (IV) product is also used for the correction of hypophosphatemia (8302,8303,88135). FDA-approved intravenous (IV) sodium phosphate or potassium phosphate 15-30 mmol is typically given over 2-12 hours. Higher doses have been used if needed to increase efficacy (8302,8303,88135).

LIKELY EFFECTIVE

• Constipation. Oral or rectal sodium phosphate is approved by the US Food and Drug Administration (FDA) as an ingredient in over-the-counter (OTC) products to treat constipation. Details: Sodium phosphate is an FDA-permitted ingredient of oral and rectal OTC products intended for the treatment of constipation (88107).
• Dyspepsia. Oral aluminum phosphate and calcium phosphate are approved by the US Food and Drug Administration (FDA) as ingredients in over-the-counter (OTC) antacids. Details: Aluminum phosphate and calcium phosphate are FDA-permitted ingredients of oral OTC products intended for use as antacids (88107).
• Hypercalcemia. Although other treatments are preferred, oral non-calcium phosphate salts are beneficial for treatment of mild to moderate hypercalcemia. Details: Taking phosphate salts (except calcium phosphate) orally is effective for treating mild to moderate hypercalcemia (88144,88145). Treating hypercalcemia with oral phosphates requires monitoring of serum electrolyte levels to determine appropriate dosing (15); other agents are now preferred (6479). Intravenous phosphates should be avoided due to the risk of calcium precipitation in vital organs (metastatic calcification) (15,88144,88145).

POSSIBLY EFFECTIVE

• Kidney stones (nephrolithiasis). Oral potassium phosphate seems to be beneficial for prevention of kidney stones in individuals with hypercalciuria. Details: Taking potassium phosphate orally may help prevent calcium oxalate kidney stones in patients with hypercalciuria (6470). Clinical research in adults with absorptive hypercalciuria and at high risk for stone formation shows that taking a specific slow-release potassium phosphate product (Uro-Phos-K, Mission Pharmacal), providing phosphate 620 mg orally twice daily for 4 days, reduces urinary calcium excretion by 35% to 40% (2208,2209). Potassium and sodium phosphate salts providing 1200-1500 mg of elemental phosphate daily have been used (2209,6470).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Athletic performance. The evidence is mixed as to whether oral sodium phosphate improves cycling or running performance. Most research suggests that oral calcium phosphate and potassium phosphate are not beneficial. Details: Clinical research shows that taking calcium phosphate or potassium phosphate orally does not improve running or cycling performance (2499,9300,8301). Evidence for the use of sodium phosphate to improve cycling performance is mixed. One very small clinical study shows that taking sodium phosphate as tribasic sodium phosphate dodecahydrate for 6 days before a 10-mile cycling trial increases mean power output by about 10% and decreases the time needed to complete the trial by 3% in trained male cyclists (88150). Other small clinical trials in trained cyclists show that taking the same form of sodium phosphate as 50 mg/kg of fat-free mass in four divided doses daily for 6 days modestly improves work, power output, and peak oxygen uptake and reduces heart rate during high-intensity cycling exercise when compared to baseline (93857,93858,93859,107007). However, conflicting research shows that taking a similar dosage of this form of sodium phosphate does not improve time trial performance, work accomplished relative to energy expenditure, power output, or oxygen uptake in trained cyclists (93855,93856,107007). Sodium phosphate has also been evaluated for improving running performance, with mixed findings. Two small clinical trials in female athletes show that tribasic sodium phosphate dodecahydrate 50 mg/kg of fat-free mass taken in four divided doses daily for 6 days moderately improves repeated sprint times when compared with placebo (93843,93844). However, taking the same dosage does not significantly improve sprint times in male athletes (93849). Also, sodium phosphate does not seem to improve endurance or aerobic capacity in treadmill tests (8301,93854). Reasons for the discrepancies regarding the effects of sodium phosphate on athletic performance are not entirely clear, but likely relate to the very small number of participants in the included trials.
• Diabetic ketoacidosis. Potassium phosphate infusion is not recommended as first-line therapy for adults with diabetic ketoacidosis. Details: Clinical research shows that intravenous infusion of potassium phosphate 8.5 mmol/hour (approximately 6 grams of phosphate over 24 hours) along with potassium chloride 12.5 mEq/hour provides no benefit over potassium chloride alone in adults with diabetic ketoacidosis (88149). Guidelines for the treatment of diabetic ketoacidosis in the both the US and UK do not recommend phosphate replacement for most patients. However, it may be considered in specific cases, such as cardiac dysfunction, anemia, respiratory depression, and serum phosphate concentrations below 1 mg/dL (107349,107350A).
• Osteoporosis. Calcium phosphate seems to be beneficial for bone density improvement; however, it does not seem to be more beneficial than calcium carbonate. Details: In postmenopausal adults with osteoporosis and low phosphate intakes, taking calcium 1800 mg daily as tricalcium phosphate for 12 months improves lumbar spine and hip densities. However, it is no more effective than taking the same amount of calcium as calcium carbonate (93847). The calcium products were used in combination subcutaneous teriparatide and oral vitamin D (cholecalciferol) 1000 IU daily.
• Refeeding syndrome. It is unclear if intravenous potassium phosphate or sodium phosphate is beneficial for prevention of refeeding syndrome. Details: Preliminary clinical research shows that giving intravenous sodium and potassium phosphates, 50 mmol (1.56 grams) phosphate over 24 hours, prevents the refeeding syndrome seen when restarting adequate nutrition after severe malnutrition or starvation when compared with historical controls (88148). More evidence is needed to rate phosphate salts for these uses.

(Read more about PHOSPHATE SALTS)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Cancer. Observational research has found that daily intake of oranges and/or tangerines is associated with a reduced odds of developing nasopharyngeal carcinoma when compared with consuming oranges and/or tangerines less than once a week (28608). More evidence is needed to rate tangerine for this use.

(Read more about TANGERINE)

LIKELY SAFE ...when used orally or intravenously and appropriately. Calcium is safe when used in appropriate doses (7555,12928,12946,95817). However, excessive doses should be avoided. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: Age 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg; 19-50 years, 2500 mg; 51+ years, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stone, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Other clinical studies suggest that, when combined with vitamin D supplementation, calcium supplementation is not associated with an increased risk of CVD, CHD, or MI (93533,107231). Other analyses report conflicting results and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients not to consume more than the recommended daily intake of 1000-1200 mg per day, to consider total calcium intake from both dietary and supplemental sources (17484), and to combine calcium supplementation with vitamin D supplementation (93533).

POSSIBLY UNSAFE ...when used orally in excessive doses. The National Academy of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 19-50 years, 2500 mg; 51 years and older, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Other clinical studies suggest that, when combined with vitamin D supplementation, calcium supplementation is not associated with an increased risk of CVD, CHD, or MI (93533,107231). Other analyses report conflicting results and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients to not consume more than the recommended daily intake of 1000-1200 mg per day, to consider total calcium intake from both dietary and supplemental sources (17484), and to combine calcium supplementation with vitamin D supplementation (93533).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Calcium is safe when used in appropriate doses (17506).

CHILDREN: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (945,1586,3263,3264,17506). The World Health Organization (WHO) recommends prescribing oral calcium supplementation 1.5-2 grams daily during pregnancy to those with low dietary calcium intake to prevent pre-eclampsia (97347).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the same daily tolerable upper intake level (UL) for calcium according to age independent of pregnancy status: 9-18 years, 3000 mg; 19-50 years, 2500 mg (17506). Doses over these amounts might increase the risk of neonatal hypocalcemia-induced seizures possibly caused by transient neonatal hypoparathyroidism in the setting of excessive calcium supplementation during pregnancy, especially during the third trimester. Neonatal hypocalcemia is a risk factor for neonatal seizures (97345).

(Read more about CALCIUM)

LIKELY SAFE ...when used orally and appropriately, short-term. Various liquid extracts of Echinacea purpurea have been used safely for up to 10 days, including EchinaGuard (Madaus AG) 20 drops every 2 hours for 1 day, then three times daily (10320), or Echinilin (Inovobiologic Inc.) 40 mL in divided doses for 1 day, then 15 mL in divided doses daily thereafter (12355,20062). Other liquid extracts have been used safely for relatively longer periods, including Echinaforce (A. Vogel Bioforce AG) 2.4 grams daily for 4 months or 1.6 grams daily for 6 months (7087,18225), and Echinacin (Madaus AG) 5 mL twice daily for 10 days, or 4 mL twice daily for 8 weeks (3282,10802). Specific solid dosage forms of echinacea that have been used safely for up to 10 days include Echinacea purpurea above-ground parts (EchinaFresh, Enzymatic Therapy) 300 mg daily (11970), and mixtures of Echinacea purpurea and Echinacea angustifolia herb in divided doses of 6 grams to 10.5 grams for 1 day then 3 grams to 5.1 grams daily (10800,17519,20059). A specific Echinacea angustifolia extract (ExtractumPharma ZRT) has also been used with apparent safety at a dose of 40 mg once or twice daily for up to 7 days (20064,103233). An Echinacea purpurea product (Natures Resource) has been used safely at a dose of 1.8 grams daily for 8 weeks (17521), and echinacea (Puritan's Pride) has been used safely at 8 grams daily for 28 days (20066).

POSSIBLY SAFE ...when used topically, short-term. A specific cream (Linola Plus Cream, Dr. August Wolff GmbH & Co.) containing echinacea extract (WO 3260) has been applied to the skin safely 2-3 times daily for up to 12 weeks (97499). There is insufficient reliable evidence about the safety of echinacea when used parenterally.

CHILDREN: POSSIBLY SAFE
when used orally, short-term. Some clinical research shows that an extract of the above-ground parts of Echinacea purpurea (EC31J2, Echinacin Saft, Madaus AG) in a dose of 3.75 mL twice daily (for ages 2 years to 5 years) or 7.5 mL twice daily (for ages 6 years to 11 years) is safe when used for up to 10 days (4989). However, about 7% of children experienced a rash after taking echinacea, which might have been caused by an allergic reaction (4989). There is concern that allergic reactions could be severe in some children. The Medicines and Healthcare Products Regulatory Agency in the United Kingdom recommends against the use of oral echinacea products in children under 12 years of age due to this risk of allergic reaction (18207). In contrast, another clinical study in children 4-12 years old shows that a specific Echinacea purpurea product (Echinaforce Junior, A. Vogel) does not cause allergic or urticarial reactions more frequently than vitamin C (105719).

PREGNANCY: POSSIBLY SAFE
when used orally, short-term. There is preliminary evidence that mothers can safely use echinacea in the form of E. purpurea or E. angustifolia solid dosage forms, 250-1000 mg daily, or tinctures, up to 30 drops daily, for 5 days to 7 days during the first trimester without adversely affecting the fetus (7056,13418,15123). There is insufficient reliable information available about the safety of echinacea when used for longer than 7 days.

LACTATION:
Insufficient reliable information available; avoid using.

(Read more about ECHINACEA)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Grapefruit has Generally Recognized as Safe status (GRAS) in the US (4912).

POSSIBLY SAFE ...when used orally and appropriately for medicinal purposes. A grapefruit seed extract has been safely used in clinical research (5866). In addition, capsules containing grapefruit pectin 15 grams daily have been used in clinical research for up to 16 weeks (2216).

POSSIBLY UNSAFE ...when used orally in excessive amounts. Preliminary population research shows that consuming a quarter or more of a whole grapefruit daily is associated with a 25% to 30% increased risk of postmenopausal breast cancer (14858). Grapefruit juice is thought to reduce estrogen metabolism resulting in increased endogenous estrogen levels. More evidence is needed to validate this finding.

PREGNANCY AND LACTATION:
There is insufficient reliable information available about the safety of using medicinal amounts of grapefruit during pregnancy and lactation; avoid using.

(Read more about GRAPEFRUIT)

LIKELY SAFE ...when used in amounts commonly found in foods. Lemon has Generally Recognized as Safe (GRAS) status in the US (4912).

POSSIBLY SAFE ...when inhaled in amounts used for aromatherapy, short-term. Lemon essential oil has been used with apparent safety as aromatherapy for up to 2 weeks in clinical research (93475,98128,98129). There is insufficient reliable information available about the safety of lemon when used topically, or when used orally or intranasally in medicinal amounts.

PREGNANCY AND LACTATION:
Insufficient reliable information available. Avoid using in amounts greater than those typically found in foods.

(Read more about LEMON)

LIKELY SAFE ...when used orally and appropriately short-term (15). ...when sodium phosphate is used rectally and appropriately, no more than once every 24 hours, short-term (104471). Long-term use or high doses used orally or rectally require monitoring of serum electrolytes (2494,2495,2496,2497,2498,3092,112922). ...when used intravenously. Potassium phosphate is an FDA-approved prescription drug (15).

POSSIBLY UNSAFE ...when phosphate (expressed as phosphorus) intake exceeds the tolerable upper intake level (UL) of 4 grams daily for adults under 70 years and 3 grams daily for adults older than 70. Hyperphosphatemia, resulting in electrolyte disturbances, alterations in calcium homeostasis, and calcification of nonskeletal tissues, may occur (7555). ...when used rectally more frequently than once every 24 hours, in excessive doses, with longer retention enema time, or in older patients with comorbidity or renal impairment (112922). The US Food and Drug Administration (FDA) warns that this may increase the risk of hyperphosphatemia, dehydration, and electrolyte imbalances leading to kidney and heart damage (104471).

CHILDREN: LIKELY SAFE
when used orally and appropriately at recommended dietary allowances (RDAs). The daily RDAs are: children 1-3 years, 460 mg; children 4-8 years, 500 mg; males and females 9-18 years, 1250 mg (7555). ...when sodium phosphate is used rectally and appropriately, no more than once every 24 hours, short-term in children 2 years and older (104471). ...when used intravenously. Intravenous potassium phosphate is an FDA-approved prescription drug (15).

CHILDREN: POSSIBLY UNSAFE
when phosphate (expressed as phosphorus) intake exceeds the tolerable upper intake level (UL) of 3 grams daily for children 1-8 years of age and 4 grams daily for children 9 years and older. Hyperphosphatemia, resulting in electrolyte disturbances, alterations in calcium homeostasis, and calcification of nonskeletal tissues, may occur (7555). ...when sodium phosphate is used rectally more frequently than once every 24 hours, or in children under 2 years of age or with Hirchsprung disease (112922). The US Food and Drug Administration (FDA) warns that these uses may increase the risk of hyperphosphatemia, dehydration, and electrolyte imbalances leading to kidney and heart damage (104471).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately at the recommended dietary allowance (RDA) of 1250 mg daily for individuals 14-18 years of age and 700 mg daily for those over 18 years of age (7555). ...when sodium phosphate is used rectally and appropriately short-term (15). ...when used intravenously. Intravenous potassium phosphate is an FDA-approved prescription drug (15).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when phosphate (expressed as phosphorus) intake exceeds the tolerable upper intake level (UL). Hyperphosphatemia, resulting in electrolyte disturbances, alterations in calcium homeostasis, and calcification of nonskeletal tissues, may occur. The UL during pregnancy is 3.5 grams daily. During lactation, the UL is 4 grams daily (7555).

(Read more about PHOSPHATE SALTS)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Tangerine has Generally Recognized as Safe (GRAS) status in the US (4912). There is insufficient reliable information available about the safety of tangerine when used orally or topically as a medicine.

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about TANGERINE)

ALUMINUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.  Details Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease (21631). However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption (93006).

BISPHOSPHONATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium reduces the absorption of bisphosphonates.  Details Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates (12937).

CALCIPOTRIENE (Dovonex) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Taking calcipotriene with calcium might increase the risk for hypercalcemia.  Details Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia (12938). Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.

CALCIUM CHANNEL BLOCKERS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.  Details Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects (6124). But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers (12939,12947).

CEFTRIAXONE (Rocephin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.  Details Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction (15794,21632). So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.  Details Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin (12940). However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin (38960).

DILTIAZEM (Cardizem, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of diltiazem.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

DOLUTEGRAVIR (Tivicay) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of dolutegravir.  Details Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation (93578).

ELVITEGRAVIR (Vitekta) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of elvitegravir.  Details Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation (94166).

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption and effectiveness of levothyroxine.  Details Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes (5082). Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism (5081,5082,6137).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.  Details Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients (38953). Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

QUINOLONE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption of quinolone antibiotics.  Details Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut (4412,10339,21638,38570).

RALTEGRAVIR (Isentress) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Calcium may reduce levels of raltegravir.  Details Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir (94164). However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure (94165).

SOTALOL (Betapace) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium seems to reduce the absorption of sotalol.  Details Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes (10018).

TETRACYCLINE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium seems to reduce the absorption of tetracycline antibiotics.  Details Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut (1843).

THIAZIDE DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.  Details Thiazides reduce calcium excretion by the kidneys (1902). Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

VERAPAMIL (Calan, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of verapamil.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

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CAFFEINE Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Echinacea can increase plasma levels of caffeine by inhibiting its metabolism.  Details Echinacea seems to increase plasma concentrations of caffeine by around 30% (12155). This is likely due to inhibition of cytochrome P450 1A2 (CYP1A2) by echinacea.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Echinacea might inhibit the metabolism of CYP1A2 and increase plasma levels of some drugs.  Details Echinacea appears to inhibit CYP1A2 enzymes in humans. Additionally, echinacea seems to increase plasma concentrations of caffeine, a CYP1A2 substrate, by around 30% (12155). Theoretically, echinacea might increase levels of other drugs metabolized by CYP1A2.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Echinacea may induce hepatic CYP3A4 and inhibit intestinal CYP3A4. This may increase or decrease levels of drugs metabolized by CYP3A4.  Details Several clinical trials have shown that taking echinacea for up to one month does not significantly affect the metabolism of various CYP3A4 substrates, including midazolam, docetaxel, etravirine, lopinavir-ritonavir, and darunavir-ritonavir (13712,48618,88164,88165). However, other clinical research shows that echinacea may increase the clearance of midazolam, suggesting that echinacea might induce CYP3A4 (48618). The discrepancy is thought to be due to differing effects of echinacea on intestinal versus hepatic CYP3A4 enzymes. Echinacea appears to induce hepatic CYP3A4 but inhibit intestinal CYP3A4 (12155). In some cases, these effects might cancel each other out, but in others, drug levels may be increased or decreased depending on the level of effect at hepatic and intestinal sites. The effect of echinacea on CYP3A4 activity may differ depending on the CYP3A4 substrate (6450,11026,88162,88167).

DARUNAVIR (Prezista) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, echinacea may interfere with the metabolism of darunavir; however, a small clinical study found no effect.  Details Darunavir is metabolized by cytochrome P450 3A4 (CYP3A4) and is administered with the CYP3A4 inhibitor ritonavir to increase its plasma concentrations. Echinacea has variable effects on CYP3A4, but administration of an E. purpurea root extract (Arkocapsulas Echinacea, Arkopharma) 500 mg four times daily for 14 days did not affect darunavir/ritonavir pharmacokinetics in 15 HIV-infected patients (88163,93578).

DOCETAXEL (Taxotere) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, echinacea may interfere with the metabolism of docetaxel; however, a small clinical study found no effect.  Details Docetaxel is metabolized by cytochrome P450 3A4 (CYP3A4). Echinacea has variable effects on CYP3A4, but taking E. purpurea whole plant extract (Echinaforce, A. Vogel Biopharma AG) 20 drops three times daily for 2 weeks did not alter the pharmacokinetics of docetaxel in one clinical study (88164).

ETOPOSIDE (VePesid) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Echinacea may increase levels of etoposide.  Details In one report, concomitant use of etoposide and echinacea was associated with more severe thrombocytopenia than the use of etoposide alone, suggesting inhibition of etoposide metabolism (20082). Etoposide is a cytochrome P450 3A4 (CYP3A4) substrate. Echinacea has variable effects on CYP3A4, but some studies have reported inhibition of the enzyme (6450,11026,12155,88162,88167).

ETRAVIRINE (Intelence) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, echinacea may interfere with the metabolism of etravirine; however, a small clinical study found no effect.  Details Etravirine is metabolized by cytochrome P450 3A4 (CYP3A4). Echinacea has variable effects on CYP3A4, but taking E. purpurea root extract (Arkocapsulas Echinacea, Arkopharma) 500 mg three times daily for 14 days did not alter the pharmacokinetics of etravirine in HIV-infected patients (88165,93578).

IMMUNOSUPPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Echinacea has immunostimulant activity which may interfere with immunosuppressant therapy.  Details Theoretically, echinacea may interfere with immunosuppressant therapy because of its immunostimulant activity (3279,6388,6389,12639).

LOPINAVIR/RITONAVIR (Kaletra) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, echinacea may interfere with the metabolism of lopinavir; however, a small clinical study found no effect.  Details Lopinavir is metabolized by cytochrome P450 3A4 (CYP3A4) and is administered with the CYP3A4 inhibitor ritonavir to increase its plasma concentrations. Echinacea has variable effects on CYP3A4, but taking E. purpurea (Echinamide, Natural Factors Nutritional Products, Inc.) 500 mg three times daily for 14 days did not alter the pharmacokinetics of lopinavir/ritonavir in healthy volunteers (48618,93578).

MIDAZOLAM (Versed) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = B Theoretically, echinacea may increase the metabolism of intravenous midazolam.  Details Echinacea induces hepatic CYP3A4 and might decrease plasma levels of midazolam by about 20%, reducing the effectiveness of intravenous midazolam (12155). Echinacea also appears to inhibit intestinal CYP3A4, which could theoretically increase the bioavailability of oral midazolam. This may cancel out the decrease in availability caused by induction of hepatic CYP3A4, such that overall plasma levels after oral administration of midazolam are not affected by echinacea.

WARFARIN (Coumadin) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = B Echinacea seems to increase the clearance of warfarin, although the effect may not be clinically significant.  Details Preliminary clinical research in healthy male volunteers suggests that taking echinacea increases the clearance of the active S-isomer of warfarin after a single dose of warfarin, but there was not a clinically significant effect on the INR (20083).

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ACEBUTOLOL (Sectral) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can decrease blood levels of acebutolol, potentially decreasing the clinical effects of acebutolol.  Details Clinical research shows that grapefruit juice can modestly decrease acebutolol levels by 7% and reduce peak plasma concentration by 19% by inhibiting organic anion transporting polypeptide (OATP) (17603,18101). The acebutolol half-life is also extended by 1.1 hours when grapefruit juice is consumed concomitantly (18101). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

ALISKIREN (Tekturna, Rasilez) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can decrease blood levels of aliskiren, potentially decreasing the clinical effects of aliskiren.  Details Clinical research shows that grapefruit juice can decrease aliskiren levels by approximately 60% by inhibiting organic anion transporting polypeptide (OATP) (91428). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

AMIODARONE (Cordarone) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of amiodarone, potentially increasing the effects and adverse effects of amiodarone.  Details Clinical research shows that grapefruit juice inhibits metabolism and increases absorption of amiodarone. Grapefruit juice increases amiodarone plasma levels by 50% and peak concentration by 84% (17601,17672,22120).

AMPRENAVIR (Agenerase) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice might decrease blood levels of amprenavir, although this is not likely to be clinically significant.  Details Some clinical research shows that grapefruit juice can slightly decrease amprenavir levels (17673); however, this is probably not clinically significant.

ARTEMETHER (Artenam, Paluther) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of oral artemether, potentially increasing the effects and adverse effects of artemether.  Details Clinical research shows that grapefruit juice increases the levels of oral artemether by 90% to 250% in healthy males (5065,5066).

BENZODIAZEPINES Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice might increase blood levels of some oral benzodiazepines, potentially increasing the effects and adverse effects of these drugs.  Details Clinical research shows that grapefruit juice can increase plasma triazolam concentrations. Repeated consumption of grapefruit juice greatly increases triazolam concentrations and prolongs the half-life, probably due to inhibition of cytochrome P450 3A4 (CYP3A4) (7776,22118,22131,22133). Some studies show that grapefruit juice, particularly when taken in large quantities, reduces the clearance and increases the maximum blood levels, area under the plasma concentration curve (AUC), and duration of effect of midazolam. However, there is no effect on intravenous midazolam (4300,10159,11275,17601,22117,22119,16711,91427,95978). Grapefruit juice has also been shown to increase the maximum blood levels and duration of effect of diazepam, but the clinical significance of this is not known (3228). This interaction does not appear to occur with alprazolam (17674).

BLONANSERIN (Lonasen) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of blonanserin, potentially increasing the effects and adverse effects of blonanserin.  Details Blonanserin is metabolized primarily by cytochrome P450 3A4 (CYP3A4). A small clinical study shows that taking grapefruit juice along with oral blonanserin increases exposure to blonanserin almost 6-fold due to inhibition of intestinal CYP3A4 by grapefruit juice and prolongs the elimination half-life of blonanserin by 2.2-fold due to inhibition of hepatic CYP3A4 by grapefruit juice (96943).

BUDESONIDE (Entocort, UCERIS) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of budesonide, potentially increasing the effects and adverse effects of budesonide.  Details Budesonide is metabolized by cytochrome P450 3A4 (CYP3A4). A small clinical study shows that taking grapefruit juice along with oral budesonide increases the plasma concentration of budesonide. This effect is attributed to grapefruit-induced inhibition of CYP3A4 in both the colon and small intestine (91425).

BUSPIRONE (BuSpar) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of buspirone, potentially increasing the effects and adverse effects of buspirone.  Details Clinical research shows that grapefruit juice increases absorption and plasma concentrations of buspirone (3771).

CAFFEINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Grapefruit juice can decrease the clearance of caffeine, potentially increasing the effects and adverse effects of caffeine.  Details Clinical research shows that grapefruit juice decreases caffeine clearance (4300).

CALCIUM CHANNEL BLOCKERS Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of oral calcium channel blockers, potentially increasing the effects and adverse effects of these drugs.  Details Clinical research shows that grapefruit juice increases absorption and plasma concentrations of amlodipine (523), nifedipine (528,22114), nisoldipine (529), verapamil (7779,8285), felodipine, nimodipine, nicardipine, diltiazem, pranidipine, nitrendipine, and manidipine (524,528,1388,4300,7780,11276,22136,53338,22138,22139) (22140,22141,22142,22143,22147,22148,22149,53367,22158), This interaction is likely the result of the inhibition of intestinal metabolism of these drugs by CYP3A4 (7779,7780), although some research suggests grapefruit may alter plasma drug levels by reducing the rate of gastric emptying (22167). Consuming grapefruit juice 1 liter daily increases steady state concentrations of verapamil by as much as 50% (8285). However, some references dispute the clinical relevance of the interactions with amlodipine, diltiazem, and verapamil (3230,4300,22159). Other research in healthy individuals suggests plasma levels of felodipine and nifedipine are not affected when given intravenously (22144,22146). There is considerable interindividual variability in the effect of grapefruit juice on drug metabolism, which might account for inconsistent study results (7777,7779,8285). In healthy older adults, the hemodynamic response to felodipine plus grapefruit juice might be influenced by altered autonomic regulation. In older healthy adults, a single dose of grapefruit juice and felodipine enhanced the blood pressure-lowering effects of felodipine. However, after a week of grapefruit juice and felodipine (steady state), the hypotensive activity was reduced, possibly due to compensatory tachycardia (1392). Research indicates it is necessary to withhold grapefruit juice for as long as 3 days to avoid interactions with felodipine and nisoldipine (5068,5069,6453,22145).

CARBAMAZEPINE (Tegretol) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of carbamazepine, potentially increasing the effects and adverse effects of carbamazepine.  Details Clinical research shows that grapefruit juice increases absorption and plasma concentrations of carbamazepine (524).

CARVEDILOL (Coreg) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of carvedilol, potentially increasing the effects and adverse effects of carvedilol.  Details Clinical research shows that grapefruit juice increases the bioavailability of a single dose of carvedilol by 16% (5071).

CELIPROLOL (Celicard) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of celiprolol, potentially decreasing the clinical effects of celiprolol.  Details In human research, taking grapefruit juice within two hours of celiprolol appears to decrease absorption and blood levels of celiprolol by approximately 85% (91421). This interaction is due to grapefruit-induced inhibition of organic anion transporting polypeptide (OATP) (17603,17604,22161). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

CISAPRIDE (Propulsid) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of cisapride, potentially increasing the effects and adverse effects of cisapride.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cisapride. According to the cisapride prescribing information, grapefruit juice is contraindicated in patients taking cisapride (1383,3226,17601,22164,22165).

CLOMIPRAMINE (Anafranil) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, grapefruit juice might increase blood levels of clomipramine, potentially increasing the effects and adverse effects of clomipramine.  Details Case reports have shown that clomipramine trough levels increase significantly after the addition of grapefruit juice to the therapeutic regimen (5064).

CLOPIDOGREL (Plavix) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of the active metabolite of clopidogrel, thereby decreasing the antiplatelet effect of clopidogrel.  Details Clopidogrel is an antiplatelet prodrug that is metabolized primarily by cytochrome P450 2C19 (CYP2C19) to form the active metabolite. A small clinical study shows that taking grapefruit juice with clopidogrel decreases plasma levels of the active metabolite by more than 80% and impairs the antiplatelet effect of clopidogrel. This effect is possibly due to grapefruit-induced inhibition of CYP2C19 (91419).

COLCHICINE Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, grapefruit juice might increase blood levels of colchicine, potentially increasing the effects and adverse effects of colchicine.  Details Colchicine is an alkaloid that undergoes P-glycoprotein (P-gp) mediated drug efflux in the intestines, followed by metabolism by cytochrome P450 3A4 (CYP3A4). There is concern that grapefruit juice will increase the effects and adverse effects of colchicine due to grapefruit-induced inhibition of P-gp and/or CYP3A4. In vitro evidence shows that grapefruit juice increases absorption of colchicine by inhibiting P-gp (94158). A case of acute colchicine toxicity has been reported for an 8-year-old female who drank grapefruit juice while taking high-dose colchicine, long-term (94157). However, one small clinical study in healthy adults shows that drinking grapefruit juice 240 mL twice daily for 4 days does not affect the bioavailability or adverse effects of a single dose of colchicine 0.6 mg taken on the fourth day (35762).

CYCLOSPORINE (Neoral, Sandimmune) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of oral cyclosporine, potentially increasing the effects and adverse effects of cyclosporine.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cyclosporine (522,11270,22113,22150,22152,22153,22154,22155). The mechanism of action is unclear. However, there is no effect on intravenous cyclosporine (22151).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP1A2.  Details In vitro research suggests that grapefruit juice might inhibit CYP1A2 enzymes (12479). So far, this interaction has not been reported in humans.

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP2C19.  Details In vitro research suggests that grapefruit juice might inhibit CYP2C19 enzymes (12479). Also, a small clinical study shows that taking grapefruit juice with clopidogrel, an antiplatelet prodrug that is metabolized primarily by CYP2C19, decreases plasma levels of the active metabolite and impairs the antiplatelet effect of clopidogrel. This effect is likely due to grapefruit-induced inhibition of CYP2C19 (91419).

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP2C9.  Details In vitro research suggests that grapefruit juice might inhibit CYP2C9 enzymes (12479). So far, this interaction has not been reported in humans.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase levels of drugs metabolized by CYP3A4.  Details Clinical research shows that grapefruit juice can inhibit CYP3A4 metabolism of drugs, causing increased drug levels and potentially increasing the risk of adverse effects (3227,3774,8283,8285,8286,22129,91427,104190). When taken orally, effects of grapefruit juice on CYP3A4 levels appear to last at least 48 hours (91427). Grapefruit's ability to inhibit CYP3A4 has even been harnessed to intentionally increase levels of venetoclax, which is metabolized by CYP3A4, in an elderly patient with acute myeloid leukemia who could not afford full dose venetoclax. The lower dose of venetoclax in combination with grapefruit juice resulted in serum levels of venetoclax in the therapeutic reference range of full dose venetoclax and positive treatment outcomes for the patient (112287). Professional consensus recommends the consideration of patient age, existing medical conditions, additional medications, and the potential for additive adverse effects when evaluating the risks of concomitant use of grapefruit juice with any medication metabolized by CYP3A4. While all patients are at risk for interactions with grapefruit juice consumption, patients older than 70 years of age and those taking multiple medications are at the greatest risk for a serious or fatal interaction with grapefruit juice (95970,95972).

DAPOXETINE (Priligy) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of dapoxetine, potentially increasing the effects and adverse effects of dapoxetine.  Details Pharmacokinetic research shows that drinking grapefruit juice 250 mL prior to taking dapoxetine 60 mg can increase the maximum plasma concentration of dapoxetine by 80% and prolong the elimination half-life by 43%. This effect is attributed to the inhibition of both intestinal and hepatic cytochrome P450 3A4 (CYP3A4) by grapefruit (95975).

DEXTROMETHORPHAN (Robitussin DM, others) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.  Details Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism, causing increased dextromethorphan levels (11362).

EMPAGLIFLOZIN (Jardiance) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice may increase the levels and clinical effects of empagliflozin.  Details Animal research suggests grapefruit juice increases the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of empagliflozin, possibly due to inhibition of metabolism by uridine diphosphoglucuronosyl transferase (UGT) (115467). This effect has not been reported in humans.

ERYTHROMYCIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of erythromycin, potentially increasing the effects and adverse effects of erythromycin.  Details Clinical research shows that concomitant use of erythromycin with grapefruit can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of erythromycin, increasing plasma concentrations of erythromycin by 35% (8286).

ESTROGENS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of estrogens, potentially increasing the effects and adverse effects of estrogens.  Details Clinical research shows that grapefruit increases the levels of endogenous and exogenous estrogens by inhibiting cytochrome P450 3A4 (CYP3A4) enzymes (525,526,14858). Grapefruit juice increases exogenously administered 17-beta-estradiol by about 20% in females without ovaries and ethinyl-estradiol in healthy females (525,526,22160).

ETOPOSIDE (VePesid) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of etoposide, potentially decreasing the clinical effects of etoposide.  Details Clinical research shows that grapefruit juice decreases the absorption and plasma concentrations of etoposide. There is some evidence that grapefruit juice co-administered with oral etoposide can reduce levels of etoposide by about 26% (8744). Grapefruit juice seems to inhibit organic anion transporting polypeptide (OATP), which is a drug transporter in the gut, liver, and kidney (7046,17603,17604). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

FEXOFENADINE (Allegra) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can decrease blood levels of fexofenadine, thereby decreasing the clinical effects of fexofenadine.  Details Clinical research shows that grapefruit juice can significantly decrease oral absorption and blood levels of fexofenadine. In one study, consuming a drink containing grapefruit juice 25% decreased bioavailability of fexofenadine by about 24%. Consuming a full-strength grapefruit juice drink reduced bioavailability by 67% (7046). In another study, consuming grapefruit juice 300 mL decreased fexofenadine levels by 42%. Consuming 1200 mL of grapefruit juice reduced levels by 64% (17602). Similarly, drinking grapefruit juice 240 mL decreased the oral bioavailability of fexofenadine by 25% in another pharmacokinetic study (112288). Fexofenadine manufacturer data indicates that concomitant administration of grapefruit juice and fexofenadine results in larger wheal and flare sizes in research models. This suggests that grapefruit also reduces the clinical response to fexofenadine (17603). Grapefruit juice seems to inhibit organic anion transporting polypeptide (OATP), which is a drug transporter in the gut, liver, and kidney (7046,17603,17604,22161). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

FLUVOXAMINE (Luvox) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can increase blood levels of fluvoxamine, potentially increasing the effects and adverse effects of fluvoxamine.  Details Clinical research shows that grapefruit juice inhibits metabolism and increases fluvoxamine levels and peak concentration (17675).

HALOFANTRINE Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of halofantrine, potentially increasing the effects and adverse effects of halofantrine.  Details Clinical research shows that grapefruit juice inhibits cytochrome P450 3A4 (CYP3A4) metabolism, which increases halofantrine levels and peak concentration, as well as a marker of ventricular tachyarrhythmia potential (22129).

HMG-CoA REDUCTASE INHIBITORS ("Statins") Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of statins that are metabolized by cytochrome P450 3A4 (CYP3A4), potentially increasing the effects and adverse effects of these statins. Additionally, grapefruit juice might interfere with the bioavailability of statins that are substrates of organic anion transporting polypeptides (OATP).  Details Clinical research shows that grapefruit juice inhibits metabolism and increases absorption and plasma concentrations of statins that are metabolized by CYP3A4. These include lovastatin (527,11274), simvastatin (3774,7782,22127), and atorvastatin (3227,12179,22126). Keep in mind that there is considerable variability in the effect of grapefruit juice on drug metabolism, so individual patient response is difficult to predict (7777,7781). Some statins, including pravastatin, fluvastatin, pitavastatin, and rosuvastatin, are not metabolized by CYP3A4. However, grapefruit juice might still affect the bioavailability of these statins. These statins are substrates of OATP. Grapefruit juice can inhibit OATP. Therefore, grapefruit juice may reduce the bioavailability or increase drug levels of these statins depending on the type of OATP. However, grapefruit juice affects OATP for only a short time. Therefore, separating drug administration by at least 4 hours is likely to avoid this interaction (3227,12179,17601,22126,91420).

ITRACONAZOLE (Sporanox) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can interfere with itraconazole absorption, although the clinical significance of this interaction is unclear.  Details Clinical research shows that grapefruit juice can affect itraconazole absorption and might increase or decrease itraconazole levels (310,17601,22123).

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can decrease blood levels of levothyroxine, potentially decreasing the effectiveness of levothyroxine.  Details Clinical research shows that grapefruit juice modestly decreases levothyroxine levels by 11% by inhibiting organic anion transporting polypeptide (OATP) (17604,22163). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

LOSARTAN (Cozaar) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of the active metabolite of losartan, potentially decreasing the clinical effects of losartan.  Details Losartan is an inactive prodrug which must be metabolized to its active form, E-3174, to be effective. In one human study, grapefruit juice reduced losartan metabolism, increased losartan AUC, and reduced the AUC of the major active losartan metabolite, E-3174 (1391).

METHADONE (Dolophine) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of methadone, potentially increasing the effects and adverse effects of methadone.  Details Clinical research shows that grapefruit juice inhibits the metabolism of methadone, increasing methadone levels and peak concentrations (17676). In one case, a 51-year-old male taking methadone 90 mg daily and no other medications was found unresponsive. The patient reported drinking grapefruit juice 500 mL daily for 3 days prior to the event. Methadone is a substrate of cytochrome P450 3A4 (CYP3A4), and grapefruit juice-induced inhibition of CYP3A4 is the likely cause of this interaction (102056).

METHYLPREDNISOLONE Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of methylprednisolone, potentially increasing the effects and adverse effects of methylprednisolone.  Details Clinical research shows that grapefruit juice can increase the plasma concentration of orally administered methylprednisolone. Grapefruit juice 200 mL three times daily given with methylprednisolone 16 mg increased methylprednisolone half-life by 35%, peak plasma concentration by 27%, and total area under the curve by 75% (3123).

NADOLOL (Corgard) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice might decrease blood levels of nadolol, potentially decreasing the clinical effects of nadolol.  Details Nadolol is a substrate of organic anion transporting polypeptide 1A2 (OATP1A2) (17603,17604,22161). Some research shows that grapefruit juice and its constituent naringin can inhibit organic anion transporting polypeptides (OATP), which can reduce the bioavailability of OATP substrates (17603,17604,22161,91427). However, preliminary clinical research shows that grapefruit juice containing a low amount of naringin does not significantly affect levels of nadolol (91422). It is not known if grapefruit juice containing higher amounts of naringin reduces the bioavailability of nadolol.

NILOTINIB (Tasigna) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of nilotinib, potentially increasing the effects and adverse effects of nilotinib.  Details Clinical research shows that grapefruit juice inhibits metabolism and increases absorption of nilotinib. Grapefruit juice increases nilotinib levels by 29% and peak concentration by 60% (17677).

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can decrease levels of drugs that are substrates of OATP.  Details In vitro and clinical research show that consuming grapefruit juice inhibits OATP, which reduces the bioavailability of oral drugs that are substrates of OATP. Various clinical studies have shown reduced absorption of OATP substrates when taken with grapefruit, including fexofenadine, acebutolol, aliskiren, celiprolol, levothyroxine, nadolol, and pitavastatin (17603,17604,18101,22126,22134,22161,22163,91420,91427,91428,112288). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

OXYCODONE (Oxycontin) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of oxycodone, potentially increasing the effects and adverse effects of oxycodone.  Details Oxycodone is metabolized by both cytochrome P450 3A4 (CYP3A4) and cytochrome P450 2D6 (CYP2D6). A small clinical study shows that grapefruit juice can increase plasma levels of oral oxycodone about 1.7-fold by inhibiting CYP3A4. While the analgesic effects of oxycodone do not seem to be affected, taking grapefruit juice along with oxycodone may theoretically increase the adverse effects of oxycodone (91423).

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice does not seem to affect renal P-glycoprotein (P-gp). Theoretically, it might inhibit intestinal P-gp, but evidence is conflicting.  Details While most in vitro research shows that grapefruit products inhibit P-gp, (1390,11270,11278,11362,95976), research in humans is less clear. Two small clinical studies in healthy adults using digoxin as a probe substrate show that grapefruit juice does not inhibit P-gp in the kidneys (11277,11282). It is unclear whether this applies to intestinal P-gp, for which digoxin is not considered to be a sensitive probe (105568). Grapefruit juice has been shown to reduce levels of fexofenadine (7046,17602,112288), and increase levels of quinidine (5067,22121). However, as both of these drugs are also substrates of other enzymes and transporters, it is unclear what role, if any, intestinal P-gp has in these findings.

PITAVASTATIN (Livalo) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of pitavastatin, potentially increasing the effects and adverse effects of pitavastatin.  Details Pharmacokinetic research shows that taking grapefruit juice with pitavastatin 2-4 mg can increase blood levels of pitavastatin by 13% to 14%. Unlike simvastatin and atorvastatin, pitavastatin is not significantly metabolized by cytochrome P450 3A4 (CYP3A4) enzymes. Grapefruit juice appears to increase levels of pitavastatin by inhibiting its uptake by organic anion transporting polypeptide 1B1 (OATP1B1) into hepatocytes for metabolism and clearance from the body (22126,91420). Grapefruit juice seems to increase levels of pitavastatin to a greater degree in patients homozygous for a specific polymorphism (388A>G) in the OATP1B1 gene compared to those heterozygous for this polymorphism (91420).

PRASUGREL (Effient) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of the active metabolite of prasugrel, thereby decreasing the antiplatelet effect of prasugrel.  Details Prasugrel is a prodrug that is metabolized by cytochrome P450 3A4 (CYP3A4) into its active metabolite. A small pharmacokinetic study in healthy volunteers shows that drinking grapefruit juice 200 mL three times daily for 4 days and taking a single dose of prasugrel 10 mg with an additional 200 mL of grapefruit juice on day 3, results in a 49% lower peak plasma level and a 26% lower overall plasma exposure to the active metabolite when compared with drinking water. However, despite the reduced exposure, platelet aggregation seems to be reduced by an average of only 5% (105567). The clinical significance of this interaction is unclear.

PRAZIQUANTEL (Biltricide) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of praziquantel, potentially increasing the effects and adverse effects of praziquantel.  Details Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of praziquantel. Plasma concentrations of praziquantel can increase by as much as 160% when administered with 250 mL of commercially available grapefruit juice (8282).

PRIMAQUINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice may increase blood levels of primaquine, potentially increasing the effects and adverse effects of primaquine.  Details Clinical research shows that grapefruit juice increases the bioavailability of primaquine by approximately 20% (22130). The clinical significance of this interaction is not clear.

QT INTERVAL-PROLONGING DRUGS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit or grapefruit juice, especially if consumed in large amounts, can cause additive QT interval prolongation when taken with QT interval-prolonging drugs, potentially increasing the risk of ventricular arrhythmias.  Details Clinical research in healthy volunteers shows that drinking 6 liters of grapefruit juice over 6 hours prolonged the QTc by a peak amount of 14 milliseconds (ms). This prolongation was similar to the QT prolongation caused by the drug moxifloxacin. In individuals with long QT syndrome, a smaller dose of grapefruit juice, 1.5 liters, resulted in a greater peak QTc prolongation of about 30 ms (100249). The effect of smaller quantities of grapefruit juice on the QT interval is unclear.

QUETIAPINE (Seroquel) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice may increase blood levels of quetiapine, increasing the effects and adverse effects of quetiapine.  Details Quetiapine is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4 (3227,3774,8283,8285,8286,22129,91427,104190). In one case report, a healthy 28-year-old female with bipolar disorder stabilized on quetiapine 800 mg daily presented with quetiapine toxicity considered to be related to consuming a gallon of grapefruit juice over the past 24 hours (108848).

QUINIDINE Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can alter blood levels of quinidine, potentially increasing or decreasing the clinical effects of quinidine.  Details Clinical research shows that grapefruit juice decreases quinidine absorption, clearance, and metabolism, and prolongs the half-life by about 20% (5067,22121).

RIVAROXABAN (Xarelto) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice may increase the concentration and clinical effects of rivaroxaban.  Details Rivaroxaban is metabolized partially by cytochrome P450 3A4 (CYP3A4). Grapefruit juice can inhibit CYP3A4. Animal research shows that grapefruit juice increases the peak plasma concentration (Cmax) of rivaroxaban by about four-fold, without increasing the area under the drug concentration-time curve (AUC) (115468).

SAQUINAVIR (Fortovase, Invirase) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of saquinavir, potentially increasing the effects and adverse effects of saquinavir.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of saquinavir (3773,22132).

SCOPOLAMINE (Transderm Scop) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of scopolamine, potentially increasing the effects and adverse effects of scopolamine.  Details Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of scopolamine, increasing its absorption and plasma concentrations. Oral bioavailability of scopolamine can increase by 30% when administered with 150 mL of grapefruit juice (8284).

SERTRALINE (Zoloft) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can increase blood levels of sertraline, potentially increasing the effects and adverse effects of sertraline.  Details Clinical research shows that grapefruit juice inhibits the cytochrome P450 3A4 (CYP3A4) metabolism of sertraline, increasing blood levels of sertraline (22122).

SILDENAFIL (Viagra) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of sildenafil, potentially increasing the effects and adverse effects of sildenafil.  Details Clinical research shows that grapefruit juice inhibits cytochrome P450 3A4 (CYP3A4) metabolism of sildenafil, increasing its absorption and plasma concentrations. Oral bioavailability of sildenafil can increase by 23% when administered with 500 mL of commercially available grapefruit juice (8283).

SUNITINIB (Sutent) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Unlikely •  Level of Evidence = B Grapefruit juice may slightly increase blood levels of sunitinib, potentially increasing the effects and adverse effects of sunitinib.  Details Sunitinib is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit and grapefruit juice can inhibit CYP3A4 and increase levels of some drugs metabolized by this enzyme. One small clinical study shows that drinking 200 mL of grapefruit juice three times daily can increase the bioavailability of sunitinib by 11% (91429). While this effect is unlikely to be clinically significant, patients should use caution when using grapefruit along with sunitinib. Dose adjustments may be necessary.

TACROLIMUS (Prograf) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of tacrolimus, potentially increasing the effects and adverse effects of tacrolimus.  Details Clinical research shows that drinking grapefruit juice 200 mL daily while taking tacrolimus 3 mg daily increases the trough blood concentration of tacrolimus by approximately 3-fold in patients with connective tissue diseases (95974). A single case has also reported a 10-fold increase in tacrolimus trough levels after the ingestion of grapefruit juice over 3 days (22122). This effect is attributed to the inhibition of cytochrome P450 3A4 (CYP3A4) by grapefruit (95974).

TADALAFIL (Cialis) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice might increase blood levels of tadalafil, potentially increasing the effects and adverse effects of tadalafil.  Details Animal research shows that grapefruit juice increases tadalafil serum concentrations and overall exposure, likely through inhibition of cytochrome P450 3A4 enzymes (104189).

TALINOLOL Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice might decrease blood levels of talinolol, potentially decreasing the clinical effects of talinolol.  Details Clinical research suggests that grapefruit juice reduces talinolol bioavailability, likely by inhibiting intestinal uptake (22135). The clinical significance of this effect is unclear.

TERFENADINE (Seldane) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of terfenadine, potentially increasing the effects and adverse effects of terfenadine.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of terfenadine (530,22124,22125). The mechanism of action is unclear.

THEOPHYLLINE Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of theophylline, potentially decreasing the effectiveness of theophylline.  Details Clinical research shows that grapefruit juice seems to modestly decrease theophylline levels when given concurrently with sustained-release theophylline (11013). The mechanism of this interaction is unknown.

TICAGRELOR (Brilinta) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of ticagrelor, thereby increasing the effects and adverse effects of ticagrelor.  Details Ticagrelor is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. A small clinical study shows that taking grapefruit juice with ticagrelor increases blood levels of ticagrelor more than two-fold and increases the antiplatelet activity of ticagrelor (91418). Additionally, animal research shows that grapefruit juice increases peak plasma concentration (Cmax) and the area under the drug concentration-time curve (AUC) of ticagrelor (115468).

TOLVAPTAN (Samsca) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of tolvaptan, potentially increasing the effects and adverse effects of tolvaptan.  Details Tolvaptan is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. A small clinical study shows that grapefruit juice can increase the bioavailability and blood levels of tolvaptan by approximately 1.6-fold for up to 16 hours (91426).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, drinking large amounts of grapefruit juice might increase the effects and adverse effects of warfarin.  Details In one case report, a patient experienced significantly increased international normalized ratio (INR) associated with consumption of 50 ounces of grapefruit juice daily (12061). However, smaller amounts of grapefruit juice might not be a problem. In a small clinical trial, consumption of 24 ounces of grapefruit juice daily for one week had no effect on INR in males treated with warfarin (12063).

(Read more about GRAPEFRUIT)

ITRACONAZOLE (Sporanox) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking itraconazole capsules or tablets with a beverage containing lemon might increase the levels and clinical effects of itraconazole.  Details In one case report, dissolving itraconazole tablets in a small amount of specific beverages containing lemon prior to administration increased the level of itraconazole in a lung transplant patient. In this case, the increased bioavailability was desirable and was likely due to improved tablet dissolution in the acidic beverage (110781).

(Read more about LEMON)

BISPHOSPHONATES Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking phosphate salts with bisphosphonates might increase the risk of hypocalcemia.  Details Combining bisphosphonates and phosphate can cause hypocalcemia. In one report, hypocalcemic tetany developed in a patient taking alendronate (Fosamax) who received a large dose of phosphate salts as a pre-operative laxative (14589).

ERDAFITINIB (Balversa) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = A Taking erdafitinib with phosphate salts increases the risk of hyperphosphatemia.  Details Erdafitinib increases phosphate levels. It is recommended that patients taking erdafitinib restrict phosphate intake to no more than 600-800 mg daily (104470).

FUTIBATINIB (Lytgobi) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = A Taking futibatinib with phosphate salts increases the risk of hyperphosphatemia.  Details Futibatinib can cause hyperphosphatemia, as reported in 88% of patients in clinical studies. In addition, 77% of patients in clinical studies required use of a phosphate binder to manage hyperphosphatemia. Phosphate salts should generally be avoided by people taking this medication (112912).

(Read more about PHOSPHATE SALTS)

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Unlikely •  Level of Evidence = B In vitro, tangeretin, a constituent of tangerine, induces a 52% increase in the metabolism of midazolam by cytochrome P450 3A4 (CYP3A4) (28609). This suggests that tangeretin may stimulate CYP3A4 activity. However, in humans, drinking tangerine juice 200 mL slightly delayed the absorption, but did not affect the metabolism, of midazolam, a CYP3A4 substrate (28609). Theoretically, tangerine juice might increase CYP3A4 activity and decrease levels of drugs metabolized by this enzyme. However, this effect is unlikely.  Details Some drugs metabolized by CYP3A4 include amitriptyline (Elavil), amiodarone (Cordarone), citalopram (Celexa), felodipine (Plendil), lansoprazole (Prevacid), ondansetron (Zofran), prednisone (Deltasone, Orasone), sertraline (Zoloft), sibutramine (Meridia), and many others.

(Read more about TANGERINE)

General ...Orally and intravenously, calcium is well-tolerated when used appropriately.
Most Common Adverse Effects:
Orally: Belching, constipation, diarrhea, flatulence, and stomach upset.
Serious Adverse Effects (Rare):
Orally: Case reports have raised concerns about calciphylaxis and kidney stones.

Cardiovascular ...There has been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these results, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Many of these trials also only included postmenopausal females. Other analyses report conflicting results, and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of CVD, CHD, or MI (93533,107231). Also, the association between calcium supplementation and CVD, CHD, or MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482). To minimize the possible risk of CVD, CHD, or MI, advise patients not to consume more than the recommended daily intake of 1000-1200 mg and to consider total calcium intake from both dietary and supplemental sources (17484). While dietary intake of calcium is preferred over supplemental intake, advise patients who require calcium supplements to take calcium along with vitamin D, as this combination does not appear to be associated with an increased risk of MI (93533).
Rarely, calcium intake can increase the risk of calciphylaxis, which usually occurs in patients with kidney failure. Calciphylaxis is the deposition of calcium phosphate in arterioles, which causes skin ulcers and skin necrosis. In a case report, a 64-year-old female with a history of neck fracture, sepsis, and ischemic colitis presented with painful leg ulcers due to calciphylaxis. She discontinued calcium and vitamin D supplementation and was treated with sodium thiosulfate and supportive care (95816).

Gastrointestinal ...Orally, calcium can cause belching, flatulence, nausea, gastrointestinal discomfort, and diarrhea (1824,1843,12950,38803). Although constipation is frequently cited as an adverse effect of calcium, there is no scientific substantiation of this side effect (1824,1843,1844,1845,12950,38978). Calcium carbonate has been reported to cause acid rebound, but this is controversial (12935,12936).

Oncologic ...There is some concern that very high doses of calcium might increase the risk of prostate cancer. Some epidemiological evidence suggests that consuming over 2000 mg/day of dietary calcium might increase the risk for prostate cancer (4825,12949). Additional research suggests that calcium intake over 1500 mg/day might increase the risk of advanced prostate cancer and prostate cancer mortality (14132). Consumption of dairy products has also been weakly linked to a small increase in prostate cancer risk (98894). However, contradictory research suggests no association between dietary intake of calcium and overall prostate cancer risk (14131,14132,104630). More evidence is needed to determine the effect of calcium, if any, on prostate cancer risk.

Renal ...Kidney stones have been reported in individuals taking calcium carbonate 1500 mg daily in combination with vitamin D 2000 IU daily for 4 years (93943).

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General ...Orally, echinacea is well tolerated.
Most Common Adverse Effects:
Orally: Abdominal pain, constipation, diarrhea, heartburn, nausea and vomiting, rashes, and stomach upset.
Serious Adverse Effects (Rare):
Orally: Severe allergic reactions and hepatitis have been reported.

Dermatologic ...Itching, urticaria, tingling, and allergic rashes have been reported with various echinacea preparations (8225,12355,17519,20059,20077,101592,111530,111540). In a study of children aged 2-11 years, rash occurred in about 7% of children treated with an extract of the above-ground parts of E. purpurea (EC31J2, Echinacin Saft, Madaus AG), compared with about 3% of those treated with placebo (4989,95652). There is concern that allergic reactions could be severe in some children. The Medicines and Healthcare Products Regulatory Agency in the United Kingdom (UK) recommends against the use of oral echinacea products in children under 12 years of age due to this risk of allergic reaction (18207). However, another study in children 4-12 years old shows that a specific E. purpurea product (Echinaforce Junior, A. Vogel) did not cause allergic or urticarial reactions more frequently than vitamin C (105719).

Gastrointestinal ...Gastrointestinal adverse effects include nausea and vomiting, abdominal pain, stomach upset, heartburn, diarrhea, and constipation (10802,11970,12355,13419,17519,20059,48680,105719,106626). An unpleasant taste, dry mouth, and burning, tingling or numbness of the tongue also occur (11970,12355,17519,20059,20070,20077).

Hematologic ...A 51-year-old female presented with leukopenia after taking echinacea 450 mg three times daily for 2 months, along with ginkgo biloba, multivitamins, and calcium. Her leukocyte count recovered upon stopping these supplements, but dropped again when she restarted echinacea alone about a year later. The problem resolved when echinacea was stopped permanently (48533). A 32-year-old male presented with severe thrombotic thrombocytopenic purpura (TTP) about 2 weeks after using an extract of E. pallida to treat a cold. He required admission to an intensive care unit and extensive plasmapheresis. The authors speculate that immunostimulant effects of echinacea induced or exacerbated the TTP (48572).

Hepatic ...Although uncommon, cases of echinacea-induced hepatitis have been reported. One case report describes acute cholestatic autoimmune hepatitis in a 45-year-old male who had been taking an echinacea root extract 1500 mg daily for about 2 weeks. He presented with significantly elevated liver function tests (LFTs), elevated immunoglobulin G (IgG) levels, and a positive test for anti-smooth muscle antibodies, indicating an autoimmune process. Elevated LFTs and IgG levels returned to normal within one month of stopping echinacea (17518). Another case report describes acute cholestatic hepatitis in a 44-year-old male who had taken echinacea root tablets 600 mg daily for 5 days to treat flu-like symptoms. He presented with elevated LFTs, prothrombin time, and international normalized ratio (INR). His condition gradually improved after stopping echinacea, and his LFTs normalized within 3 months (91528).
Seven cases of hepatitis associated with echinacea use were reported to the Australian Adverse Drug Reactions Advisory Committee between 1979 and 2000, but specific details are lacking (8225).
One case report describes acute liver failure in a 2 year-old child who had been given about 100 mg of echinacea daily for 2 weeks. The patient presented with jaundice, diarrhea, lethargy, anorexia, and significantly elevated LFTs. A liver biopsy showed hepatocyte swelling, spotty necrosis, and inflammatory infiltrate with eosinophils. A full recovery was made over a 2-week period (88166).

Immunologic ...Allergic reactions, including urticaria, runny nose, dyspnea, bronchospasm, acute asthma, angioedema, and anaphylaxis, have been reported with various echinacea preparations (638,1358,8225). Atopic individuals and those sensitive to other members of the Asteraceae family (ragweed, chrysanthemums, marigolds, daisies) seem to be at higher risk for these reactions (1358,8225).
A case report describes a 36-year-old female who presented with muscle weakness, electrolyte abnormalities, renal tubular acidosis, fatigue, and dry mouth and eyes after taking echinacea, kava, and St. John's Wort for 2 weeks., She also had a positive antinuclear antibody (ANA) test, with elevated anti-dsDNA antibodies SSA and SSB. Sjogren syndrome was diagnosed; the authors hypothesize that it may have been triggered by the immunostimulant effects of echinacea (10319). A 55-year-old male with a history of pemphigus vulgaris in remission for about a year experienced a flare of the disease after taking an echinacea supplement for one week. After stopping echinacea, medical treatment resulted in partial control of the disease (12171). Another case report describes a 58-year-old male who presented with marked eosinophilia and elevated immunoglobulin E (IgE) levels while taking an echinacea supplement. He required prednisone therapy until he stopped taking echinacea 3 years later, at which time his eosinophils and IgE normalized (48623). A 41-year-old male experienced four episodes of erythema nodosum, each occurring after he had taken echinacea for early symptoms of influenza. After stopping echinacea, he had no further exacerbations of erythema nodosum, suggesting that it had been triggered by the immunostimulant effects of echinacea (7057).

Musculoskeletal ...Reports of arthralgia and myalgia have been associated with echinacea (13418).

Neurologic/CNS ...Headache has been reported in people taking various echinacea preparations orally (3282,11970,17519,20059,20064). Dizziness has also been reported (3282,8225,11970). In one study using an alcoholic extract of the above-ground parts of E. purpurea (EC31J0, Echinacin, Madaus AG), somnolence and a tendency to aggressiveness were reported (3282).

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General ...Orally, grapefruit and grapefruit juice are generally well tolerated.
Serious Adverse Effects (Rare):
Orally: Allergic reactions in sensitive individuals have been reported. When large quantities are consumed, arrhythmias, mineralocorticoid excess, QT prolongation, and pseudohyperaldosteronism have been reported. There is also some concern for increased breast cancer risk with grapefruit consumption.

Cardiovascular ...Orally, consumption of pink grapefruit juice 1000 mL can cause QT prolongation and cause arrhythmias in healthy patients and worsen arrhythmias in cardiomyopathy patients (13031,91424).

Endocrine ...Orally, high doses of grapefruit juice have been observed to cause pseudohyperaldosteronism and mineralocorticoid excess (53340,53346).

Gastrointestinal ...In a case report, grapefruit juice held against the teeth resulted in enamel and tooth surface loss (53368).

Immunologic ...Orally, grapefruit can cause allergic sensitization characterized by eosinophilic gastroenteritis, urticaria, and generalized pruritus (53351,53360).

Oncologic ...Preliminary population research shows that postmenopausal adults who consume a quarter or more of a whole grapefruit daily have a 25% to 30% increased risk of developing breast cancer (14858). Grapefruit is a potent inhibitor of cytochrome P450 3A4, which metabolizes estrogen. Consuming large amounts of grapefruit might significantly increase endogenous estrogen levels and therefore increase the risk of breast cancer. More evidence is needed to validate these findings. Until more is known, advise patients to consume grapefruit in moderation.

Renal ...In population research, consumption of 240 mL/day of grapefruit juice is associated with an increased risk of kidney stones (4216,53372).

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General ...Orally, lemon is well tolerated in amounts commonly found in foods. A thorough evaluation of safety outcomes has not been conducted on the use of larger amounts.
Most Common Adverse Effects:
Orally: Epigastralgia and heartburn with the regular consumption of fresh lemon juice.

Dermatologic ...Topically, the application of lemon oil might cause photosensitivity, due to furocoumarin derivative content. This occurs most often in fair-skinned people (11019).

Gastrointestinal ...Orally, fresh lemon juice, taken as 60 mL twice daily, has been reported to cause gastrointestinal disturbances in 37% of patients in one clinical trial, compared with 8% of patients in the placebo group. Specifically, of the patients consuming lemon juice, 21% experienced heartburn and 8% experienced epigastralgia, compared to 1% and 3%, respectively, in the placebo group (107489).

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General ...Orally, intravenously, and rectally, phosphate salts are generally well tolerated when used appropriately and/or as prescribed.
Most Common Adverse Effects:
Orally: Abdominal pain, anal irritation, bloating, diarrhea, headache, gastrointestinal irritation, hyperphosphatemia, hypocalcemia, malaise, nausea, sleep disturbance, and vomiting.
Rectally: Hyperphosphatemia and hypocalcemia.
Serious Adverse Effects (Rare):
Orally: Extraskeletal calcification.

Cardiovascular ...Orally, a case of allergic acute coronary syndrome e., Kounis syndrome) is reported in a 43-year-old female after ingesting a specific sodium phosphate laxative product (Travad oral). She presented with maculopapular rash that progressed to anaphylaxis and a non-ST elevation acute coronary syndrome. The patient recovered after hospitalization for 3 days with medical management (112894).

Gastrointestinal ...Orally, phosphate salts can cause gastrointestinal irritation, nausea, abdominal pain, bloating, anal irritation, and vomiting (15,2494,2495,2496,2497,93846,93848,93850,93851,93853,107008). Sodium and potassium phosphates can cause diarrhea (15). Aluminum phosphate can cause constipation (15). A large comparative study shows that, when taken orally as a bowel preparation for colonoscopy, sodium phosphate is associated with gastric mucosal lesions in about 4% of patients (93868).

Neurologic/CNS ...Orally, phosphate salts can commonly cause malaise (93846). Headaches and sleep disturbance may also occur (93848,93851).

Renal ...Orally, use of sodium phosphate for bowel cleansing has been associated with an increased risk of acute kidney injury in some patients (93863). However, a pooled analysis of clinical research suggests that results are not consistent for all patients (93864). Some evidence suggests that female gender, probably due to lower body weight, iron-deficiency anemia, dehydration, and chronic kidney disease are all associated with an increased risk of sodium phosphate-induced kidney dysfunction (93865).

Other ...Orally, phosphate salts can cause fluid and electrolyte disturbances including hyperphosphatemia and hypocalcemia, and extraskeletal calcification. Potassium phosphates can cause hyperkalemia. Sodium phosphates can cause hypernatremia and hypokalemia (15,2494,2495,2496,2497,107008).
Rectally, phosphate salts can cause fluid and electrolyte disturbances including hyperphosphatemia and hypocalcemia (15,112922).
Deaths related to intake of oral or rectal phosphate salts are rare and most have occurred in infants and are related to overdose (93866). However, death has also been reported in elderly patients using sodium phosphate enemas, mainly at standard doses of 250 mL (93867).

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General ...Orally, very few adverse effects have been reported with the medicinal use of tangerine. However, a thorough evaluation of safety outcomes has not been conducted.
Topically, contact dermatitis has been associated with tangerine essential oil (28610).

Dermatologic ...According to one case report, the essential oil of tangerine in a fragrance has been associated with contact dermatitis (28610).

Gastrointestinal ...In a case report, a 5 year-old patient had a phytobezoar that included tangerine residues (28611). In another case report, orange and tangerine caused obstruction of the small intestine (28612).

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