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There is insufficient reliable information available about the effectiveness of betony.

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POSSIBLY EFFECTIVE

• Menopausal symptoms. Oral black cohosh seems to modestly improve some physical symptoms of menopause, but it is unclear if black cohosh improves mood-related symptoms. Details: A meta-analysis of 22 studies in adults with menopause shows that taking black cohosh extract alone or in combination with other herbal medicines for 4-52 weeks improves overall menopausal symptoms, hot flashes, and somatic symptoms but not anxiety or depressive symptoms when compared with placebo (111659). Meta-analyses of 20 clinical trials that assessed black cohosh shows that overall black cohosh is not superior to placebo and is inferior to hormonal therapy for reducing hot flash frequency and symptoms of menopause (89467,92661). The most consistent evidence is for a specific isopropanolic extract of black cohosh (Remifemin, Phytopharmica/Enzymatic Therapy). When taken in doses of 40-127 mg daily for up to 12 weeks it reduces menopausal symptoms and hot flash frequency when compared with placebo (9437,13143,13184,14423,15889,35824,35853,35904,35964). It also seems to be comparable to hormonal therapy, including low-dose transdermal estradiol (Estraderm) 25 mcg every 7 days (13184), tibolone 2.5 mg daily (15889,35904), or conjugated equine estrogens (Premarin) 0.625 mg daily (35964). Additionally, the Spanish Menopause Society (AEEM) states that most current evidence shows that this specific black cohosh extract, at a dose of 40 mg daily, is most effective at improving mood and treating vasomotor symptoms such as reducing night sweats and hot flushes, particularly in those with intense hot flushes. In women with natural menopause, taking this extract at a dose of 8-128 mg for 3-6 months treats vasomotor symptoms more effectively than placebo and similarly to low-dose transdermal estrogen or tibolone. Additionally, black cohosh improves depression, anxiety, sleep quality, vaginal atrophy, and bone metabolism but does not seem to clinically impact endometrium thickness, cognitive function, skin, or lipid profiles (111634). Research using other formulations of black cohosh is less consistent. One commercial black cohosh extract CR BNO 1055 (Klimadynon/Menofem, Bionorica AG) 40 mg daily in 1-2 divided doses for 60-90 days does not reduce menopausal symptoms when compared with control groups (10987,13169,35908). Other clinical research shows that taking a different commercial black cohosh extract (Remixin, Mikro-Gen) 40 mg daily for 6 months reduces hot flashes and night sweats when compared with fluoxetine 20 mg daily (35852). However, the high dropout rate and lack of placebo group limit the reliability of these findings. Studies using non-commercial black cohosh extracts have been mostly negative. In one study, taking a black cohosh extract 6.5 mg daily for 12 weeks did not reduce hot flashes or symptom rating scores when compared with placebo; however, a subgroup of patients with at least moderate symptoms appeared to have improvement in some symptoms (14424). In another study, taking black cohosh ethanolic extract 160 mg daily did not reduce frequency of hot flashes or other vasomotor symptoms after 12 months of treatment (15158). Taking another black cohosh extract 128 mg daily for 12 months was significantly less effective than conjugated equine estrogens (Premarin) in reducing hot flashes and night sweats, and was also less effective than placebo at some time points during the study (17091). Black cohosh has also been evaluated in patients with cancer treatment-induced menopausal symptoms. A small observational study in adults with menopausal symptoms secondary to tamoxifen therapy for breast cancer suggests that taking a dry extract of black cohosh 20 mg improves climacteric symptoms when compared with placebo (111635). The validity of these effects is limited by a small sample size and lack of a comparator group. Preliminary clinical trials have also evaluated black cohosh in combination with numerous other herbal ingredients (15037,15893,19552,35853,53707,103269). Several trials have shown a benefit with some combinations when compared with baseline or placebo, but these combinations have not been compared with black cohosh alone. It is unclear whether the effects are due to black cohosh, other ingredients, or the combinations.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there has been interest in using topical black cohosh for acne, there is insufficient reliable information about the clinical effects of black cohosh for this purpose.
• Anxiety. Black cohosh does not appear to be effective for treating anxiety in postmenopausal patients. Details: Preliminary clinical research in postmenopausal patients shows that taking a black cohosh extract, 64 mg daily for 2 weeks, then gradually increasing to 128 mg daily for a total of 12 weeks, does not improve anxiety as measured on the Hamilton Anxiety Rating (HAM-A) scale, when compared with placebo (35897).
• Breast cancer. It is unclear if oral black cohosh is beneficial for breast cancer treatment or prevention. Details: One observational study suggests that the use of black cohosh supplements is associated with a decreased risk of breast cancer (35841); however, other population-based studies found no difference (17412,35896). In females diagnosed with breast cancer, one observational study found that black cohosh extract was associated with prolonged disease-free survival (35845). A small observational study in patients with ductal carcinoma in situ (DCIS) suggests that taking isopropanolic black cohosh extract 20 mg twice daily for 2-6 weeks prior to breast surgery does not impact breast cancer cellular proliferation, tumor volume, invasive disease upgrade rates, or hormone levels including estradiol, and follicle-stimulating hormone when compared to baseline (111714). The validity of these effects is limited by a lack of a comparator group.
• Breast cancer-related hot flashes. Evidence for the use of oral black cohosh for hot flashes associated with breast cancer is conflicting. Details: Preliminary open-label trials show that taking black cohosh extracts can reduce hot flashes in females with a history of breast cancer (13169,14423). However, higher-quality randomized controlled trials show that black cohosh does not reduce hot flashes in these patients (7054,15161).
• Cardiovascular disease (CVD). It is unclear if oral black cohosh reduces the risk of CVD. Details: Preliminary clinical research in postmenopausal adults shows that taking a specific black cohosh extract called CR BNO 1055 (Klimadynon Uno, Bionorica) 40 mg daily, in conjunction with endurance exercise, for 10 weeks does not reduce cardiovascular disease risk measured by the Framingham Risk score when compared with endurance exercise or light exercise alone (35908).
• Cognitive function. It is unclear if oral black cohosh is beneficial for improving cognitive function in postmenopausal patients. Details: In one preliminary clinical trial, taking a black cohosh extract 128 mg daily for 12 months did not significantly improve performance on memory and attention tests when compared with placebo in postmenopausal patients (19553).
• Cough. Although there has been interest in using oral black cohosh for cough, there is insufficient reliable information about the clinical effects of black cohosh for this purpose.
• Dysmenorrhea. Although there has been interest in using oral black cohosh for dysmenorrhea, there is insufficient reliable information about the clinical effects of black cohosh for this purpose.
• Infertility. It is unclear if oral black cohosh is beneficial for female infertility. Details: One small clinical study in patients with unexplained infertility shows that taking black cohosh rhizome dry extract (Klimadynon, Bionorica) 120 mg on days 1-12 of the menstrual cycle, plus clomiphene citrate 150 mg daily on days 3-7, increases the pregnancy rate by 23% when compared with clomiphene citrate alone (35858). Another small clinical study in patients with unexplained infertility shows that taking black cohosh (Klimadynon, Bionorica) 120 mg plus clomiphene citrate 150 mg results in similar pregnancy rates when compared with ethinyl estradiol 100 mcg plus clomiphene citrate (35902).
• Insect repellent. Although there has been interest in using topical black cohosh as an insect repellent, there is insufficient reliable information about the clinical effects of black cohosh for this purpose.
• Migraine headache. Oral black cohosh has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In one preliminary clinical trial, taking one tablet of a phytoestrogen formulation containing black cohosh extract 25 mg, soy extract 75 mg, and dong quai extract 50 mg twice daily for 24 weeks reduced the frequency of menstrual migraines when compared with placebo (35797).
• Osteoarthritis. Oral black cohosh has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a specific combination product containing black cohosh 35 mg per tablet, with white willow bark, sarsaparilla, poplar bark, and guaiacum resin (Reumalex, Gerard House Ltd.), two tablets daily for 2 months improves pain when compared with placebo in patients with osteoarthritis. However, no improvement in joint function was found (35946).
• Osteoporosis. There is contradictory evidence on the benefit of black cohosh for osteoporosis treatment or prevention. Details: In one preliminary clinical trial, postmenopausal patients taking specific black cohosh products (Klimadynon/Menofem, Bionorica AG; Remifemin, Schaper & Brümmer) 40 mg daily for 12 weeks had increased levels of bone-specific alkaline phosphatase (bALP), which is a marker of bone formation (14330,35865). However, in another clinical trial, bone mineral density was no different in patients taking a specific black cohosh extract (Klimadynon/Klimadynon Uno/Menofem, Bionorica) 40 mg daily for 12 months when compared with two control groups (35908). It is not known if these black cohosh products can decrease the risk of fracture.
• Parturition. It is unclear whether oral black cohosh is beneficial or safe for labor induction. Details: It has been reported that as many as 45% of nurse-midwives have used black cohosh to induce labor in pregnant adults at term (1122). However, there is no reliable clinical evidence that black cohosh is safe or effective for this use (15035).
• Polycystic ovary syndrome (PCOS). It is unclear if oral black cohosh is beneficial for improving fertility in patients with PCOS. Details: A small clinical study in patients with PCOS and a history of infertility shows that taking black cohosh 10 mg twice daily for 10 days along with clomiphene citrate 50 mg twice daily for 5 days, both starting on the second day of the menstrual cycle, does not increase endometrial thickness or the size or number of mature follicles when compared with clomiphene citrate alone (107905). Pregnancy and live birth rates were not evaluated in this study.
• Premenstrual syndrome (PMS). Although there has been interest in using oral black cohosh for PMS, there is insufficient reliable information about the clinical effects of black cohosh for this purpose.
• Rheumatoid arthritis (RA). Oral black cohosh has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with RA shows that taking a specific combination product containing black cohosh 35 mg per tablet, with white willow bark, sarsaparilla, poplar bark, and guaiacum resin (Reumalex, Gerard House Ltd.) two tablets daily for 2 months improves pain when compared with placebo. However, no improvement in joint function was observed (35946).
• Sexual dysfunction. It is unclear if oral black cohosh is beneficial for improving sexual dysfunction. Details: A small observational study in adults with breast cancer on tamoxifen suggests that taking a dry extract of black cohosh 20 mg is associated with improvements in sexual response scores, which include sexual parameters such as desire, lubrication, orgasm, satisfaction, and pain but not arousal when compared to baseline (111635). The validity of these effects is limited by a small sample size and the lack of a comparator group.
• Warts. Although there has been interest in using topical black cohosh for warts, there is insufficient reliable information about the clinical effects of black cohosh for this purpose. More evidence is needed to rate black cohosh for these uses.

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LIKELY EFFECTIVE

• Diabetic neuropathy. Applying a specific prescription patch containing capsaicin 8% or a specific cream containing capsaicin 0.075% can reduce pain in diabetic neuropathy. Details: Clinical research has evaluated the use of a specific patch (Qutenza, NeurogesX Inc.) containing capsaicin 8%, which is approved as a prescription medication by the US Food and Drug Administration (FDA) for the treatment of diabetic peripheral neuropathy. The research in this population shows that a single application of the patch on the painful parts of the feet for 30-90 minutes following pretreatment with topical anesthetics reduces pain for up to 12 weeks when compared with placebo (40719,96453). Patients using the patch experience reduced sleep interference and an average 28% reduction in pain, compared with a 21% reduction with placebo. Additionally, 50% of patients receiving the patch experience pain relief within 19 days, compared to 72 days for those receiving placebo (96453). A meta-analysis of the available clinical research for diabetic peripheral neuropathy found that one-time application of this patch is equally effective to duloxetine 20-120 mg daily, pregabalin 75-600 mg daily, and gabapentin 300-3600 mg daily in producing a 30% or 50% pain reduction. The dose of oral medication used in the evaluated studies did not impact the comparative efficacy of the capsaicin patch (96450). Other clinical research shows that applying cream containing capsaicin 0.075% four times daily for 8 weeks reduces pain intensity when compared with placebo in patients with diabetic peripheral neuropathy (40547,40592,40607). A meta-analysis of clinical research shows that applying cream containing capsaicin 0.075% reduces pain similarly to 5% lidocaine-medicated plaster (40674). Topical cream containing capsaicin 0.075% (Zostrix-HP, Link Medical Products Pty Ltd.) is FDA-approved as an over-the-counter (OTC) medication for this indication (272). However, applying a capsaicin lotion less frequently or with a lower concentration of capsaicin does not seem to be beneficial. A small clinical study in patients with diabetic neuropathy shows that applying a specific lotion (Capsika-75 lotion, Bangkok Drug Company) containing capsaicin 0.075% three times daily for 8 weeks improves pain to a similar degree as a placebo lotion (102277). This study was limited by a high dropout rate, high placebo effect, and poor adherence to therapy. Furthermore, cream or gel (such as Capsika-25 gel, Bangkok Drug Company) containing lower amounts of capsaicin do not appear to be effective for reducing diabetic peripheral neuropathy pain (92984).
• Pain (chronic). Topical cream containing capsaicin can reduce chronic pain associated with various conditions. Topical capsaicin is FDA-approved for this use. Details: Several clinical studies show that topically applying cream containing capsaicin, the active capsicum constituent, 0.05% to 0.075% temporarily relieves chronic pain from rheumatoid arthritis, osteoarthritis, back pain, jaw pain, psoriasis, and neuropathic conditions (12401,17701). Capsaicin, used in topical preparations, is FDA-approved for these uses (272). It can take up to 14 days for the full analgesic effect. For neuropathic pain, the number needed to treat using capsaicin 0.075% for eight weeks is 5.7 (12401). For musculoskeletal pain, for every 8.1 patients treated with capsaicin 0.025%, 1 patient would achieve at least a 50% reduction in pain (12401). Also, applying capsaicin 0.05% (Finalgon CPD Warmecreme) three times daily for 21 days seems to cause a 49% reduction in chronic soft tissue pain when compared with placebo (17701).
• Postherpetic neuralgia. Applying a specific prescription patch containing capsaicin can reduce postherpetic neuralgia pain, especially in patients with the lowest pain scores. Details: Clinical research has evaluated the use of a specific patch (Qutenza, NeurogesX Inc.) containing capsaicin 8%, which is approved as a prescription medication by the US Food and Drug Administration (FDA) for the treatment of postherpetic neuralgia. Research in this population shows that applying a single patch for 60-90 minutes reduces average pain over 24 hours by 27% to 37% for up to 12 weeks, compared to only 4.4% to 26% in patients in the control group (40659,40679,40686,40691,40719,40728,40800,92985,96451,96452). The number needed to treat to achieve at least a 30% or 50% reduction in pain intensity is 10 and 12, respectively; the number needed to treat to achieve an additional beneficial outcome over placebo at 8 weeks and 12 weeks is 9 and 7, respectively (40800,96451). The pain reduction with this patch has an onset of a few days after treatment and the effect lasts for about 5 months (92986). However, some evidence shows that the reduction in pain is only significant for patients who have had postherpetic neuralgia for at least 6 months (40686). Additionally, the reduction in pain and duration of response appears to be greatest for patients with lower pain scores and low sensitivity to light touch at baseline, as well as patients not using concomitant systemic neuropathic pain medications, whereas patients with high pain scores, high sensitivity to touch, or those using systemic neuropathic pain medications experience the smallest and least sustained reduction in pain (40728,96458). Also, other evidence suggests that this patch may be less effective at relieving postherpetic neuralgia when compared with 5% lidocaine-medicated plaster (40688).

POSSIBLY EFFECTIVE

• Back pain. Topical capsicum or capsaicin seems to be beneficial for reducing back pain. Details: A meta-analysis of generally low-quality clinical research, as well as individual studies, show that applying a capsicum-containing plaster providing 11 mg of capsaicin per plaster or 22 mcg of capsaicin per square centimeter of plaster to the back once daily in the morning for 4-8 hours reduces low back pain when compared with placebo (15259,15260,15261). Applying capsaicin 0.05% (Finalgon CPD Warmecreme) three times daily for 21 days seems to cause a 58% reduction in low back pain when compared with placebo (17701). Also, in a mixed group of patients with acute back or neck pain, a large clinical trial shows that four topical applications with a gel containing capsaicin 0.075% with diclofenac 2% every 12 hours modestly reduces pain on motion when compared with diclofenac alone or placebo. The number of patients with at least a 50% reduction in pain from baseline was modestly higher. Capsaicin 0.075% was similarly effective alone and when combined with diclofenac 2% (105202). However, only about half of the patients in this study had back pain.
• Cluster headache. Intranasal capsaicin seems to be beneficial for preventing cluster headaches. Its effect in the treatment of cluster headache is unclear. Details: Some clinical research shows that using the capsicum constituent capsaicin intranasally reduces the frequency of episodic or chronic cluster headache attacks (14323,14351,14352,14358). Capsaicin suspensions of 0.1 mL of a 10 mM suspension, providing 300 mcg/day of capsaicin, has been applied to the ipsilateral nostril. Applications are continued once daily until a burning sensation is no longer experienced (14351,14358). Intranasal application of capsaicin 0.025% (Zostrix, Rodlen Laboratories) might also decrease symptom severity during an acute cluster headache attack. Clinical research shows that daily treatment for 7 days decreases symptom severity over the following week (14353). Ipsilateral, or same side, nostril application of capsaicin appears to be more effective than contralateral application (14351). Due to severe pain associated with intranasal capsaicin administration, pretreatment with intranasal local anesthetic is usually used.
• Nonallergic rhinitis. Intranasal capsaicin in a dose of at least 0.1 mM seems to improve symptoms of nonallergic rhinitis. It is unclear if lower doses of capsaicin are beneficial. Details: Clinical research shows that repeated intranasal in-clinic treatments with capsaicin, the active capsicum constituent, or with capsicum oleoresin, over a period of one to three days, can significantly decrease symptoms of non-allergic, non-infectious perennial rhinitis symptoms (14328,14357,15016,40595,105204,105205). A decrease of symptoms has been observed for up to 6-9 months following these treatments (14328,14357). The following doses have been used: capsaicin 0.15 mg per dose for up to 7 doses over a 14-day period (14328), capsaicin 0.0033 mol once weekly for 5 weeks (14357), capsaicin 15 mcg/0.1 mL applied three times daily for 3 days (15016), and capsaicin 1-4 mcg per puff, applied 3 times in each nostril daily for 3 days (40595). Due to severe pain associated with intranasal capsaicin administration, pretreatment with intranasal local anesthetic is usually used. Personal use of an intranasal spray with a lower dose of capsaicin might also be effective. Clinical research shows that two 0.4 mL puffs with an intranasal spray in each nostril daily for 4 weeks providing capsaicin 0.01 mM, but not 0.001 mM, is more effective than placebo for reducing symptoms of idiopathic rhinitis. This benefit is maintained for an additional 8 weeks. This protocol was at least as effective as receiving five repeated hourly intranasal spray treatments in hospital with capsaicin 0.1 mM (105204).
• Osteoarthritis. The American College of Rheumatology (ACR) conditionally recommends topical capsaicin for knee osteoarthritis, but not for hip or hand osteoarthritis. Details: A meta-analysis of 4 preliminary clinical trials shows that using topical capsaicin 0.025% four times daily has modest benefit for osteoarthritis when compared with placebo. Using capsaicin 0.0125% doesn't seem to be effective (102408). The American College of Rheumatology (ACR) conditionally recommends topical capsaicin for knee osteoarthritis. However, it does not recommend its use for hip osteoarthritis due to the depth of the joint beneath the skin surface, nor for hand osteoarthritis, due to the risk for contamination of the eye (102114).
• Pain (acute). Topical capsicum seems to be beneficial for reducing acute pain due to trauma. Details: Clinical research in patients with trauma-related acute pain shows that topical application with a gel (Sanli Gel) containing capsaicin 0.05% three times daily for 3 days reduces pain by at least 50% in 87% of patients, compared with 63% of those using a piroxicam gel 0.5% (Felden). There was also a significantly greater number of patients with a final pain score of 4 or less. In the capsaicin group, only 12% of patients did not achieve either of these endpoints, compared with 31% in the group receiving piroxicam (105197).
• Postoperative nausea and vomiting (PONV). Applying topical capsicum to acupoints seems to be beneficial for preventing PONV. Details: Clinical research shows that applying a capsicum-containing plaster to acupoints on the hand and forearm 30 minutes prior to anesthesia and leaving in place for 6-8 hours daily for up to 3 days after surgery reduces the incidence of PONV by about 29% to 36% when compared to control (40405,40483,40610). Plasters used in these studies included Sinsin PAS (Sinsin Pharm Co.), which is standardized to contain capsicum 345.8 mg and capsicum tincture 34.58 mg per sheet (40405,40610); and Johnson's Perforated Capsicum Plaster (Johnson & Johnson Ltd.), which is standardized to contain capsicum oleoresin 1% w/w (40483).
• Postoperative pain. Applying topical capsicum-containing plaster to acupoints seems to be beneficial for reducing postoperative pain. It is unclear if a capsicum patch or capsaicin instillation prior to wound closure is beneficial for reducing postoperative pain. Details: Some clinical research shows that applying a capsicum-containing plaster to acupoints on the hands or near the knees of adults or children 30 minutes prior to anesthesia, and leaving in place for 6-8 hours daily for up to 3 days after surgery, reduces the amount of rescue analgesics needed by 29% to 39% within the first 24 hours and by 16% to 19% within the first 48 hours when compared to control (40405,40483,40520,40524,40610). The capsicum-containing plaster used in these studies (Sinsin PAS, Sinsin Pharm Co.) is standardized to contain capsicum 345.8 mg and capsicum tincture 34.58 mg per sheet (40520,40610). Other preliminary clinical research shows that applying a single patch containing the capsicum constituent capsaicin 8% (Qutenza, NeurogesX Inc.) for 30-60 minutes leads to an improvement in overall health status and an average 22% reduction in pain that lasts up to 12 weeks in patients with postoperative and posttraumatic neuropathic pain. Patches were applied to various parts of the body, including the legs, torso, feet, hands, arms, head, and neck, and the reduction in pain continued with the use of a second and third patch application. The validity of these findings is limited by the lack of a control group (96452). Other clinical evidence suggests that instilling capsaicin 15 mg during surgery immediately prior to wound closure reduces the need for pain medication for up to 2 weeks postoperatively when compared with placebo (40741).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). It is unclear if intranasal capsaicin is beneficial for preventing allergic rhinitis symptoms. Details: Preliminary clinical research shows that intranasal treatment with cotton wads soaked in the active capsicum constituent capsaicin 30 mcM, applied for 15 minutes and repeated over two days, reduces the severity of experimentally-induced allergic rhinitis. The severity of symptoms seems to be reduced for up to 2 months after treatment (14324). However, contradictory research shows that patients with allergic rhinitis caused by house dust mites do not have significantly improved symptoms after using a capsaicin solution providing 0.15 mg/dose for up to 7 doses over a 14-day period when compared with placebo (14360).
• Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease). Although there is interest in using oral capsicum for ALS, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• Athletic performance. It is unclear if oral capsaicin is beneficial for improving athletic performance; the available research is limited to small, conflicting studies. Details: Several small clinical studies in physically active young adults show that taking capsaicin might improve some measures of athletic performance, but results are mixed overall (99409,99410,102276,105191,105198,105200). A meta-analysis of these and several other small clinical studies shows that taking the capsicum constituents capsaicin or capsiate 45 minutes before exercise improves measures of muscular endurance but does not improve aerobic endurance when compared with placebo. Doses of the capsicum constituents ranged from 1.2-24 mg, with most studies assessing a single 12 mg dose (111515). The included studies have a number of methodological problems that limit the validity of the findings, such as a small sample size, short study duration, and insufficient blinding. Also, most of the study participants were male. Other small clinical studies not included in the meta-analysis also show conflicting results. One small clinical study in untrained young adults undergoing resistance training shows that taking capsiate, a capsaicin analog, 6 mg orally twice daily for 6 weeks improves upper body, but not lower body, weightlifting performance when compared with placebo (109024). However, another small clinical trial in experienced male athletes shows that taking cayenne (GNC Nature's Fingerprint Cayenne Herbal Supplement) 3 grams, providing capsaicin 25.8 mg, daily for 7 days does not improve sprint time, rate of perceived exertion, or muscle soreness over three days when compared with placebo (105206). Capsicum has also been evaluated in combination with other ingredients. One small clinical study in untrained males shows that taking a supplement containing capsicum extract 66.7 mg, caffeine 400 mg, black pepper extract 10 mg, and niacin 40 mg prior to exercising does not improve strength, time to exhaustion, or maximal oxygen consumption when compared with placebo (37873).
• Burning mouth syndrome. It is unclear if applying topical capsaicin in the mouth is beneficial for burning mouth syndrome. Details: Preliminary clinical studies show that using 15 mL of a mouth rinse containing the active capsicum constituent capsaicin 0.02% for 30 seconds daily for 7-21 days modestly decreases burning discomfort when compared to baseline in patients with burning mouth syndrome (92991,105195). Other preliminary clinical research shows that applying 0.5 mL of a gel containing capsaicin 0.01% or 0.025% to the tongue three times daily for 14 days modestly reduces pain when compared to baseline in patients with burning mouth syndrome. The gel is spread with a cotton swab, and no food or drink is consumed for 30 minutes after application (96456). The validity of these findings is limited by the lack of a control group, the small number of patients, and occasionally unclear statistical comparisons.
• Cancer. It is unclear if eating more chili is beneficial for preventing mortality due to cancer. Details: Population research has found that consuming chili more than four times weekly is not associated with a reduced odds of cancer mortality (105208). Also, other population research has found that any consumption of hot red chili peppers is not associated with a reduced odds of mortality related to cancer (105210).
• Cannabinoid hyperemesis syndrome (CHS). Preliminary clinical research suggests that topical capsaicin might be beneficial for reducing symptoms of CHS. Details: One small clinical study in adults presenting to an emergency department (ED) with CHS shows that applying 5 grams of a cream containing capsaicin 0.1% to the abdomen modestly reduces nausea severity at 60 minutes, but not 30 minutes, when compared with a placebo cream. Nausea was completely resolved in 29% of patients, compared with 0% of those using the placebo cream. However, there was no difference in vomiting at 30 or 120 minutes (105193). This study may not have been adequately powered to detect a difference in some of these outcomes. A meta-analysis of two small, low-quality studies involving the topical use of capsaicin on the abdomen, chest, and possibly back, shows that the mean time to resolution of symptoms was 326 minutes and the mean length of stay in the emergency department was 379 minutes. However, it is unclear how these times compare to the use of placebo or standard antiemetics. This study also conducted a systematic review of the available literature, which indicates that the creams most commonly used in research provide 0.025% to 0.1% capsaicin (105201). Two low-quality, retrospective reviews also suggest that capsaicin cream may be beneficial for CHS. A retrospective review of patients in the ED with CHS has found that applying capsaicin cream 0.025% is associated with a 39% shorter time to discharge when compared with control. Patients treated with capsaicin also required fewer additional rescue treatments when compared with control (109021). Another retrospective review of patients in the ED with CHS also suggests that capsaicin cream 0.025% modestly reduces abdominal pain when compared with baseline. However, 47% and 28% of patients, respectively, received additional antiemetics or an opioid after the use of the cream (105345).
• Cardiovascular disease (CVD). It is unclear if eating more chili is beneficial for preventing mortality due to CVD. Details: Population research has found that consuming chili more than four times weekly is associated with a 34% reduced odds of CVD mortality when compared with never or rarely consuming chili, as well as 44% and 61% reduced odds of ischemic heart disease and cerebrovascular death, respectively (105208). Other population research has found that consumption of hot red chili peppers is not associated with a reduced odds of mortality related to CVD when compared with not eating hot red chili peppers (105210).
• Diabetes. It is unclear if oral capsaicin is beneficial for gestational diabetes. Details: Preliminary clinical research shows that taking chili powder containing capsaicin 5 mg daily for 4 weeks modestly reduces total cholesterol levels and reduces postprandial blood glucose levels by an average of 36 mg/dL and postprandial insulin levels by an average of 14 IU/L in patients with gestational diabetes. Compared to a placebo group, these changes are significant. However, capsaicin intake does not alter fasting plasma glucose or insulin levels (96457).
• Dry skin. It is unclear if oral capsicum is beneficial for dry skin. Details: Preliminary clinical research in adult females with low skin moisture shows that taking paprika oil extract 400 mg, standardized to include 9 mg of xanthophyll, orally daily for 4 weeks improves skin moisture and viscoelasticity scores, but not the number of wrinkles, when compared with control (109026).
• Dyslipidemia. It is unclear if oral capsicum is beneficial for reducing lipid levels. Details: A meta-analysis of three or four mainly small clinical trials in healthy adults shows that taking capsicum does not improve levels of triglycerides, total cholesterol, or high-density lipoprotein (HDL) cholesterol when compared with no treatment or placebo. However, there was a small to moderate effect on levels of low-density lipoprotein (LDL) cholesterol. Freshly chopped chili or fermented red pepper were studied for 4 and 12 weeks, respectively (105194). It is unclear if capsicum can lower lipid levels in patients with dyslipidemia or hyperlipidemia.
• Dyspepsia. It is unclear if oral capsicum is beneficial for dyspepsia. Details: Preliminary clinical research shows that taking red pepper powder 2.5 grams daily in three divided doses for 5 weeks reduces symptoms of functional dyspepsia when compared with placebo. However, in some patients, there seems to be a worsening of symptoms prior to any improvement (12410).
• Fibromyalgia. It is unclear if oral capsicum is beneficial for fibromyalgia. Details: Preliminary clinical research shows that applying cream containing the active capsicum constituent capsaicin 0.025% four times daily to tender points for 4 weeks reduces localized tenderness in patients with fibromyalgia (7038). Other preliminary clinical research shows that applying capsaicin 0.075% cream (Sensedol) three times daily to tender points for 6 weeks in addition to standard therapy increases the pain threshold when compared with standard therapy in patients with severe fibromyalgia (92979). However, capsaicin does not appear to reduce overall pain or improve physical function in patients with fibromyalgia (7038,92979). Also, the long-term effects of capsaicin on fibromyalgia-related pain are unclear.
• Gastroesophageal reflux disease (GERD). Although there is interest in using oral capsicum for GERD, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• HIV/AIDS-related peripheral neuropathy. It is unclear if topical capsaicin is beneficial for this condition. Details: There is conflicting evidence regarding the effects of Qutenza (NeurogesX Inc.), which contains the active constituent of capsicum, capsaicin 8%. Although some research shows it reduces pain in patients with HIV and peripheral neuropathy (22395), other research shows no significant benefit (40746). A meta-analysis of results from both of these studies shows that applying a single capsaicin 8% patch for 30-90 minutes reduces pain intensity by at least 30% in about 30% more patients when compared to control (40800). Additional meta-analyses of the results from these two studies suggests that pain reduction with capsaicin begins a few days after treatment and lasts for about 5 months, with a number needed to treat of 11 to achieve at least a 30% reduction in pain intensity (92986,96451). Reduction in pain and duration of response appears to be greatest for females with lower pain scores at baseline, whereas males with high pain scores at baseline experience the smallest and least sustained reduction in pain (96458). Some research has also evaluated topical capsaicin 0.075%. One small clinical study shows that applying this cream does not relieve symptoms of HIV-associated peripheral neuropathy when compared with placebo (3891).
• Hypertension. It is unclear if oral capsicum is beneficial for lowering blood pressure. Details: Two meta-analyses of small clinical trials show that taking capsicum as freshly chopped chili, fermented red pepper, red pepper capsules, or capsinoid capsules orally daily for 4-12 weeks does not reduce systolic or diastolic blood pressure when compared with control. However, most subjects included in these clinical trials did not have hypertension (105194,109025).
• Intermetatarsal neuroma. It is unclear if injecting capsaicin into the third intermetatarsal space is beneficial for intermetatarsal neuroma. Details: Clinical research in adults with intermetatarsal neuroma shows that a single injection of capsaicin 0.1 mg into the third intermetatarsal space 5 minutes after administration of 2 mL of lidocaine 2% with epinephrine leads to a modest reduction in pain at weeks 1 and 4, but not weeks 2 and 3, when compared with placebo. Capsaicin also reduces the extent to which pain interferes with walking and mood, but not with work, sleep, relationships, or general activity (96454).
• Irritable bowel syndrome (IBS). It is unclear if oral capsicum is beneficial for IBS. Details: Preliminary clinical research shows that taking ground guajillo chili 1 gram, containing capsaicin 0.112%, with each meal for 7 days does not reduce symptoms of IBS (12403). A small clinical study shows that taking chili (Nguan Soon Co., Ltd.) 2.1 grams, providing 2.5 mg capsaicin, daily before meals for 6 weeks does not improve abdominal burning, fecal urgency, or abdominal pain or bloating after a spicy meal. However, there was a modest reduction in abdominal burning after a spicy meal (105207). This study may not have been adequately powered to detect a difference in some of these outcomes.
• Laryngitis. Although there is interest in gargling with capsicum for laryngitis, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• Motion sickness. Although there is interest in oral capsicum for motion sickness, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• Myofascial pain syndrome. It is unclear if topical capsaicin is beneficial for myofascial pain syndrome. Details: Preliminary clinical research shows that applying a specific capsaicin cream (Dipental Cream, Dalim BioTech) containing capsaicin 0.25 mg/gram along with a ketoprofen 30 mg patch (KetotopVRPlaster, Pacific Pharma) to the trapezius does not reduce pain when compared with a ketoprofen patch alone in patients with myofascial pain (92983).
• Neck pain. It is unclear if topical capsaicin is beneficial for neck pain. Details: In a group of patients with acute back or neck pain, a large clinical trial shows that four topical applications with a gel containing capsaicin 0.075% with diclofenac 2% every 12 hours modestly reduces pain on motion when compared with diclofenac alone or placebo. The number of patients with at least a 50% reduction in pain from baseline was modestly higher. Capsaicin 0.075% was similarly effective alone or when combined with diclofenac 2% (105202). However, only about half of the patients in this study had neck pain.
• Neuropathic pain. It is unclear if topical capsicum is beneficial for neuropathic pain. Details: A very small study in adults with neuropathic pain secondary to spinal cord injury shows that applying a patch containing the capsicum constituent capsaicin 8% for 60 minutes daily to the affected area for 12 weeks reduces pain at weeks 2 and 4 and improves mobility, but not quality of life, for up to 12 weeks when compared with placebo (111517). The validity of these findings is limited by insufficient blinding and the small sample size.
• Obesity. It is unclear if oral capsicum is beneficial for obesity. Details: A meta-analysis of 3-5 small clinical trials shows that taking capsicum does not reduce body weight, body fat, or body mass index (BMI) in individuals with a BMI of at least 25 kg/m2 when compared with placebo or no treatment. Freshly chopped chili, fermented red pepper, or capsicum constituents were studied for 4-12 weeks (105194). In one clinical trial included in the analysis, taking capsinoids 3 mg twice daily 30 minutes prior to eating for 12 weeks reduced abdominal fat by about 1%, but did not significantly reduce body weight, when compared with placebo (40599). In overweight individuals, one small clinical trial shows that taking a specific chili extract 200 mg, formulated with fenugreek dietary fiber for sustained release (Capsifen, Akay Natural Ingredients), providing capsaicinoids 4 mg daily for 28 days reduces body weight and BMI by about 2% when compared with placebo. There was no effect on blood pressure (105196). Capsicum has also been evaluated in combination with other ingredients, with some evidence of benefit. One study evaluated a combination product (Prograde Metabolism) containing capsicum extract (Capsimax, OmniActive Health Technologies), raspberry ketone (Razberi K, Integrity Nutraceuticals), caffeine, garlic root extract, ginger root extract, bitter orange fruit (Advantra Z, Nutratech Inc), L-theanine, and black pepper fruit extract (Biperine, Sabinsa Corporation) twice daily for 8 weeks (40802).
• Overall mortality. Eating chili may be beneficial for preventing mortality. It is unclear if taking capsicum supplements is beneficial for preventing overall mortality. Details: Population research has found that consuming chili is associated with a reduced risk of overall mortality. In one study, eating chili more than four times weekly was associated with a 23% reduced odds of overall mortality when compared with never or rarely consuming chili (105208). Other population research has found that any consumption of hot red chili peppers is associated with a 13% reduced odds of mortality when compared with not eating these peppers (105210). Also, eating spicy foods at least once each week, consisting mainly of fresh chili pepper, dried chili pepper, chili sauce, or chili oil, was associated with at least a 10% reduced risk of death when compared with eating these foods less than once a week (105211).
• Peptic ulcers. It is unclear if oral capsicum is beneficial for peptic ulcers. Details: Population research has found that eating capsicum fruit (chili) an average of 24 times per month is associated with a reduced likelihood of having an ulcer when compared with eating chili an average of 8 times per month. This applies to chili in the form of chili powder, chili sauce, curry powder, and other chili-containing foods (12053). However, clinical research shows that consuming chili peppers 1 gram three times daily for 4 weeks does not improve duodenal ulcer healing when compared to control (40828).
• Peripheral neuropathy. Preliminary clinical research suggests that topical capsaicin might be beneficial for reducing peripheral neuropathy pain. Details: Preliminary clinical research shows that applying patches containing the capsicum constituent capsaicin 8% (Qutenza, NeurogesX Inc.) reduces pain in people with non-diabetic peripheral neuropathy (96452,111516). Up to four patches, applied to different painful areas, are used at one time and are left in place for 30 minutes on the feet, or 60 minutes on other parts of the body such as the legs, torso, hands, arms, head, or neck (96452). After an interval of at least 90 days, treatment can be repeated, with new patches applied for 30-60 minutes (99407). There is an average 27% reduction in pain when compared to baseline, lasting up to 12 weeks (96452). Another similar study reported a decrease of 1 point, on a 10-point pain scale, in the typical daily pain intensity (99407). The validity of these findings is limited by methodological problems, including the lack of control groups. Further research shows that using a single application of up to four capsaicin 8% patches for 30-60 minutes, or taking pregabalin orally, 150-600 mg in 2-3 divided doses daily for 8 weeks, reduces the intensity and area of dynamic mechanical allodynia (DMA, pain evoked by light brushing of the skin) in people with non-diabetic peripheral neuropathy. Complete resolution of DMA occurred in 24% of people using the patches, and 12% of those taking pregabalin (99408). The validity of these findings is limited by methodological problems, including a lack of blinding.
• Prurigo nodularis. It is unclear if topical capsaicin is beneficial for prurigo nodularis. Details: Preliminary clinical research shows that applying a cream containing the active capsicum constituent, capsaicin 0.025% to 0.3%, 4-6 times daily improves burning sensations, erythema, pruritus, and healing of skin lesions over a period of 2 weeks to 33 months when compared to baseline. Symptoms may return after discontinuation of therapy (10650).
• Sinonasal polyposis. It is unclear if intranasal capsaicin is beneficial for sinonasal polyposis. Details: Preliminary clinical research in patients with severe sinonasal polyposis shows that intranasal application of 0.5 mL of a 30 mmol/L capsaicin solution to each nostril for 3 days, followed by 0.5 mL of a 100 mmol/L capsaicin solution for 2 days, can cause significant subjective improvement in symptoms as well as objective improvement in nose/sinus air volume and endoscopy scores; however, capsaicin does not seem to significantly affect eosinophil cationic protein levels (14359).
• Swallowing dysfunction. Preliminary research shows that oral capsaicin might be beneficial for improving swallowing ability. Details: Preliminary clinical research shows that elderly patients at risk for aspiration pneumonia due to swallowing dysfunction have improved swallowing reflexes after dissolving a lozenge containing capsaicin 1.5 mcg in the mouth before each meal when compared with using a placebo lozenge (13100). Preliminary clinical research also shows that capsaicin may be beneficial in patients with swallowing dysfunction due to stroke (102278,105192). One study shows that taking 1 mL of nectar containing capsaicin 150 mcM/L with each meal daily for 3 weeks, in addition to thermal tactile stimulation, improves eating and swallowing when compared with using thermal tactile stimulation and placebo nectar (102278). Another study shows that 20 minutes of stimulation with an ice swab containing capsaicin 0.15 mM before lunch and dinner daily for three weeks modestly improves the ability to swallow water when compared with ice stimulation alone. After treatment, approximately 70% of those using the capsaicin ice were able to drink the water without choking, compared with only 33% in those using ice alone (105192). Capsaicin solution has also been administered by nebulizer. A clinical study in patients with swallowing dysfunction secondary to hemorrhagic stroke shows that inhaling capsaicin solution twice daily for one week reduces the incidence of post-swallow residue and pulmonary infection and increases number of coughs in response to capsaicin compared with placebo. However, treatment with nebulized capsaicin does not reduce the number of patients with swallow or cough reflexes compared with control (111518). More evidence is needed to rate capsicum for these uses.

(Read more about CAPSICUM)

There is insufficient reliable information available about the effectiveness of lousewort.

(Read more about LOUSEWORT)

EFFECTIVE

• Bowel preparation. Various magnesium salts are used for cleansing the bowel prior to procedures such as colonoscopy. Details: Various magnesium salts, including citrate, hydroxide, oxide, and sulfate, are ingredients in bowel preparation products available over-the-counter or by prescription only.
• Constipation. Magnesium salts are effective when used short-term orally to treat constipation and chronic idiopathic constipation (CIC). Details: Magnesium citrate, hydroxide, oxide, and sulfate salts are commonly used as laxatives. Magnesium citrate 11.3-17.45 grams has been used; magnesium hydroxide 2.4-4.8 grams, as 30-60 mL of milk of magnesia, has also been used (113483,113484). Magnesium sulfate, also known as Epsom salt, which seems to have the most potent effect, has been used as 10-30 grams (6430,113485). Magnesium salts should only be used for occasional treatment of constipation, and doses should be taken with a full 8-ounce glass of water. Magnesium oxide seems to be beneficial in adults with CIC when taken short-term. Clinical guidelines published by the American Gastroenterology Association and American College of Gastroenterology in 2023 give a conditional recommendation suggesting the use of magnesium oxide over managing CIC without magnesium oxide based on low-quality studies conducted over 4 weeks. The recommended starting dose is 400-500 mg daily with dose titration per symptom response and side effects (112859). A small clinical study in patients with CIC who are not taking chronic medications shows that taking magnesium oxide 1.5 grams in three divided doses daily for 28 days increases spontaneous bowel movements when compared with placebo (104397). It is unknown if magnesium is beneficial for CIC when used long-term.
• Dyspepsia. Magnesium salts are effective when used orally as antacids. Details: Magnesium carbonate, hydroxide, oxide, or trisilicate salts are used orally as antacids to reduce symptoms of gastric hyperacidity or gastroesophageal reflux. Magnesium hydroxide has the fastest onset of action. The onset for magnesium carbonate is slower due to its crystal structure. Magnesium trisilicate has the slowest onset and longest duration of action due to poor solubility (6844). Doses used include magnesium hydroxide 400-1200 mg (5-15 mL of milk of magnesia) up to four times daily, or magnesium oxide 800 mg daily (15).
• Eclampsia. Magnesium sulfate is considered the drug of choice for control of seizures. Details: Intravenous (IV) and/or intramuscular (IM) magnesium sulfate is considered the agent of choice for seizure prophylaxis during eclampsia by the American College of Obstetricians and Gynecologists (ACOG) (15,12591,12592,61012,61184). Typical doses include 4-6 grams of magnesium sulfate by IV infusion in 250 mL of dextrose 5% or normal saline solution, followed by 4-5 grams of magnesium sulfate IM every 4 hours, or 1-3 grams per hour by continuous IV infusion. Doses should be adjusted according to serum levels and urinary excretion, and should not exceed 30-40 grams of magnesium sulfate daily (15,12591). Meta-analyses of clinical research show that treatment with IV or IM magnesium reduces the risk of seizure recurrence by 33% to 69% when compared with phenytoin, and by 47% to 60% when compared with diazepam (19960,60818,60954,60964,61105). One preliminary clinical study shows that lower doses of IV magnesium sulfate (9 grams loading dose and maintenance of 2.5 grams every 4 hours for 24 hours) are as effective as higher doses (14 grams loading dose and maintenance of 5 grams every 4 hours for 24 hours) for reducing the recurrence of eclamptic seizures (89383). It is generally recommended that treatment be continued for at least 24 hours after the last seizure (15). Oral magnesium has not been evaluated for eclampsia.
• Hypomagnesemia. Hypomagnesemia can be effectively treated with oral or parenteral magnesium. Details: Taking magnesium orally or parenterally is helpful for treating and preventing hypomagnesemia associated with alcoholism, cirrhosis of the liver, congestive heart failure (CHF), severe or prolonged diarrhea or vomiting, kidney dysfunction, inflammatory bowel disease (IBD), pancreatitis, malabsorption syndromes, and other conditions (6280,6281,8088,8089). The dose and salt of magnesium for oral replacement therapy should be chosen carefully to avoid causing diarrhea. The gluconate and chloride salts cause less diarrhea, while the oxide salt is more likely to cause diarrhea and should be avoided. Magnesium chloride should also be avoided due to poor solubility which decreases absorption (6430,8099,10664). Orally, magnesium sulfate 3 grams every 6 hours for four doses has been used for hypomagnesemia (15). Parenteral magnesium doses must be individualized according to serum magnesium levels, but a typical starting dose for mild deficiency is 1 gram of magnesium sulfate intramuscularly (IM) every 6 hours for 4 doses (15). For more severe deficiency, 5 grams of magnesium sulfate may be given as an intravenous (IV) infusion in 1 liter of dextrose 5% or normal saline solution over 3 hours (15).
• Pre-eclampsia. Magnesium sulfate is considered the drug of choice for seizure prophylaxis in patients with pre-eclampsia. Details: Intravenous (IV) and/or intramuscular (IM) magnesium sulfate is considered the agent of choice for seizure prophylaxis during pre-eclampsia by the American College of Obstetricians and Gynecologists (ACOG) (12591,12592,61012,61184). Some meta-analyses show that IV administration of magnesium sulfate reduces the risk of eclampsia when compared with placebo, phenytoin, or diazepam in patients with pre-eclampsia (19960,60818,60960,60979). A typical initial dose is 4-5 grams of magnesium sulfate by IV infusion in 250 mL of dextrose 5% or normal saline solution, followed by 4-5 grams of magnesium sulfate IM every 4 hours, or 1-3 grams of magnesium sulfate per hour by continuous IV infusion. Doses should be adjusted according to serum levels and urinary excretion, and should not exceed 30-40 grams of magnesium sulfate daily (15,12591). The optimal duration of prophylaxis has not been determined. A meta-analysis suggests that using a shorter duration of 12 hours or less is not associated with an increase in risk of eclamptic seizures when compared with regimens of 24 hours or longer (108732). However, studies are likely underpowered due to the low incidence of eclampsia. Oral magnesium has been evaluated for the prevention of pre-eclampsia in healthy adults, but taking magnesium citrate 300 mg daily, starting at 12-20 weeks' gestation and continuing until delivery, does not reduce the incidence of pre-eclampsia when compared with placebo (103724).

LIKELY EFFECTIVE

• Cerebral palsy. Most evidence shows that antenatal magnesium reduces the risk of cerebral palsy in preterm infants, although there are some inconsistent results. Details: Most clinical studies and meta-analyses show that antenatal magnesium sulfate reduces the risk of cerebral palsy by about 32% and the risk of motor dysfunction by about 45% in preterm infants (60915,60927,60931,61001,97485,103734,103754,114675,114681). The lowest effective dose of magnesium sulfate seems to be 4 grams intravenously, with or without a maintenance dose of 1 gram/hour until birth or for 24 hours. In obese females, a higher dose, based on body weight, may be needed (97485,97495,103734,103754). However, some studies have inconsistent results (8093,19998,98293,98295,112784). Giving females at risk of imminent preterm birth (prior to 32 weeks), intravenous magnesium sulfate 4.5 grams over 20 minutes followed by 1 gram per hour until birth or for 24 hours, in addition to a standard treatment protocol, does not reduce the incidence of cerebral palsy (112784). Oral magnesium has not been evaluated for this purpose.
• Seizures. Intravenous magnesium sulfate is used for treating seizures of various etiologies. Details: Intravenous magnesium sulfate may be useful for controlling seizures associated with epilepsy, glomerulonephritis, hypothyroidism, and acute nephritis in children (15). Oral magnesium has not been evaluated for this purpose.
• Torsades de pointes. Intravenous magnesium sulfate is the first-line treatment for torsades de pointes after measures to correct precipitating factors have been unsuccessful. Details: Intravenous magnesium sulfate has been used successfully to treat the life-threatening ventricular tachycardia, torsades de pointes (15,6844). The Advanced Cardiac Life Support (ACLS) guidelines of the American Heart Association recommend a dose of 1 to 2 grams diluted in 50-100 mL Dextrose 5% solution given IV over 5-60 minutes, followed by a continuous IV infusion of 0.5-1 gram/hour.

POSSIBLY EFFECTIVE

• Arrhythmia. Magnesium sulfate is effective for the specific type of ventricular tachycardia known as torsades de pointes, and seems to be helpful for treating other types of arrhythmias. Evidence for the role of oral or intravenous magnesium in preventing postoperative arrhythmias is conflicting. Details: Administering magnesium intravenously or orally may be helpful for treating atrial and ventricular tachycardia and fibrillation, and supraventricular tachycardia (9497,13352,13354,13355,13356,60804,60829,60877,61113,111696). Arrhythmias associated with congestive heart failure have been treated with magnesium sulfate 8 grams infused over 12 hours (9497). For rate control in atrial fibrillation, magnesium sulfate 2.5 grams IV over 20 minutes, followed by 2.5 grams IV over 2 hours has been used (13356). For paroxysmal supraventricular tachycardia, single doses of 1-4 grams of magnesium chloride have been used (13352). For atrial tachycardia, 2 grams of magnesium sulfate in 10 mL of dextrose 5% solution has been given IV over 1-10 minutes, followed by 5-10 grams of magnesium sulfate in 250-500 mL dextrose 5% solution as an IV infusion over 5 hours (13354,13355). Research on the effects of intravenous magnesium for preventing arrhythmias after cardiac surgery is conflicting. Some meta-analyses show that intravenous magnesium reduces the risk of atrial fibrillation, ventricular arrhythmias, or supraventricular arrhythmias following cardiac surgery by 23% to 48% when compared with placebo (60814,60826,60828,60838,61008,61033,61181,97487,97490). Doses of magnesium sulfate used include 30 mg/kg in 500 mL normal saline (97490), or 80-100 mg/kg added to the cardioplegia solution (97487). Also, one small study in adults after CABG surgery suggests that taking magnesium hydroxide 1600 mg orally reduces arrhythmia as effectively as receiving magnesium sulfate 2000 mg intravenously (99315). However, other meta-analyses that only include higher-quality trials show that magnesium supplementation does not reduce the risk of ventricular or supraventricular arrhythmias following cardiac surgery (61010,61024,61031,105081). A meta-analysis of clinical trials of intravenous magnesium for prevention of new-onset atrial fibrillation after non-cardiac surgeries shows that it does not reduce the incidence significantly when compared with placebo (112778). However, there was a high risk of bias in the analysis, and variability in types of surgery, and the salt and dose of magnesium used.
• Asthma. Parenteral magnesium sulfate can help to reverse severe acute asthma attacks and reduce the need for hospital admission. It is unclear if nebulized magnesium is beneficial for acute asthma attacks. However, oral magnesium does not seem to be beneficial. Details: Overall, a single dose of intravenous magnesium seems to improve pulmonary function in acute asthma exacerbation and reduce the risk of hospitalization, particularly in patients with severe asthma, and those who have failed initial treatment with nebulized albuterol and intravenous corticosteroids (60888,90023,96483,104398,107365). The typical dose used for adults is 2 grams of magnesium sulfate infused over 20 minutes (15). For children, 25-75 mg/kg, to a maximum of 2 grams, infused over 20-30 minutes has been used (15,96483,107365). However, a post-hoc analysis of one large clinical trial (104400) designed to assess nebulized magnesium in children with acute asthma has found that adding IV magnesium to nebulized magnesium is associated with greater odds of hospitalization when compared with no IV magnesium (105919). This post-hoc analysis did not differentiate between precautionary and necessary hospitalizations. Although some clinical research and a meta-analysis in patients with acute asthma exacerbation show that nebulized magnesium in combination with standard treatment improves airway function, respiratory rate, and clinical asthma severity when compared with standard treatment alone, it is unclear whether these findings are clinically relevant (90016,113466). Most evidence, including larger clinical trials and meta-analyses, has not shown benefit of adjunct nebulized magnesium for acute asthma in adults or children (60888,90002,96484,104400,105920,113466,114674). Oral magnesium also does not seem to be beneficial. A meta-analysis of small clinical trials in children and adults with asthma shows that taking magnesium supplements orally does not improve lung function or reduce bronchodilator use when compared with control (104404).
• Colorectal cancer. Increasing dietary magnesium intake seems to lower the risk of colon cancer but not rectal cancer. Details: Epidemiological research shows that increased dietary magnesium intake is associated with a reduced risk of colon cancer, but the risk of rectal cancer is not affected (89387,90017,90027,101355).
• Diabetes. Low dietary magnesium may increase the risk of developing type 2 diabetes, but evidence on the use of supplements for treating type 2 diabetes is conflicting. Details: Higher dietary magnesium intake is associated with lower fasting insulin concentrations and a reduced risk of developing type 2 diabetes in adults and obese children (13369,15548,96473,97486,98294,103736,105918,106920). In people with existing type 2 diabetes, hypomagnesemia is found in 25% to 38% of patients, especially in those with poorly controlled diabetes (1172). Population research in adults with type 2 diabetes also shows that a dietary magnesium intake of less than 250 mg daily is associated with a 56% higher risk of mortality. Preliminary subgroup analyses suggest that the risk of mortality is higher in those with glycated hemoglobin (HbA1C) levels above 7% (110051). A meta-analysis of small, heterogeneous clinical studies in adults with type 2 diabetes suggests that magnesium may modestly reduce HbA1C in patients with hypomagnesemia, but not in patients with normal magnesium levels, when compared with control (105075). Individual clinical studies using magnesium supplements in patients with type 2 diabetes or insulin resistance have shown mixed results. Some research suggests magnesium supplements can decrease fasting blood glucose and improve insulin sensitivity, as well as reduce the risk of developing diabetes in high-risk patients (10664,12582,13376,60854,99313,106920), but other research shows no effect (1171,1172,13379,13380,112780). Discrepancies in these findings might reflect differences in magnesium salts and doses used, or differences in baseline magnesium status in study subjects.
• Hypercholesterolemia. Magnesium may help improve lipid levels by a small amount in people with this condition. Details: There is some evidence that taking magnesium oxide 1 gram orally daily for 6 weeks can produce small decreases in low-density lipoprotein (LDL) and total cholesterol levels, and small increases in high-density lipoprotein (HDL) levels in patients with hypercholesterolemia. However, magnesium does not seem to improve lipoprotein (a) levels (1193). Magnesium may also lower triglycerides in people with hypertriglyceridemia (97494).
• Metabolic syndrome. Low dietary and serum levels of magnesium seem to be associated with the development of metabolic syndrome. Details: Higher magnesium intake from diet and supplements is associated with a 27% lower risk of developing metabolic syndrome in healthy females (13371) and a 31% lower risk in healthy young adults (14304). Additional epidemiological research suggests that people with low serum magnesium levels are 6-7 times more likely to have metabolic syndrome than people with normal magnesium levels (13372). In a population analysis of over 6000 individuals without metabolic syndrome at baseline, the risk of developing this condition over a 6-year follow-up period was reduced by 16% in the highest quintile of dietary magnesium intake (median intake 371 mg daily) when compared with the lowest quintile (median intake 203 mg daily). Some, but not all, research suggests that the hazard ratio for metabolic syndrome in relation to magnesium intake may be U-shaped, with higher risk at intakes below about 150 mg daily and above 600 mg daily (108963). A combination of magnesium 20 mEq daily and potassium 40 mEq daily (magnesium potassium citrate) taken orally for 16 weeks reverses metabolic side effects of chlorthalidone, such as increased fasting plasma glucose and hypokalemia, more effectively than potassium chloride 40 mEq daily alone (112932).
• Osteoporosis. Increased dietary and supplemental magnesium intake seems to increase bone mineral density and decrease bone loss in postmenopausal patients. Details: Preliminary clinical research shows that taking magnesium hydroxide orally, 300-1800 mg daily for 6 months, then 600 mg daily for 18 months, or magnesium citrate orally 1830 mg daily for 30 days, might reduce bone loss and bone turnover in postmenopausal patients with osteoporosis (9104,60928). Some epidemiological research also suggests that magnesium intake is related to increased bone mineral density (12501,12502,12503,12504,90014), although not all studies have found an association (12505,98286).
• Postoperative pain. Injectable magnesium has been used with promising results for reducing pain and the need for other analgesics postoperatively. Details: A meta-analysis of 25 clinical trials shows that intravenous (IV) magnesium sulfate, 5-50 mg/kg bolus followed by a continuous infusion of 6 mg/kg or 500 mg hourly during surgery, seems to reduce the 24-hour postoperative use of IV morphine by 24% when compared with placebo (19968). Adding IV magnesium sulfate 3.7-5.5 grams to patient-controlled analgesia for 24 hours after surgery has also been used (19968). Additionally, meta-analyses support that adjunctive IV or intrathecal administration of magnesium reduces post-operative pain scores, improves pain relief and sensory nerve block, and decreases the need for other analgesics, when compared with control (89390,90012,90015,98287,103728,114676,114677,114678). However, some data are conflicting. In a meta-analysis of 7 trials, IV magnesium was not associated with lower pain scores over the first 48 hours postoperatively. The reasons for these discrepant findings are unclear but may be explained by differences in magnesium regimens, anesthesia protocols, and surgical populations studied. Additionally, IV magnesium appears to be less effective than dexmedetomidine (105082). Two moderate-sized clinical studies in patients undergoing total knee arthroplasty in China show that adding magnesium sulfate 2.5 mg/mL to the periarticular infiltration analgesia (PIA) cocktail or administering IV magnesium sulfate 40 mg/kg before anesthesia induction then as a 15 mg/kg infusion during surgery reduces pain scores, increases comfort levels, limits and delays the use of postoperative opioids, prolongs analgesia, and reduces markers of inflammation when compared with the usual PIA cocktail or control (111181,113677). Administering magnesium intravenously also seems to be helpful for pain control after hysterectomy. A 3-gram IV bolus of magnesium sulfate followed by an infusion of 0.5 grams per hour for 20 hours has been used. Lower doses were not effective (6848). In males undergoing laparoscopic radical resection for gastrointestinal cancer, administering IV magnesium intraoperatively, as a loading dose of 40 mg/kg followed by 15 mg/kg/hour through the end of surgery, reduces postoperative catheter-related bladder discomfort and analgesic requirements, when compared with placebo (112783). However, IV magnesium might not alleviate postoperative pain in children. Two small clinical studies show that administering a magnesium IV infusion does not reduce pain when compared with saline in children after tonsillectomy or after elective strabismus surgery (98282,105077).
• Premenstrual syndrome (PMS). Taking magnesium orally seems to relieve symptoms of PMS. Details: There is some evidence that magnesium supplementation can improve symptoms, including mood changes and fluid retention, in some patients with PMS (1187,1188,6847). Doses used include magnesium oxide 333 mg daily for 2 menstrual cycles, or magnesium pyrrolidone carboxylic acid equivalent to 360 mg elemental magnesium three times daily, from the 15th day of the menstrual cycle until onset of menstrual flow (1187,1188). Taking magnesium orally in a dose of 360 mg (elemental magnesium) three times daily for 2 months seems to prevent premenstrual migraine (1186,6847). A combination of magnesium 200 mg daily plus vitamin B6 50 mg daily seems to reduce anxiety-related premenstrual symptoms, including nervous tension, mood swings, irritability, and anxiety, when compared with placebo (8555).
• Vasospastic angina. Intravenous magnesium seems to prevent coronary spasm in patients with this condition. Details: Clinical research shows that administration of intravenous magnesium sulfate 65 mg/kg infused over 20 minutes dilates coronary arteries and suppresses acetylcholine-induced coronary spasms when compared with infusion of a dextrose solution in patients with vasospastic angina (8091).

POSSIBLY INEFFECTIVE

• Altitude sickness. Taking magnesium citrate orally does not seem to reduce acute altitude sickness risk. Details: Clinical research shows that taking magnesium citrate 1200 mg daily orally in three divided doses, beginning 3 days prior to mountain ascent and continuing until mountain descent, does not reduce the risk of acute altitude sickness when compared with placebo (60801).
• Athletic performance. Taking magnesium orally does not seem to improve energy or endurance during athletic activity. Details: Most evidence suggests that taking magnesium orally doesn't increase energy and endurance during athletic activity. Magnesium oxide, aspartate, and orotate salts do not seem to improve exercise performance when used alone or in combination with potassium, vitamin B6, or zinc (2825,2826,2828,2829,2830,60751,113655).
• Bronchiolitis. Intravenous or nebulized magnesium is not beneficial in infants with this condition. Details: Clinical research shows that administering a single IV dose of magnesium sulfate 100 mg/kg to infants with acute bronchiolitis does not improve, and may actually worsen, symptoms when compared with placebo (97482). A clinical study in infants with moderate to severe bronchiolitis shows that adding nebulized magnesium sulfate 40 mg/kg to nebulized epinephrine does not reduce hospital stay or the need for ventilator or oxygen support when compared with epinephrine alone (99317). Oral magnesium has not been evaluated for this use.
• Chemotherapy-induced peripheral neuropathy. Research on the effects of intravenous infusions of magnesium and calcium for preventing oxaliplatin neurotoxicity are inconsistent, but higher quality studies seem to show no benefit. Details: Pooled analyses of cohort studies and clinical trials show that calcium and magnesium infusions can decrease the incidence of severe oxaliplatin-induced neurotoxicity (90028,90029,90031). However, when only clinical trials are considered, the infusions do not appear to be helpful (90005,90029,90031,96474,96479).
• Complex regional pain syndrome. Intravenous magnesium is not beneficial in complex regional pain syndrome type 1. Details: Clinical research shows that receiving magnesium sulfate 70 mg/kg intravenously at the rate of 25 mL/hour for 4 hours each day for 5 days does not improve pain or level of impairment when compared with placebo in patients with chronic complex regional pain syndrome type 1 (89395).
• Emergence delirium. The majority of small clinical studies in adults and children undergoing various surgeries suggest that intravenous (IV) magnesium doesn't reduce the risk of emergence delirium. However, most clinical studies in adults suggest that IV magnesium reduces emergence agitation. Details: A small clinical study in adults undergoing surgery for endovascular aortic aneurysm repair shows that administering IV magnesium 30 mg/kg as a loading dose, followed by a 10 mg/kg/hour infusion for the duration of surgery, does not improve agitation or delirium scores when compared with administering saline (111182). Similarly, a small clinical study in children ages 2-5 years undergoing elective strabismus surgery shows that administering IV magnesium during anesthesia does not seem to prevent the occurrence of emergence delirium when compared with administering saline (105077). In a meta-analysis of 8 clinical trials in children aged 2-16 years undergoing general anesthesia for oral or ophthalmic surgery, giving IV magnesium as a 30 mg/kg loading dose followed by a 10 mg/kg/hour infusion, or as a single dose of 15-30 mg/kg, does not reduce emergence delirium scores, and may actually prolong emergence times (108729). However, there is some conflicting evidence. In patients undergoing radical mastectomy, giving intraoperative magnesium sulfate 30mg/kg over 1 hour, followed by 10 mg/kg/hour until the end of surgery, reduces emergence agitation (odds ratio 0.26) when compared with placebo (112781).
• Menopausal symptoms. Oral magnesium oxide does not seem to be beneficial for menopausal hot flashes. Details: A small, low quality study in postmenopausal patients with a history of breast cancer shows that taking magnesium oxide 400-800 mg orally daily reduces hot flashes when compared with baseline (102454). However, a larger, higher quality clinical study using magnesium oxide 800-1200 mg daily did not show any benefit when compared with placebo (98290).
• Muscle cramps. Oral magnesium does not seem to improve muscle cramp frequency or intensity. Details: Meta-analyses of small clinical trials show that magnesium supplementation for 3-6 weeks does not decrease the frequency or intensity of skeletal muscle cramps, whether the cramps are idiopathic or due to liver cirrhosis or pregnancy, when compared with placebo (90022,104395).
• Sickle cell disease. Intravenous magnesium does not add any benefit to standard therapy for sickle cell disease in children. Details: Clinical research shows that giving magnesium sulfate 40-100 mg/kg (maximum of 2 grams per dose) intravenously every hour for 6-8 doses as an adjunct to standard therapy does not decrease hospital stay, pain, or opioid use, or improve quality of life, when compared with standard therapy and placebo in children with sickle cell disease (89399,98283,101356). Oral magnesium has not been evaluated for this purpose.
• Stillbirth. Magnesium administered during pregnancy does not reduce stillbirth risk. Details: A meta-analysis of clinical research shows that magnesium supplementation does not significantly decrease the risk of stillbirths when administered during pregnancy (60925,60978).
• Tetanus. Intravenous magnesium sulfate does not seem to improve outcomes in patients with this condition. Details: A meta-analysis of clinical research shows that intravenous magnesium sulfate does not reduce mortality when compared with placebo or diazepam in patients with tetanus (61020). While some research shows that magnesium reduces the duration of hospitalization and the need for ventilation when compared with diazepam (61170), magnesium does not seem to improve these outcomes when compared with placebo (60860).
• Traumatic brain injury (TBI). Magnesium does not improve clinical outcomes in patients with moderate to severe TBI. Its effect in patients with concussions is unclear. Details: A meta-analysis of four clinical trials shows that treatment with magnesium does not significantly improve neurological outcomes or reduce the risk of mortality when compared with placebo in patients with moderate to severe TBI (60905). A small observational cohort study in adolescents with concussions has found that adding oral magnesium 400 mg twice daily for 5 days to standard treatment with acetaminophen and ondansetron is associated with a trend toward reduced symptom severity when compared with standard treatment alone (104401). The validity of this study is limited by its observational nature and small cohort size.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. Intravenous magnesium does not seem to help reduce symptoms of alcohol withdrawal but may reduce the duration of alcoholic delirium. Details: Preliminary clinical research shows that administration of four intramuscular injections of magnesium sulfate 2 grams at 6-hour intervals does not reduce symptoms of alcohol withdrawal when compared with saline (61063). A small observational study in patients with alcoholic delirium has found that administering magnesium sulfate IV 50 mg/kg every 8 hours, in addition to usual sedation, is associated with a reduction of delirium by approximately 2 days, or 4 days when given every 12 hours in addition to dexmedetomidine, when compared with usual sedation alone (111180). However, half of patients had hypomagnesemia at baseline; it is unclear if effects would be similar for patients with normal magnesium levels. Oral magnesium has not been evaluated for this purpose.
• Allergic rhinitis (hay fever). Although there has been interest in using oral magnesium for allergic rhinitis, there is insufficient reliable information about the clinical effects of magnesium for this purpose.
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral magnesium is beneficial in children with ADHD. Details: Children with ADHD seem to have lower magnesium levels in their blood and hair (9969,100262,100263). A small clinical study in children aged 7-12 years with ADHD and magnesium deficiency shows that taking magnesium aspartate and lactate 6 mg/kg daily for 6 months might improve hyperactivity and magnesium levels when compared with control (1189). Another small clinical study in children with ADHD but without magnesium deficiency shows that taking magnesium 6 mg/kg daily along with vitamin D 50,000 IU weekly for 8 weeks may modestly improve emotional problems, but not inattention or hyperactivity, as measured on the strength and difficulties questionnaire (SDQ), when compared with placebo (105914).
• Back pain. It is unclear if oral or intravenous magnesium is beneficial for acute or chronic back pain in adults. Details: One open-label clinical study in adults with acute low-back pain shows that taking magnesium 365 mg once daily in addition to taking etodolac 400 mg twice daily for 10 days does not further reduce pain when compared with taking etodolac alone (105913). Magnesium has also been tried for chronic back pain. A small clinical study in patients with chronic low-back pain shows that receiving magnesium sulfate 1 gram in 250 mL normal saline intravenously every 4 hours for 2 weeks, followed by magnesium gluconate 100 mg and magnesium oxide 400 mg by mouth daily for 4 weeks, reduces pain severity when compared with placebo (90035). It is unclear if oral magnesium used alone is beneficial.
• Bariatric surgery complications. It is unclear if oral magnesium supplementation improves metabolic parameters after bariatric surgery. Details: A retrospective study of over 3000 post-bariatric surgery patients suggests that those who take oral magnesium supplements providing 100-450 mg elemental magnesium daily may have improved metabolic parameters over 4 years of follow-up. When patients taking magnesium supplements were compared with those not taking supplements, 11% and 18% had type 2 diabetes, respectively, 30% and 42% had hypertension, respectively, and 16% and 23% had elevated low-density lipoprotein (LDL) cholesterol levels, respectively. For patients with hypomagnesemia at baseline, supplementation seemed to result in greater benefits (108968).
• Bipolar disorder. Taking magnesium orally might improve manic symptoms in some people with bipolar disorder; however, it is unclear how it compares to current standard of care. Details: One preliminary clinical study shows that magnesium 40 mEq daily (Magnesiocard) for 32 weeks has similar effects to lithium in up to 50% of patients treated for rapid cycling bipolar affective disorder (61022). Another preliminary clinical study shows that magnesium oxide 375 mg orally daily plus verapamil 80 mg taken four times daily reduces manic symptoms more effectively than verapamil alone in patients with mania (60742).
• Cancer-related neuropathic pain. It is unclear if intravenous magnesium is beneficial for this condition. Details: Single 500 mg to 1 gram doses of magnesium sulfate seem to relieve neuropathic pain for up to four hours when compared to baseline (6846). The validity of this finding is limited by the lack of a comparator group.
• Cardiac arrest. Intravenous magnesium does not seem to be helpful in cardiac arrest; however, the risk of sudden cardiac death seems to be inversely correlated to higher plasma magnesium levels or dietary intake. It is unclear if magnesium supplementation is associated with similar risk reduction. Details: Administering magnesium intravenously doesn't seem to improve successful resuscitation in people with cardiac arrest (1190). However, higher plasma magnesium levels and higher dietary magnesium intake might reduce the risk of sudden cardiac death, possibly by protecting against fatal ventricular arrhythmias. In the Nurses' Health Study, the risk of sudden cardiac death was 77% lower in females with the highest quartile of plasma magnesium levels when compared with the lowest quartile. Also, the risk was 37% lower in females with the highest quartile of dietary magnesium intake when compared with the lowest quartile (17132).
• Cardiovascular disease (CVD). Evidence regarding the effect of dietary magnesium on CVD risk is conflicting. Details: Epidemiological research in some populations shows that increased dietary magnesium intake is associated with decreased mortality due to strokes, coronary heart disease, ischemic heart disease, and heart failure, but other epidemiological research does not show any effect on these risks (89391,90003,90009,90030,90036,103735). Reasons for the discrepancies may be related to serum levels of magnesium at baseline, risk of cardiovascular disease at baseline, use of concomitant medications such as diuretics, or the presence of concomitant conditions such as kidney dysfunction. A population analysis conducted in Denmark has found that magnesium intake from drinking water may be associated with cardiovascular mortality. The overall risk of cardiovascular death and death due to stroke was reduced by 4% in the lowest 3 quintiles of intake when compared with the highest quintile. However, the risk of death due to acute myocardial infarction was increased by 22% in the lowest quintile when compared with the highest (108726). The relevance of these results is unclear, given that the main dietary source of magnesium is food rather than drinking water.
• Chronic fatigue syndrome (CFS). Limited evidence suggests that magnesium may help improve CFS symptoms, but this is controversial. Details: In people with low red blood cell magnesium, there is some evidence that intramuscular injections of 1 gram magnesium sulfate given once weekly for 6 weeks might improve CFS symptoms (7556). However, there is additional evidence that most patients with CFS have normal magnesium stores, and measurement of red cell magnesium is a poor indicator of total magnesium stores (7557,8084,8085,8086,8087).
• Chemotherapy-induced leukopenia. It is unclear if oral magnesium is beneficial in pediatric patients at risk for cisplatin-induced febrile neutropenia. Details: A small clinical study in children with solid tumors aged 9 years and older shows that taking magnesium 250 mg daily while receiving cisplatin-based chemotherapy reduces febrile neutropenia by 47% and septic shock by 57% when compared with not receiving magnesium. Results from this study suggest that four pediatric patients need to take oral magnesium to avoid one case of febrile neutropenia (104394).
• Chemotherapy-induced nephrotoxicity. It is unclear if intravenous magnesium is beneficial for chemotherapy-induced nephrotoxicity. Details: A meta-analysis of several lower quality clinical studies in adults in Japan with cancer receiving cisplatin shows that pretreatment with intravenous magnesium sulfate 5 to 20 mEq reduces the odds of chemotherapy-induced nephrotoxicity in a dose-dependent manner when compared to standard hydration therapy (115726). The validity of these findings is limited by heterogenous methods between clinical trials, including types of cancer, definitions of nephrotoxicity, and use of other nephroprotective therapies.
• Chronic obstructive pulmonary disease (COPD). Intravenous, but not nebulized, magnesium may be helpful in acute exacerbations of COPD. Details: Administering magnesium sulfate intravenously, 1.2-2.5 grams over 20 minutes, might be helpful for treating acute exacerbations of COPD (1208,6844,103733). Also, giving magnesium sulfate 2 grams intravenously seems to improve exercise capacity when compared with placebo (89384). A meta-analysis of studies using intravenous magnesium sulfate for COPD exacerbations shows that it reduces hospital admission and mean length of stay and improves dyspnea scores when compared with placebo. Based on the relative risk identified in the included studies, seven patients would need to receive intravenous magnesium to prevent one hospitalization. However, intravenous magnesium sulfate does not change the need for non-invasive ventilation and the available research did not evaluate intensive care unit (ICU) admission (108967). Nebulized magnesium has also been evaluated. In patients experiencing a COPD exacerbation, clinical research shows that administering nebulized magnesium sulfate with albuterol three times at 30-minute intervals does not improve pulmonary function as measured by the forced expiratory volume in 1 second (FEV1) when compared with placebo (89393). Also, a meta-analysis of a small number of low-quality studies shows that nebulized magnesium does not reduce hospital admission or the need for ventilatory support, although it might modestly improve dyspnea scores and reduce ICU admissions, when compared with placebo (108967).
• Cluster headache. It is unclear if a single intravenous dose of magnesium sulfate is beneficial for cluster headaches. Details: Administering magnesium sulfate intravenously, 1 gram over 5 minutes, seems to improve cluster headaches when compared with baseline(1184). The validity of this finding is limited by the lack of a comparator group.
• Cognitive impairment. It is unclear if oral magnesium is beneficial for cognitive impairment. Details: A large observational study in adults with end-stage renal disease on hemodialysis suggests that serum magnesium levels of 20.2-22.3 mg/dL are associated with the lowest odds of mild cognitive impairment, while serum magnesium levels below and above that range of values are associated with increased odds of mild cognitive impairment (111695).
• Coronary heart disease (CHD). It is unclear if magnesium supplementation is beneficial for CHD. Details: Clinical research shows that magnesium oxide 800-1200 mg daily for 3 months reduces platelet-dependent thrombosis by 35% when compared with placebo in patients with CHD (60759). It is unclear if this effect improves clinical outcomes. The effect of magnesium supplementation on coronary artery calcium has also been studied. A meta-analysis of 3 clinical studies in 196 patients with chronic kidney disease (CKD) shows that taking magnesium or increasing the concentration of magnesium in dialysate does not improve coronary artery calcification (CAC) scores when compared with standard therapy. However, magnesium reduced carotid intima-media thickness (111179). Similarly, a large clinical study in patients with CKD shows that taking slow-release magnesium hydroxide (Mablet, Denmark) 360 mg twice daily for 12 months does not slow the progression of CAC scores when compared with placebo (111178). This study may not have been adequately powered to detect a difference between groups.
• Coronavirus disease 2019 (COVID-19). It is unclear if oral magnesium is beneficial for COVID-19. Details: A small clinical study in patients hospitalized with moderate COVID-19 shows that taking magnesium 300 mg daily for the duration of hospitalization reduces the number of patients requiring oxygen therapy but not the duration of hospital stay when compared with placebo (114680).
• Depression. It is unclear if magnesium is beneficial for the treatment or prevention of depression in adults. Details: Some population research shows that dietary intake of elemental magnesium between 76-360 mg daily is associated with a reduced risk of depression, but there was no association with greater amounts of magnesium, and other population research shows no association at any intake level (96480,98289). For treatment of mild to moderate depression, one preliminary clinical study shows that taking magnesium chloride 2 grams orally daily for 6 weeks reduces depression scores by 56% and anxiety scores by about 52% when compared to baseline (96477). The validity of these findings is limited by the lack of a comparator group. However, a small clinical study in adults with recurrent depression shows that taking magnesium aspartate 120 mg daily for 8 weeks, along with fluoxetine, does not improve depression scores when compared with patients taking fluoxetine and placebo (111185). Similarly, a very small crossover clinical study in adults with mild or moderate treatment-resistant depression shows that administering a single dose of IV magnesium sulfate 4 grams does not improve depression scores when compared with an infusion of 5% dextrose (96481). However, scores were evaluated 24 hours post-infusion which may be too soon to detect improvement. Guidelines from The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce state that elemental magnesium in doses of 100-400 mg is not recommended for adjunctive or monotherapy use in patients with depression (110318).
• Diabetic foot ulcers. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with grade 3 diabetic foot ulcers shows that taking magnesium oxide 250 mg plus vitamin E 400 IU daily for 12 weeks modestly reduces ulcer size when compared with placebo (101436). It is unclear if this effect is due to magnesium, vitamin E, or the combination.
• Exercise-induced muscle soreness. It is unclear if oral magnesium reduces muscle soreness in adults after resistance training. Details: A very small study in healthy adults, ages 19-23, shows that taking magnesium glycinate 350 mg daily for 10 days seems to reduce muscle soreness after bench press exercise when compared with placebo (104399).
• Fetal and premature infant mortality. It is unclear if antenatal intravenous (IV) magnesium sulfate administration reduces the risk of fetal and premature infant mortality. Details: Two meta-analyses of up to 7 clinical studies in patients at risk of preterm birth shows that antenatal IV magnesium sulfate administration does not reduce the risk of fetal or neonatal death when compared with placebo (114675,114681).
• Fibromyalgia. It is unclear if oral magnesium is beneficial for this condition. Details: A small clinical study shows that taking magnesium chloride orally 100 mg once daily for one month reduces mild to moderate, but not severe, stress associated with fibromyalgia when compared with placebo. It also reduces pain levels, but not to a clinically significant extent, and it does not affect sleep, fatigue, or quality of life (108964). Another small clinical study shows that taking magnesium citrate 300 mg daily for 8 weeks improves some symptoms of fibromyalgia, such as number of tender points and depression, when compared to baseline (89385). The validity of this finding is limited by the lack of a comparator group. A small clinical study shows that taking a combination of magnesium hydroxide and malic acid (Super Malic tablets) orally decreases fibromyalgia-related pain and tenderness in some patients when compared with placebo (3262). It is unclear if this effect is due to magnesium, malic acid, or the combination.
• Fractures. Population research suggests that higher intakes of magnesium may reduce fracture risk. Details: Observational research has found that higher dietary and supplemental magnesium intake is associated with a 34% lower odds of fracture when compared with lower magnesium intake (101395).
• Gastric cancer. Population research suggests that higher intakes of magnesium may reduce gastric cancer risk. Details: Observational research has found that higher dietary and supplemental magnesium intake is not associated with a reduced risk for gastric cancer when compared with lower intake (103730).
• Hearing loss. Oral magnesium may prevent and improve hearing loss due to environmental factors or loud noises. Details: Clinical research in healthy military recruits shows that taking magnesium aspartate 167 mg daily for 2 months prevents hearing loss from exposure to loud noises during basic military training when compared with placebo (1205). Also, in patients with acute-onset hearing loss that was not caused by environmental factors, taking magnesium aspartate 167 mg daily for 8 weeks seems to improve hearing loss when compared with placebo (60813).
• Hypertension. Oral magnesium supplementation may modestly reduce blood pressure, although these changes are not likely to be considered clinically significant. Details: Most research shows that taking oral magnesium supplements in daily doses that are at least as high as the Recommended Dietary Allowance (RDA) for adults and up to 1000 mg daily can lower diastolic blood pressure by about 2 mmHg in adults with or without hypertension (1192,1199,9465,15165,18111,96482). Significantly lower doses do not seem to have this effect (1180,1195,1197,8098). The effect of magnesium on systolic blood pressure is conflicting. Two meta-analyses shows that taking magnesium 212-970 mg daily does not lower systolic blood pressure in patients with or without hypertension (15165,115728). However, additional meta-analyses show that taking magnesium 120-970 mg daily can lower systolic blood pressure in a dose-dependent manner by about 2-4 mmHg in patients with or without hypertension (18111,96482). The reasons for these discrepant findings are unclear but may be due to heterogenous methods, including dose and duration among clinical studies. In 2022, the US Food and Drug Administration (FDA) approved a qualified health claim stating that inconsistent and inconclusive evidence suggests that diets with adequate magnesium may reduce the risk of high blood pressure. Products bearing this claim must provide at least 84 mg of magnesium daily, but no more than 350 mg daily (107451).
• Hypokalemia. It is unclear if intravenous or oral magnesium is beneficial for hypokalemia in patients with normal magnesium levels. Details: A preliminary retrospective observational study in patients with hypokalemia and unknown serum magnesium levels has found that administering oral or intravenous magnesium is not associated with improved time to normalization of serum potassium levels when compared with no magnesium treatment (110049). However, hypokalemia with concurrent hypomagnesemia can impede potassium repletion and exacerbate hypokalemia-induced rhythm disturbances. Standard of care in patients with hypokalemia and known hypomagnesemia includes prompt treatment with magnesium (110063).
• Impaired glucose tolerance (prediabetes). It is unclear if oral magnesium is beneficial for prediabetes. Details: Preliminary clinical research in patients with prediabetes shows that taking magnesium oxide 250 mg orally daily for 12 weeks does not improve fasting blood glucose levels, insulin resistance, or glycated hemoglobin (HbA1C) levels when compared with placebo. Taking magnesium also did not affect blood pressure, body weight, triglyceride levels, or low-density lipoprotein cholesterol levels; however, it did modestly improve high-density lipoprotein cholesterol levels (110053).
• Insomnia. Oral magnesium may modestly improve sleep complaints in adults, but evidence is conflicting. Details: A meta-analysis of two small clinical studies in healthy older adults with or without insomnia suggests that taking magnesium reduces the time to fall asleep by an average of 17 minutes when compared with placebo (105917). However, it does not increase the time spent asleep. Also, these findings are limited by imprecision and a high risk of bias. Studies included in the analysis used elemental magnesium 500-729 mg daily (as magnesium oxide) for up to 8 weeks (102458,105917). Another small clinical study in patients with poor sleep quality and low magnesium status shows that taking elemental magnesium 320 mg (as magnesium citrate) in divided doses daily for 7 weeks does not improve sleep quality, as measured by the Pittsburgh Sleep Quality Index (PSQI), when compared with a sodium citrate placebo (102456). Magnesium has also been evaluated in combination with other ingredients. A very small crossover clinical study in patients aged 18-40 years without a sleep disorder shows that taking a combination of magnesium 300 mg, L-tryptophan 1000 mg, glycine 3000 mg, tart cherry 220 mg, and theanine 200 mg for 3 days reduces the time to fall asleep by about 24 minutes, increases total time asleep by about 22 minutes, and improves sleep efficiency, but does not improve the total time in bed or wakefulness after falling asleep when compared with cellulose placebo (111184). Another small crossover clinical study in adults with sleep disturbances shows that taking a combination of magnesium 200 mg and melatonin nightly for 4 weeks improves sleep quality, as measured by the PSQI, reduces the length of time it takes to fall asleep by about 17 minutes, and improves some other measures of sleep, such as sleep efficiency and number of awakenings, when compared with placebo. However, despite these improvements, overall sleep quality was still categorized as poor after the intervention (113670). It is unclear if these effects are due to magnesium, other ingredients, or the combination.
• Intraventricular hemorrhage. It is unclear if antenatal intravenous (IV) magnesium sulfate can reduce the risk for intraventricular hemorrhage in neonates. Details: A meta-analysis of clinical research in premature infants shows that if the mother received antenatal intravenous magnesium sulfate, the infant had a non-significant trend toward a reduced risk of intraventricular hemorrhage when compared with infants whose mothers received placebo (103727). This analysis may have been insufficiently powered to detect a difference between groups. Another meta-analysis of up to 6 clinical studies, some of which are included in the previously referenced meta-analysis, in patients at risk of preterm birth shows that maternal antenatal (IV) magnesium sulfate administration does not reduce the risk of intraventricular hemorrhage, but does reduce the risk of severe intraventricular hemorrhage by about 24% when compared with placebo (114681).
• Kidney stones (nephrolithiasis). Taking magnesium orally may prevent the recurrence of kidney stones, although evidence is conflicting. Details: Prophylactic treatment with magnesium hydroxide, 200 mg twice daily for one year, followed by 500 mg daily for another year, might decrease the recurrence rate of calcium stone formation (2007). However, magnesium oxide does not seem to benefit patients considered to be recurrent calcium stone formers when compared with placebo, no treatment, or chlorthalidone (8097,38501,61199). Magnesium oxide 300 mg in combination with vitamin B6 10 mg daily seems to decrease urinary oxalate levels in people with hyperoxaluria who have previously had kidney stones (1201), but it is unclear if this effect translates into a reduced incidence of kidney stones.
• Liver cancer. Increased dietary magnesium intake is linked with a lower risk of liver cancer. Details: Observational research in retired older Americans has found that higher dietary magnesium intake is associated with a 35% lower risk of liver cancer when compared with lower intake. This association was especially strong in persons who were moderate or heavy alcohol users (105080).
• Lung cancer. Supplemental or dietary magnesium intake does not seem to reduce the risk of lung cancer. Details: A large epidemiological cancer screening trial with a mean follow-up of over 12 years suggests there is no association between dietary or supplemental magnesium intake and the risk of lung cancer. However, dietary magnesium seems to play an important yet unclear role in lung cancer prevention when taken as part of the diet with alpha-carotene, vitamin C, vitamin E, lycopene, selenium, lutein, and zeaxanthin (112096).
• Migraine headache. Oral magnesium may help prevent migraine in some adults and children. Also, intravenous magnesium may help treat migraine in adults, but evidence is conflicting. Details: A meta-analysis of 4 low-quality clinical studies, in adults with migraine shows that magnesium 122-600 mg daily for 4-16 weeks modestly reduces migraine frequency and severity when compared with placebo(115730). However, clinical significance is unclear, and the validity of these findings is limited by heterogeneous methods between clinical trials, including type of magnesium formulation and dose, patient population, and duration. In contrast, one small clinical study shows that taking magnesium does not reduce migraine frequency and severity by at least 50% in adults when compared with placebo (10661). Limited evidence suggests that adding oral magnesium to conventional treatment may also be beneficial. A clinical study in adults with migraine living in Iran shows that taking magnesium oxide 250 mg twice daily in addition to sodium valproate 200 mg twice daily for 12 weeks modestly reduces severity and duration of migraine, but not migraine frequency, when compared with taking sodium valproate alone (105915). It is unclear if these improvements would be considered clinically significant. For treatment of migraine, some adults with normal magnesium levels respond to intravenous (IV) magnesium sulfate 1 gram over 5 minutes, but most patients who benefit have low magnesium levels at baseline (1185,6844). Effects of IV magnesium in patients with unknown magnesium levels are conflicting. Some preliminary clinical research shows that magnesium 1-2 grams IV alleviates acute migraine for up to 2 hours, but other research has found no benefit (89388,97493,98285). In children, treatment with magnesium oxide orally 15 mg/kg daily in 3 divided doses for up to 16 weeks reduces the frequency and severity of migraine headaches when compared with placebo (10663). However, adding magnesium sulfate 400 mg orally daily to ibuprofen or acetaminophen does not further reduce migraine severity in children (89396).
• Miscarriage. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in pregnant adults with threatened miscarriage between the 6th and 13th week of gestation shows that taking a specific combination product (DAV HA, Lo.Li pharma s.r.l) containing magnesium 450 mg, alpha-lipoic acid, hyaluronic acidvitamin B6, and vitamin D daily in combination with conventional treatment of vaginal progesterone over 2 weeks of observation results in a faster resorption of the subchorionic hematoma and faster decrease of patient-reported vaginal bleeding, abdominal pain, and uterine contractions when compared with vaginal progesterone alone (113893). It is unclear if these effects are due to magnesium, other ingredients, or the combination. Additionally, the validity of these findings is limited by the lack of a placebo in the control group.
• Myocardial infarction (MI). Research on the effects of intravenous or oral magnesium after myocardial infarction are conflicting. Details: Administering magnesium intravenously doesn't seem to reduce mortality after an acute MI (8999,13357,13358,13359,13360,19990,60872,61082), although there is some conflicting evidence from a meta-analysis of clinical research that shows that intravenous magnesium sulfate may reduce short-term mortality by 55% when compared with placebo (60795,60895). Clinical research with oral magnesium supplementation has found no benefit (1198,6844).
• Neonatal encephalopathy. Intravenous magnesium may improve short-term outcomes in neonates with encephalopathy. Details: A meta-analysis of clinical research shows that intravenous magnesium may improve short term outcomes of neonatal encephalopathy (hypoxic ischemic encephalopathy, HIE). However, long term outcomes are not affected (90025).
• Nocturnal leg cramps. It is unclear if oral magnesium is helpful for nocturnal leg cramps. Details: Some clinical research in adults with nocturnal leg cramps shows that taking magnesium oxide 865 mg daily at bedtime for 4 weeks does not reduce the frequency of leg cramping episodes when compared with placebo (96478). However, four weeks may be too short a time to see a benefit. In other clinical research, taking oral magnesium oxide monohydrate 226mg daily at bedtime for 60 days reduces the frequency of leg cramps when compared with placebo. This reduction was not seen after 30 days. Magnesium also reduced cramp duration and improved sleep quality, but did not affect pain scores, at 60 days when compared with placebo (106919).
• Nonalcoholic fatty liver disease (NAFLD). Oral magnesium hydroxide has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with NAFLD shows that taking magnesium hydroxide 150 mg and L-carnitine 2000 mg daily for 16 weeks does not improve liver stiffness scores when compared with baseline or controls who took placebo for 8 weeks followed by this magnesium and L- carnitine combination for 8 weeks. Taking magnesium and L-carnitine also did not improve levels of aspartate aminotransferase (AST) or alanine transaminase (ALT) when compared to baseline (111177).
• Obesity. Evidence on the use of magnesium for weight loss in obese patients is conflicting; any benefit is likely small at best. Details: A meta-analysis of 7 clinical studies in obese patients shows that taking magnesium reduces body mass index (BMI) by 0.3 when compared with control (103723). Another meta-analysis of 7 studies in obese patients shows that while magnesium supplementation does not reduce weight, it reduces waist circumference by 2 cm when compared with placebo (103729). Interestingly, subgroup analyses did not find that the dose of magnesium or baseline magnesium levels impacted effectiveness. One subgroup analysis found that magnesium supplementation lasting 12 weeks or less seemed to be more beneficial for obesity than supplementation lasting longer than 12 weeks (103723).
• Overall mortality. It is unclear if oral or IV magnesium reduces the risk of overall mortality. Details: A meta-analysis of heterogeneous observational studies has found that increased dietary magnesium intake, but not supplemental magnesium intake, is associated with a modestly reduced risk of overall mortality (105073). A meta-analysis of 3 small, low-quality clinical studies in ICU patients shows that administering IV magnesium 24-30 mmol or as a target-directed dose for 3 days reduces overall mortality when compared with patients who did not receive magnesium (111290). However, some studies included patients with hypomagnesemia; it is unclear if effects would be similar for patients with normal levels of magnesium.
• Osteoarthritis. Population research has not found a link between magnesium intake and osteoarthritis risk. Details: Observational research has found that dietary and supplemental magnesium intake is not associated with the risk of developing osteoarthritis (101395).
• Pain (acute). It is unclear if locally injected or intravenous magnesium is helpful for acute pain. Details: Preliminary clinical research in patients with renal colic shows that intravenous (IV) magnesium sulfate, 50 mg/kg infused over 20 minutes, is as effective as IV morphine sulfate 0.1 mg/kg for controlling acute renal pain at 20 minutes after the dose (107367). Magnesium has also been evaluated in a dental procedure. A single-center clinical study in India in adults with irreversible pulpitis requiring a root canal shows that a local injection of 0.2 mL of 10% magnesium sulfate with lidocaine and epinephrine reduces perioperative pain when compared to lidocaine with epinephrine alone (115729).
• Pain (chronic). Population research suggests that higher intakes of magnesium may modestly reduce the risk for chronic pain. Details: A cross-sectional observational study has found that increased magnesium intake is associated with a 7% to 8% reduced risk for chronic pain. The association was found to be stronger in females than in males (103732).
• Parturition. It is unclear if topical magnesium is beneficial for labor duration. Details: A single-center clinical study in Iranian adults shows that applying 10 mL of a 50% magnesium sulfate solution directly to the cervix during the active phase of labor reduces the time to vaginal delivery by approximately 1.5 hours and improves the childbirth experience, as reported by patients, when compared with placebo. However, clinical significance is unclear (115727).
• Perioperative anxiety. It is unclear if oral magnesium is beneficial for perioperative anxiety. Details: Preliminary clinical research in adults undergoing open heart surgery shows that taking magnesium oxide 250 mg orally twice daily during hospitalization moderately improves anxiety and depression scores when compared with no magnesium therapy. Magnesium therapy was held for the 2 days immediately following surgery (110054).
• Physical performance. Oral magnesium may modestly improve physical performance in otherwise healthy, elderly females. Details: Clinical research in otherwise healthy elderly females shows that taking a magnesium oxide supplement (Easymag, Sanofi-Aventis) 900 mg daily for 12 weeks modestly improves walking speed and chair stand speed in elderly females when compared with no treatment (90026).
• Polycystic ovary syndrome (PCOS). It is unclear if oral magnesium is beneficial for improving metabolic indices in patients with PCOS. Details: Two small clinical studies in patients with PCOS show that taking magnesium oxide orally, 250 mg daily for 8 weeks, does not affect insulin resistance, beta-cell function, lipid levels, or insulin sensitivity when compared with placebo (103725,105887). Other clinical research in patients with PCOS shows that taking magnesium oxide orally, 250 mg daily for 10 weeks, improves subjective measures of quality of life, fatigue, and emotional functioning, but not objective measures such as alopecia, abnormal uterine bleeding, or acne, when compared with placebo (108965). A clinical study using a combination of magnesium 250 mg with vitamin E 400 mg daily for 12 weeks shows a modest reduction in insulin resistance, insulin levels, and triglyceride levels, but not other lipid levels, when compared with placebo (100264). It is unclear if these beneficial effects are due to magnesium, vitamin E, or the combination.
• Postoperative nausea and vomiting (PONV). It is unclear if intravenous (IV) magnesium is beneficial for PONV due to mixed results from clinical research. Details: A meta-analysis of 5 clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium sulfate intraoperatively reduces PONV (114676). However, a meta-analysis of 20 clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium perioperatively does not reduce the incidence of PONV (114678). A moderate-sized clinical study conducted in China in older adults undergoing total knee arthroplasty shows that administering intravenous magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery reduces the incidence of postoperative vomiting but not postoperative nausea when compared with control (113677). The reasons for these discrepant findings are unclear but may be explained by differences in magnesium regimens, anesthesia protocols, and surgical populations studied.
• Postoperative recovery. It is unclear if intravenous (IV) magnesium is beneficial for postoperative recovery. Details: A moderate-sized clinical study conducted in China in older adults undergoing total knee arthroplasty shows that administering IV magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery does not reduce extubation time, time spent in the post-anesthesia care unit (PACU), or duration of hospital stay when compared with control (113677). Additionally, a meta-analysis of 3 different clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium intraoperatively does not reduce extubation time (114676).
• Postoperative sleep disturbance. It is unclear if oral magnesium is beneficial for postoperative sleep disturbances. Details: Preliminary clinical research in adults undergoing open heart surgery shows that taking magnesium oxide 250 mg orally twice daily during hospitalization moderately improves sleep scores when compared with no magnesium therapy. Magnesium therapy was held for the 2 days immediately following surgery (110054).
• Postoperative sore throat. It is unclear if topical magnesium sulfate is beneficial for reducing sore throat pain after endotracheal intubation. Details: Preliminary clinical research in patients undergoing endotracheal intubation for surgery shows that using a gargle containing magnesium sulfate 20% with lidocaine, 20 minutes before anesthesia induction, is less effective for reducing sore throat pain than a gargle containing dexmedetomidine and lidocaine (112779). The study did not include a comparison to lidocaine alone.
• Pregnancy-related leg cramps. It is unclear if oral magnesium reduces leg cramps during pregnancy; evidence is conflicting. Details: One small clinical study in patients with pregnancy-related leg cramps shows that taking magnesium bisglycinate chelate 300 mg daily for 4 weeks reduces the frequency and intensity of leg cramps when compared with placebo (99318). A smaller clinical study in this population shows that taking a specific mixture of magnesium lactate and citrate (Nycoplus Magnesium) providing elemental magnesium 120 mg in the morning and 240 mg in the evening for 3 weeks reduces the frequency of cramps when compared with placebo (1194). However, not all research agrees. One small clinical study using this same supplement and dose for 2 weeks found no benefit when compared with placebo (17463). It is possible that a 2-week duration of treatment is too short to be beneficial. Finally, a meta-analysis of these studies and one other more recent clinical study shows that taking magnesium does not reduce the frequency or improve the resolution of pregnancy-related leg cramps when compared with placebo (105916). This analysis may not have been adequately powered to detect a difference between treatment groups.
• Pre-procedural sedation. It is unclear if intravenous magnesium is beneficial when administered in addition to other medications used for sedation during surgery. Details: A moderate-sized study of adults aged 65-79 years old undergoing endoscopic retrograde cholangiopancreatography (ERCP) shows that administering a single intravenous bolus of magnesium sulfate 40 mg/kg prior to the procedure reduces intraoperative propofol requirements by about 21% and reduces some peri-procedural adverse events including the incidence of respiratory depression and involuntary movement when compared with control. However, there were no differences in recovery time, hemodynamic parameters, or the incidence of hypotension, bradycardia, perioperative nausea or vomiting, lethargy, or arrythmias (111694). Another moderate-sized study in older adults undergoing total knee arthroplasty shows that administering intravenous magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery does not reduce the need for medications used for anesthesia induction, intraoperative maintenance propofol requirements, or recovery time when compared with control. However, magnesium sulfate does seem to reduce the amount of remifentanil required for intraoperative anesthesia maintenance and increase norepinephrine requirements when compared with control (113677).
• Preterm labor. The use of magnesium sulfate to inhibit uterine contractions in preterm labor (tocolysis) is controversial. However, its use for the purpose of fetal neuroprotection for up to 48 hours is supported by the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine. Details: Magnesium is given intravenously (IV) during preterm labor in an effort to improve fetal neurological outcomes, such as to reduce the risk of cerebral palsy and motor dysfunction in the infant (60915,60927,60931,61001,97485,103734,103754,114681). The typical dosage of magnesium sulfate is 4 grams infused IV over 10-30 minutes, followed by a maintenance infusion of 1-4 grams/hour for 48 hours or until birth. Use beyond 5-7 days has been associated with hypocalcemia and bone abnormalities in the fetus (15,12590,12594). Some meta-analyses of clinical research suggest that magnesium sulfate is more effective at delaying delivery by 48 hours when compared with oxytocin receptor blockers, nitrates, beta-mimetics, and/or placebo (20263,61021). However, an additional meta-analysis of several clinical studies shows that magnesium sulfate 4 or 6 grams IV is not more effective at delaying preterm labor by 48 hours when compared with nifedipine (115639). The reason for these discrepant findings are unclear, but may be related to the heterogenous methods between clinical trials, including dose and duration.
• Pseudoxanthoma elasticum (PXE). It is unclear if oral magnesium is beneficial for PXE. Details: Preliminary clinical research in patients with PXE shows that taking magnesium oxide 800 mg (500 mg of elemental magnesium) twice daily for one year tends to reduce calcification of elastic skin fibers when compared with placebo, but the effect is not statistically significant (101393). This study was limited by small size and insufficient power to detect smaller effects.
• Restless legs syndrome (RLS). It is unclear if oral magnesium is beneficial for RLS. Details: Some observational research has found that hypomagnesemia is associated with RLS; however, not all research agrees (8096,9472). Preliminary clinical research in adults with RLS who are beginning treatment with pramipexole shows that also taking magnesium oxide 250 mg orally daily for 2 months moderately improves RLS scores and sleep quality scores when compared with pramipexole and placebo (110052). Other low-quality clinical research in adults with RLS or periodic limb movement during sleep shows that taking magnesium 12.4 mmol orally in the evening for 4-6 weeks decreases movement and increases sleep when compared with baseline (9466). The validity of this finding is limited by the lack of a comparator group.
• Sarcopenia. It is unclear if oral magnesium is beneficial for the prevention or treatment of sarcopenia. Details: Population research in older adults has found that lower dietary intake of magnesium is associated with sarcopenia. However, the effect of magnesium supplementation on sarcopenia prevention or treatment has not been evaluated (110055). Magnesium has been evaluated in combination with other ingredients for treatment of sarcopenia. A small clinical study in elderly individuals with sarcopenia undergoing a diet and exercise program shows that taking a combination supplement containing magnesium 300 mg, carnosine, hydroxymethylbutyrate, lactoferrin, and sodium butyrate daily for 4 months increases muscle mass, as measured by the skeletal muscle index, and improves measures of muscle function, including handgrip muscle strength, chair test, and walking speed, when compared with placebo (114682). It is unclear if these effects are due to magnesium, other ingredients, or the combination.
• Sepsis. It is unclear if intravenous magnesium is beneficial for sepsis. Details: A very large observational study in patients with sepsis and hypomagnesaemia or normomagnesemia in the intensive care unit (ICU) suggests that administering intravenous magnesium sulfate 2 or 4 grams within 24 hours of admission reduces 28-day all-cause mortality from 25% in patients who did not use magnesium sulfate to 20% in those who were administered magnesium sulfate, regardless of baseline serum magnesium level and other baseline characteristics. Administration of intravenous magnesium sulfate in this population may also reduce ICU mortality by 4%, in-hospital mortality by 3%, and the use of renal replacement therapy by 3% but also seems to increase the length of ICU and hospital stay when compared with patients who did not use magnesium sulfate (113676). The validity of these results is limited by the observational nature of the study.
• Sleep deprivation. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in sleep-deprived recreational athletes shows that taking a combination of magnesium 1350 mg, zinc 90 mg, and vitamin B6 31.5 mg for 3 nights at bedtime does not change sleep quality, subjective sleepiness, mood, or fatigue the next day when compared with placebo (113655).
• Stroke. Increased dietary magnesium may decrease stroke risk, and using a magnesium-containing salt substitute may improve neurological performance post-stroke. However, intravenous magnesium has not demonstrated benefit. Details: Most population research has found that increased dietary intake of magnesium is associated with decreased stroke risk and decreased mortality from stroke (9001,9002,90013,90030,90036,92107,103736). In patients who have had a stroke, a preliminary clinical study shows that using a salt substitute providing the Dietary Reference Intake (DRI) of magnesium and potassium for 6 months improves neurological performance when compared with using regular salt (97491). However, intravenous (IV) magnesium does not seem to be beneficial in patients who have had a stroke. Large prospective clinical trials show that IV magnesium given within 12 hours of acute stroke does not reduce mortality or disability in most patients when compared with placebo. However, one subgroup analysis suggested that IV magnesium might benefit patients with lacunar (non-cortical) stroke (13361,90021). IV magnesium also doesn't seem to reduce cardiovascular complications after acute stroke. A secondary analysis of a clinical trial in patients after ischemic and hemorrhagic stroke shows that giving IV magnesium does not reduce serious cardiac adverse events when compared with placebo (104393). Another secondary analysis of this trial shows that giving IV magnesium prior to arrival at the hospital and within 2 hours of a hemorrhagic stroke does not reduce hematoma volume on hospital arrival, hematoma expansion during hospital admission, or functional outcomes at 3 months (108733).
• Subarachnoid hemorrhage. Intravenous magnesium sulfate may reduce the risk of adverse outcomes in people with subarachnoid hemorrhage, but evidence is conflicting. Details: There is mixed evidence regarding the effect of magnesium sulfate in managing aneurysmal subarachnoid hemorrhage. One meta-analysis of clinical research shows that intravenous magnesium sulfate 64-144 mmol/day for 10-18 days reduces the risk of poor outcomes following aneurysmal subarachnoid hemorrhage, including death, vegetative state, or dependency, by 46% when compared with control (60932). Also, meta-analyses of clinical research show that intravenous magnesium reduces the risk of delayed cerebral ischemia by 27% when compared with placebo (60944,89398). However, these results were not confirmed in other meta-analyses (60973,90034).
• Thrombocytopenia. It is unclear if intravenous magnesium sulfate is beneficial in patients with thrombotic thrombocytopenic purpura (TTP). Details: Addition of intravenous magnesium sulfate as a 6-gram loading dose followed by 6 grams infused over 24 hours for 3 days, to standard treatment for TTP does not reduce the time to normalization of the platelet count, the incidence of TTP-related organ dysfunction, or the recurrence rate, when compared with standard treatment alone (112777). This study may have been underpowered to detect a difference.
• Urinary incontinence. Although there has been interest in using oral magnesium for urinary incontinence, there is insufficient reliable information about the clinical effects of magnesium for this purpose. More evidence is needed to rate magnesium for these uses.

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There is insufficient reliable information available about the safety of betony.

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

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POSSIBLY SAFE ...when used orally and appropriately. Black cohosh has been safely used in some studies lasting up to a year (15036,15158,17091,19553,35908); however, most studies have lasted only up to 6 months (141,4614,4620,7054,9437,9494,13143,13184,14330,14423)(14424,15037,15889,15893,35824,35852,35853,35858,35865,35897)(35902,35904,35946,35964,95525,103269). There is concern that black cohosh might cause liver damage in some patients. Several case reports link black cohosh to liver failure or autoimmune hepatitis (4383,10692,11906,12006,13144,14469,15160,16721,16722,16723)(16724,16725,16726,16727,35857,107906). However, the evidence that black cohosh causes liver damage is not conclusive (17085). Until more is known, monitor liver function in patients who take black cohosh.

PREGNANCY: POSSIBLY UNSAFE
when used orally in pregnant patients who are not at term. Black cohosh might have hormonal effects and menstrual and uterine stimulant effects (15035). Theoretically, this might increase the risk of miscarriage; avoid using during pregnancy. There is insufficient reliable information available about the safety of black cohosh when used to induce labor.

LACTATION: POSSIBLY UNSAFE
when used orally. Black cohosh might have hormonal effects. Theoretically, maternal intake of black cohosh might adversely affect a nursing child (15035). Until more is known, nursing patients should avoid taking black cohosh.

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LIKELY SAFE ...when used orally in amounts typically found in food. Capsicum has Generally Recognized as Safe (GRAS) status in the US (4912). ...when used topically and appropriately (7038,10650,105345). The active capsicum constituent capsaicin is an FDA-approved ingredient used in certain over-the-counter, topical preparations (272).

POSSIBLY SAFE ...when used orally and appropriately, short-term in medicinal amounts. A specific sustained-release chili extract (Capsifen) has been used safely in doses of up to 200 mg daily, for up to 28 days (105196). ...when used intranasally and appropriately, short-term. Capsicum-containing nasal sprays, suspensions, and swabs seem to be safe when applied multiple times over 24 hours or when applied daily or every other day for up to 14 days. Although no serious side effects have been reported in clinical trials, intranasal application of capsicum-containing products can be very painful (14322,14324,14328,14329,14351,14352,14353,14356,14357) (14358,14359,14360,15016,105204). POSSIBLY UNSAFE when used orally, long-term or in high doses. There is concern that long-term use or use of excessive doses might be linked to hepatic or kidney damage, as well as hypertensive crisis (12404,40569,40606). There is insufficient reliable information available about the safety of capsicum when injected.

CHILDREN: POSSIBLY UNSAFE
when used topically in children under 2 years old (272). There is insufficient reliable information available about the safety of capsicum when used orally in children.

PREGNANCY: LIKELY SAFE
when used topically and appropriately (272).

PREGNANCY: POSSIBLY SAFE
when used orally and appropriately, short-term. Capsicum 5 mg daily has been used for up to 28 days during the latter half of the second trimester and the third trimester (96457).

LACTATION: LIKELY SAFE
when used topically and appropriately (272).

LACTATION: POSSIBLY UNSAFE
when used orally. Dermatitis can sometimes occur in infants when foods heavily spiced with capsicum peppers are ingested during lactation (739). Also, observational research suggests that intake of raw capsicum peppers during pregnancy is associated with an increased risk of sensitization to inhalant allergens in children by the age of 2 years (41021).

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There is insufficient reliable information available about the safety of lousewort.

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

(Read more about LOUSEWORT)

LIKELY SAFE ...when used orally and appropriately. Oral magnesium is safe when used in doses below the tolerable upper intake level (UL) of 350 mg daily (7555). ...when used parenterally and appropriately. Parenteral magnesium sulfate is an FDA-approved prescription product (96484).

POSSIBLY UNSAFE ...when used orally in excessive doses. Doses greater than the tolerable upper intake level (UL) of 350 mg daily frequently cause loose stools and diarrhea (7555).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Magnesium is safe when used in doses below the tolerable upper intake level (UL) of 65 mg daily for children 1 to 3 years, 110 mg daily for children 4 to 8 years, and 350 mg daily for children older than 8 years (7555,89396). ...when used parenterally and appropriately (96483).

CHILDREN: LIKELY UNSAFE
when used orally in excessive doses. Tell patients not to use doses above the tolerable upper intake level (UL). Higher doses can cause diarrhea and symptomatic hypermagnesemia including hypotension, nausea, vomiting, and bradycardia (7555,8095).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately. Magnesium is safe for those pregnant and breast-feeding when used in doses below the tolerable upper intake level (UL) of 350 mg daily (7555).

PREGNANCY AND LACTATION: POSSIBLY SAFE
when prescription magnesium sulfate is given intramuscularly and intravenously prior to delivery for up to 5 days (12592,89397,99354,99355). However, due to potential adverse effects associated with intravenous and intramuscular magnesium, use during pregnancy is limited to patients with specific conditions such as severe pre-eclampsia or eclampsia. There is some evidence that intravenous magnesium can increase fetal mortality and adversely affect neurological and skeletal development (12590,12593,60818,99354,99355). However, a more recent analysis of clinical research shows that increased risk of fetal mortality seems to occur only in the studies where antenatal magnesium is used for tocolysis and not for fetal neuroprotection or pre-eclampsia/eclampsia (102457). Furthermore, antenatal magnesium does not seem to be associated with increased risk of necrotizing enterocolitis in preterm infants (104396). There is also concern that magnesium increases the risk of maternal adverse events. A meta-analysis of clinical research shows that magnesium sulfate might increase the risk of maternal adverse events, especially in Hispanic mothers compared to other racial and ethnic groups (60971,99319).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. Tell patients to avoid exceeding the tolerable upper intake level (UL) of 350 mg daily. Taking magnesium orally in higher doses can cause diarrhea (7555). ...when prescription magnesium sulfate is given intramuscularly and intravenously prior to delivery for longer than 5 days (12592,89397,99354,99355). Maternal exposure to magnesium for longer than 5-7 days is associated with an increase in neonatal bone abnormalities such as osteopenia and fractures. The U.S. Food and Drug Administration (FDA) recommends that magnesium injection not be given for longer than 5-7 days (12590,12593,60818,99354,99355).

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ATORVASTATIN (Lipitor) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Taking black cohosh with atorvastatin might increase the risk for elevated liver function tests.  Details In one case report, a patient taking atorvastatin (Lipitor) developed significantly elevated liver function enzymes after starting black cohosh 100 mg four times daily. Liver enzymes returned to normal when black cohosh was discontinued (16725). It is unclear whether the elevated liver enzymes were due to black cohosh itself or an interaction between atorvastatin and black cohosh.

CISPLATIN (Platinol-AQ) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, black cohosh may reduce the clinical effects of cisplatin.  Details Animal research suggests that black cohosh might decrease the cytotoxic effect of cisplatin on breast cancer cells (13101).

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Some research suggests that black cohosh might inhibit CYP2D6, but there is conflicting evidence.  Details Some clinical research suggests that black cohosh might modestly inhibit CYP2D6 and increase levels of drugs metabolized by this enzyme (13536). However, contradictory clinical research shows a specific black cohosh product (Remifemin, Enzymatic Therapy) 40 mg twice daily does not significantly inhibit metabolism of a CYP2D6 substrate in healthy study volunteers (16848). Until more is known, use black cohosh cautiously in patients taking drugs metabolized by CYP2D6.

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black cohosh may alter the effects of estrogen therapy.  Details Some research suggests that black cohosh has estrogenic effects (4618,12064,15035,35831). This may enhance or inhibit the effects of estrogen therapy.

HEPATOTOXIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking black cohosh with hepatotoxic drugs may increase the risk of liver damage.  Details There is concern that black cohosh might be linked to cases of liver failure and autoimmune hepatitis (4383,10692,11906,11909,12006,13144,14469,15160,107906).

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Black cohosh may inhibit one form of OATP, OATP2B1, which could reduce the bioavailability and clinical effects of OATP2B1 substrates.  Details In vitro research shows that black cohosh modestly inhibits OATP2B1 (35450). OATPs are expressed in the small intestine and liver and are responsible for the uptake of drugs and other compounds into the body. Inhibition of OATP may reduce the bioavailability of oral drugs that are substrates of OATP.

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ACE INHIBITORS (ACEIs) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, using topical capsaicin may increase the risk of ACE inhibitor-induced cough.  Details There is one case report of a topically applied capsaicin cream contributing to the cough reflex in a patient using an ACEI (12414). However, it is unclear if this interaction is clinically significant.

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, capsicum may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.  Details In vitro research shows that capsicum might increase the effects of antiplatelet drugs (12406,12407). Also, population research shows that capsicum is associated with an increased risk of self-reported bleeding in patients taking warfarin (12405,20348). However, clinical research shows that taking a single dose of capsaicin (Asian Herbex Ltd.), the active ingredient in capsicum, 400-800 mcg orally in combination with aspirin 500 mg does not decrease platelet aggregation when compared with taking aspirin 500 mg alone. Also, there was no notable effect on measures of platelet aggregation with capsaicin (92990). It is unclear whether capsaicin must be used in more than a single dose to affect platelet aggregation.

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking capsicum with antidiabetes drugs might increase the risk of hypoglycemia.  Details Preliminary clinical research shows that consuming capsicum 5 grams along with a glucose drink attenuates the rise in plasma glucose after 30 minutes by 21%, decreases the 2-hour postprandial area under the curve of plasma glucose by 11%, and increases the 2-hour postprandial area under the curve of plasma insulin by 58% in healthy individuals when compared with placebo (40453,40614). Other clinical research shows that taking capsicum 5 mg daily for 28 days significantly reduces postprandial blood glucose and insulin levels, but not fasting blood glucose and insulin levels, in patients with gestational diabetes (96457).

ASPIRIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking capsicum with aspirin might reduce the bioavailability of aspirin.  Details Animal research shows that acute or chronic intake of capsicum pepper reduces oral aspirin bioavailability (22617). This has not been shown in humans.

CIPROFLOXACIN (Cipro) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking capsicum with ciprofloxacin might increase levels and adverse effects of ciprofloxacin.  Details Animal research shows that concomitant use of capsaicin, the active constituent of capsicum, and ciprofloxacin increases the bioavailability of ciprofloxacin by up to 70% (22613).

THEOPHYLLINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking capsicum with theophylline might increase the levels and adverse effects of theophylline.  Details In animal research, oral administration of capsicum reduced excretion of theophylline (12405). However, capsicum does not seem to affect the pharmacokinetics of theophylline when administered intravenously (22616).

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AMINOGLYCOSIDE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Concomitant use of aminoglycoside antibiotics and magnesium can increase the risk for neuromuscular weakness.  Details Both aminoglycosides and magnesium reduce presynaptic acetylcholine release, which can lead to neuromuscular blockade and possible paralysis. This is most likely to occur with high doses of magnesium given intravenously (13362).

ANTACIDS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Use of acid reducers may reduce the laxative effect of magnesium oxide.  Details A retrospective analysis shows that, in the presence of H2 receptor antagonists (H2RAs) or proton pump inhibitors (PPIs), a higher dose of magnesium oxide is needed for a laxative effect (90033). This may also occur with antacids. Under acidic conditions, magnesium oxide is converted to magnesium chloride and then to magnesium bicarbonate, which has an osmotic laxative effect. By reducing acidity, antacids may reduce the conversion of magnesium oxide to the active bicarbonate salt.

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, magnesium may have antiplatelet effects, but the evidence is conflicting.  Details In vitro evidence shows that magnesium sulfate inhibits platelet aggregation, even at low concentrations (20304,20305). Some preliminary clinical evidence shows that infusion of magnesium sulfate increases bleeding time by 48% and reduces platelet activity (20306). However, other clinical research shows that magnesium does not affect platelet aggregation, although inhibition of platelet-dependent thrombosis can occur (60759).

BISPHOSPHONATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Magnesium can decrease absorption of bisphosphonates.  Details Cations, including magnesium, can decrease bisphosphonate absorption. Advise patients to separate doses of magnesium and these drugs by at least 2 hours (13363).

CALCIUM CHANNEL BLOCKERS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.  Details Magnesium inhibits calcium entry into smooth muscle cells and may therefore have additive effects with calcium channel blockers. Severe hypotension and neuromuscular blockades may occur when nifedipine is used with intravenous magnesium (3046,20264,20265,20266), although some contradictory evidence suggests that concurrent use of magnesium with nifedipine does not increase the risk of neuromuscular weakness (60831). High doses of magnesium could theoretically have additive effects with other calcium channel blockers.

DIGOXIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Magnesium salts may reduce absorption of digoxin.  Details Clinical evidence suggests that treatment with oral magnesium hydroxide or magnesium trisilicate reduces absorption of digoxin from the intestines (198,20268,20270). This may reduce the blood levels of digoxin and decrease its therapeutic effects.

GABAPENTIN (Neurontin) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Unlikely •  Level of Evidence = B Gabapentin absorption can be decreased by magnesium.  Details Clinical research shows that giving magnesium oxide orally along with gabapentin decreases the maximum plasma concentration of gabapentin by 33%, time to maximum concentration by 36%, and area under the curve by 43% (90032). Advise patients to take gabapentin at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

KETAMINE (Ketalar) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Magnesium might precipitate ketamine toxicity.  Details In one case report, a 62-year-old hospice patient with terminal cancer who had been stabilized on sublingual ketamine 150 mg four times daily experienced severe ketamine toxicity lasting for 2 hours after taking a maintenance dose of ketamine following an infusion of magnesium sulfate 2 grams (105078). Since both magnesium and ketamine block the NMDA receptor, magnesium is thought to have potentiated the effects of ketamine.

LEVODOPA/CARBIDOPA (Sinemet) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Magnesium can reduce the bioavailability of levodopa/carbidopa.  Details Clinical research in healthy volunteers shows that taking magnesium oxide 1000 mg with levodopa 100 mg/carbidopa 10 mg reduces the area under the curve (AUC) of levodopa by 35% and of carbidopa by 81%. In vitro and animal research shows that magnesium produces an alkaline environment in the digestive tract, which might lead to degradation and reduced bioavailability of levodopa/carbidopa (100265).

POTASSIUM-SPARING DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Potassium-sparing diuretics decrease excretion of magnesium, possibly increasing magnesium levels.  Details Potassium-sparing diuretics also have magnesium-sparing properties, which can counteract the magnesium losses associated with loop and thiazide diuretics (9613,9614,9622). Theoretically, increased magnesium levels could result from concomitant use of potassium-sparing diuretics and magnesium supplements.

QUINOLONE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Magnesium decreases absorption of quinolones.  Details Magnesium can form insoluble complexes with quinolones and decrease their absorption (3046). Advise patients to take these drugs at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

SEVELAMER (Renagel, Renvela) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Sevelamer may increase serum magnesium levels.  Details In patients on hemodialysis, sevelamer use was associated with a 0.28 mg/dL increase in serum magnesium. The mechanism of this interaction remains unclear (96486).

SKELETAL MUSCLE RELAXANTS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = A Parenteral magnesium alters the pharmacokinetics of skeletal muscle relaxants, increasing their effects and accelerating the onset of effect.  Details Parenteral magnesium shortens the time to onset of skeletal muscle relaxants by about 1 minute and prolongs the duration of action by about 2 minutes. Magnesium potentiates the effects of skeletal muscle relaxants by decreasing calcium-mediated release of acetylcholine from presynaptic nerve terminals, reducing postsynaptic sensitivity to acetylcholine, and having a direct effect on the membrane potential of myocytes (3046,97492,107364). Magnesium also has vasodilatory actions and increases cardiac output, allowing a greater amount of muscle relaxant to reach the motor end plate (107364). A clinical study found that low-dose rocuronium (0.45 mg/kg), when given after administration of magnesium 30 mg/kg over 10 minutes, has an accelerated onset of effect, which matches the onset of effect seen with a full-dose rocuronium regimen (0.6 mg/kg) (96485). In another clinical study, onset times for rocuronium doses of 0.3, 0.6, and 1.2 mg/kg were 86, 76, and 50 seconds, respectively, when given alone, but were reduced to 66, 44, and 38 seconds, respectively, when the doses were given after a 15-minute infusion of magnesium sulfate 60 mg/kg (107364). Giving intraoperative intravenous magnesium sulfate, 50 mg/kg loading dose followed by 15 mg/kg/hour, reduces the onset time of rocuronium, enhances its clinical effects, reduces the dose of intraoperative opiates, and prolongs the spontaneous recovery time (112781,112782). It does not affect the activity of subsequently administered neostigmine (112782).

SULFONYLUREAS Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Magnesium increases the systemic absorption of sulfonylureas, increasing their effects and side effects.  Details Clinical research shows that administration of magnesium hydroxide with glyburide increases glyburide absorption, increases maximal insulin response by 35-fold, and increases the risk of hypoglycemia, when compared with glyburide alone (20307). A similar interaction occurs between magnesium hydroxide and glipizide (20308). The mechanism of this effect appears to be related to the elevation of gastrointestinal pH by magnesium-based antacids, increasing solubility and enhancing absorption of sulfonylureas (22364).

TETRACYCLINE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Magnesium decreases absorption of tetracyclines.  Details Magnesium can form insoluble complexes with tetracyclines in the gut and decrease their absorption and antibacterial activity (12586). Advise patients to take these drugs 1 hour before or 2 hours after magnesium supplements.

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General ...Orally, large doses of betony might cause significant gastrointestinal irritation due to the tannin component (5,6).

Gastrointestinal ...Orally, large doses of betony might cause significant gastrointestinal irritation due to the tannin component. Betony contains about 15% tannins (5,6).

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General ...Orally, black cohosh is generally well tolerated when used in typical doses.
Most Common Adverse Effects:
Orally: Breast tenderness, dizziness, gastrointestinal upset, headache, irritability, rash, tiredness.
Serious Adverse Effects (Rare):
Orally: Endometrial hyperplasia and hepatotoxicity, although data are conflicting for both.

Cardiovascular ...A single case of reversible bradycardia has been reported for a 59-year-old female who took one tablet of a specific black cohosh product (Remifemin, Schaper & Brümmer) daily for 2 weeks. The adverse event was considered probably related to black cohosh use, although the exact mechanism by which black cohosh exerted this effect was unclear (35920).
There has been concern that, if black cohosh has estrogen-like effects, it could also potentially cause estrogen-like side effects including increased risk for thromboembolism and cardiovascular disease. These outcomes have not been specifically assessed in long-term trials; however, some research shows that a specific black cohosh extract (CimiPure, PureWorld) does not significantly affect surrogate markers for thromboembolism and cardiovascular risk such as fibrinogen, cholesterol, triglycerides, glucose, or insulin levels compared to placebo (16850).

Dermatologic ...Black cohosh has been associated with skin irritation and rashes (7054,10987,14330,15889,35853). A case report describes a patient who developed cutaneous pseudolymphoma 6 months after starting a specific black cohosh extract (Remifemin). Symptoms resolved within 12 weeks of discontinuing black cohosh (15890).

Gastrointestinal ...Orally, black cohosh can commonly cause gastrointestinal upset (4383,4615,4616,10988,13184,35824,35853,35965,103269,111714). Constipation and indigestion have also been reported (7054,35852).

Genitourinary ...Orally, black cohosh, including the specific black cohosh product Remifemin, may cause vaginal bleeding and breast tenderness in some postmenopausal patients (15889,35824). However, the frequency of these events seems to be less than that of tibolone, a prescription hormone medication used to treat symptoms of menopause (15889,35904).
Due to the potential estrogen-like effects, there is concern that black cohosh might increase the risk of endometrial hyperplasia. However, a specific black cohosh extract CR BNO 1055 (Klimadynon/Menofem, Bionorica AG) does not appear to cause endometrial hyperplasia. Clinical research in postmenopausal adults shows that taking 40 mg daily of this extract for 12 weeks does not significantly increase superficial cells when compared with placebo, and causes significantly fewer superficial cells when compared with conjugated estrogens (Premarin) (14330). Additional clinical research shows that taking 40 mg daily of this extract for a year does not increase the risk of endometrial hyperplasia or endometrial thickening in postmenopausal adults (15036). Another specific combination product containing black cohosh extract plus St. John's wort (Gynoplus, Jin-Yang Pharm) also does not significantly increase superficial cells compared to placebo after 12 weeks of treatment (15893). Some patients taking tamoxifen plus black cohosh have experienced endometrial hyperplasia and vaginal bleeding. However, these effects are more likely due to tamoxifen than black cohosh (7054).

Hepatic ...There is concern that black cohosh might cause liver disease, hepatotoxicity, or hepatitis. Adverse effects on the liver have not been documented in clinical studies. However, multiple case reports of liver toxicity, hepatitis, and abnormal liver function have been described in females taking black cohosh products alone or in combination with other herbs or drugs. In some cases, patients developed liver failure and required immediate liver transplantation (4383,10692,11909,12006,13144,14469,15160,16721,16722,16723) (16724,16727,35883,35888,35890,35895,89465,101592,107906). In one case, a female developed autoimmune hepatitis after 3 weeks of taking black cohosh. Symptoms resolved 2 weeks after discontinuing black cohosh (11906). In at least three cases, females have developed elevated liver enzymes and symptoms of hepatotoxicity after taking black cohosh products. Symptoms resolved and liver enzymes normalized within a week of discontinuing black cohosh (16725,16726). Analysis of two liver biopsies suggests that hepatotoxicity associated with black cohosh use results from the accumulation of 4HNE protein adducts in the cytoplasm of liver cells, which promotes the migration of lymphocytes to the affected area and induces an autoimmune response leading to troxis necrosis (89469).
However, many of these cases are poorly documented. Causality is possible based on some reports; however, other reports do not indicate that black cohosh is the probable cause of the events (15891,15892,16722,16723,16727,89465). Hepatitis can occur with no identifiable cause, raising the possibility that black cohosh and hepatitis might have been coincidental in some cases. Also, plant misidentification can occur, resulting in accidental substitution of a hepatotoxic plant (11910). Therefore, some experts argue that these cases do not provide conclusive evidence that black cohosh is responsible for liver disease (17085,35882,111634). Nonetheless, some countries require cautionary labeling on black cohosh products suggesting a risk of liver toxicity. The United States Pharmacopeia also recommends cautionary labeling on black cohosh products (16722). Until more is known about this potential risk, consider monitoring liver function in patients who take black cohosh.

Musculoskeletal ...One patient treated with black cohosh in a clinical trial discontinued treatment due to edema and arthralgia (35897).
Black cohosh has been linked to asthenia and muscle damage in one case. A 54-year-old female experienced asthenia with elevated creatinine phosphokinase (CPK) and lactate dehydrogenase (LDH) levels while taking black cohosh. The patient had taken a specific black cohosh extract (Remifemin) for 1 year, discontinued it for 2 months, restarted it, and then experienced symptoms 2 months later. Symptoms began to resolve 10 days after discontinuing black cohosh (14299).

Neurologic/CNS ...Orally, black cohosh may cause headache, dizziness, or tiredness (35852,35886). There is one case report of seizures in a female who used black cohosh, evening primrose oil, and chasteberry (10988).
Also, there has been a case report of severe complications, including seizures, renal failure, and respiratory distress, in an infant whose mother was given an unknown dose of black cohosh and blue cohosh at 42 weeks gestation to induce labor (1122,9492,9493). However, this adverse effect may have been attributable to blue cohosh.
In another case report, orobuccolingual dyskinesia, including tongue-biting, eating difficulties, and speech problems, was reported in a 46-year-old female who took two tablets containing black cohosh 20 mg and Panax ginseng 50 mg daily for 15 months. The patient's condition improved after stopping treatment with the herbs and taking clonazepam 2 mg daily with baclofen 40 mg daily (89735).

Ocular/Otic ...There is some concern that black cohosh might increase the risk of retinal vein thrombosis due to its estrogenic activity. In one case, a patient with protein S deficiency and systemic lupus erythematosus (SLE) experienced retinal vein thrombosis 3 days after taking a combination product containing black cohosh 250 mg, red clover 250 mg, dong quai 100 mg, and wild yam 276 mg (13155). It is unclear if this event was due to black cohosh, other ingredients, the combination, or another factor.

Oncologic ...There is some concern that black cohosh may affect hormone-sensitive cancers, such as some types of breast or uterine cancer, due to its potential estrogenic effects. However, evidence from a cohort study suggests that regular use of black cohosh is not associated with the risk of breast or endometrial cancer (17412,111634).

Psychiatric ...A 36-year-old female with a 15-year history of depression developed mania with psychotic and mixed features after taking a black cohosh extract 40 mg daily. The patient gradually recovered after stopping black cohosh and receiving treatment with antipsychotics (104517).

Pulmonary/Respiratory ...There has been a case report of severe complications, including seizures, renal failure, and respiratory distress, in an infant whose mother was given an unknown dose of black cohosh and blue cohosh at 42 weeks gestation to induce labor (1122,9492,9493). However, this adverse effect may have been attributable to blue cohosh.

Renal ...There has been a case report of severe complications, including seizures, renal failure, and respiratory distress, in an infant whose mother was given an unknown dose of black cohosh and blue cohosh at 42 weeks gestation to induce labor (1122,9492,9493). However, this adverse effect may have been attributable to blue cohosh.

Other ...While rare, weight gain has been reported in some patients taking black cohosh. However, in most cases the causality could not be established. A review of the literature, including published case reports, spontaneous reports to adverse event databases, and clinical trials, suggests that black cohosh does not cause weight gain (107907).

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General ...Orally, capsicum is generally well tolerated in amounts typically found in food or when the extract is used in doses of up to 200 mg daily. Topically and intranasally, capsaicin, a constituent of capsicum, is generally well tolerated.
Most Common Adverse Effects:
Orally: Belching, bloating, burning, diarrhea, dyspepsia, gas, headache, mild constipation, nausea, rhinorrhea, skin flushing, and sweating.
Serious Adverse Effects (Rare):
Orally: Cases of myocardial infarction and hypertensive crisis have been reported.

Cardiovascular ...Orally, palpitation was reported in one clinical trial (105196).
One case of myocardial infarction has been reported in a 41-year-old male without cardiovascular risk factors; the event was attributed to the use of an oral capsicum pepper pill that the patient had been taking for weight loss (40768). Another case of coronary vasospasm and acute myocardial infarction has been reported for a healthy 29-year-old male; the event was attributed to the use of a topical capsicum-containing patch that the patient had been applying to the middle of the back for 6 days (40658). Two cases of arterial hypertensive crisis have been reported for individuals who ingested a large amount of peppers and chili peppers the day before. One of the patients also had an acute myocardial infarction, and the other had high levels of thyroid stimulating hormone (40569,40606).

Dermatologic ...Orally, capsicum or its constituent capsaicin may cause urticaria and skin wheals in rare cases (96457,105203).
Topically, capsicum can cause a prickling sensation, itching, pain, burning, edema, stinging, irritation, rash, and erythema. About 1 in 10 patients who use capsaicin topically discontinue treatment because of adverse effects. These effects seem to occur more often with topical formulations containing higher concentrations of capsaicin, the active constituent of capsicum. Side effects tend to diminish with continued use (12401,15260,15261,40358,40439,40483,40547,40676,40682,40719)(40784,40847,92979,92983,92984,96453,105193,105197,105202,111514). In one case, application of a capsaicin 8% patch (Qutenza) for 60 minutes caused a second-degree burn, characterized by burning, erythema, severe pain, and blistering at the administration site. The burn was treated with topical corticosteroids, but 9 months later neuropathic pain persisted, resulting in limited mobility. It is unclear whether the mobility sequalae were caused by topical capsaicin or the patient's pre-existing neurological disorders (111514). Skin contact with fresh capsicum fruit can also cause irritation or contact dermatitis (12408).
Intranasally, capsaicin can cause nasal burning and pain in most patients. It also often causes lacrimation, sneezing, and excessive nasal secretion; however, these side effects appear to diminish with repeat applications (14323,14329,14358). In some cases, the burning sensation disappears after 5-8 applications (14351,14358). In some cases, patients are pretreated with intranasal lidocaine to decrease the pain of intranasal capsaicin treatment. However, even with lidocaine pretreatment, patients seem to experience significant pain (14324).

Gastrointestinal ...Orally, capsicum can cause upper abdominal discomfort, including irritation, fullness, dyspepsia, gas, bloating, nausea, epigastric pain and burning, anal burning, diarrhea, mild constipation, and belching (12403,12410,40338,40427,40456,40503,40560,40584,40605,40665)(40718,40725,40745,40808,40828,96456,96457,105194,105196). There is a case report of a 3-year-old female who experienced a burning and swollen mouth and lips after touching the arm of a parent that had been treated with a capsaicin patch and then placing the fingers in the mouth (105199). Excessive amounts of capsaicin can lead to gastroenteritis and hepatic necrosis (12404). In a case report, a 40-year-old male with diabetes consumed white wine daily and chewed cayenne which was thought to result in black teeth stains and loss of enamel (40809). Some preliminary research links ingestion of capsaicin with stomach and gallbladder cancer; however the link may be due to contamination of capsaicin products with carcinogens (40771).
Topically, capsaicin can cause diarrhea and vomiting (105202).

Immunologic ...In a case report, a 34-year-old female had anaphylaxis involving difficulty breathing and stupor and also urticaria after consuming a red bell pepper, which is in the capsicum genus. The causal chemical was theorized to be 1,3-beta-glucanase (92978). In another case report, a 33-year-old female experienced angioedema, difficulty breathing and swallowing, and urticaria after ingesting raw green and red peppers (92982).

Neurologic/CNS ...Orally, capsicum can cause sweating and flushing of the head and neck, lacrimation, headache, faintness, and rhinorrhea (7005,12410,105196,105203). Topically, applying capsaicin can cause headache (96450,105202). Injection of capsaicin into the intermetatarsal space has also been associated with headache (96454).

Ocular/Otic ...Topically, capsicum can be extremely irritating to the eyes and mucous membranes. Capsicum oleoresin, an oily extract in pepper self-defense sprays, causes intense eye pain. It can also cause erythema, blepharospasm, tearing, shortness of breath, and blurred vision. In rare cases, corneal abrasions have occurred (12408,12409,40345,40348,40383,40720,40857).
Inhalation of capsicum can cause eye irritation, and allergic alveolitis (5885). In a case report, a 38-year-old female had acute anterior uveitis that developed about 12 hours after using a specific patch (Isola Capsicum N Plus) that contained capsaicin 1.5 mg per patch and methyl salicylate 132 mg per patch for neck pain. The uveitis was controlled with topical steroids and did not recur (92977).

Oncologic ...Population research suggests that moderate to high intake of capsaicin, the active constituent of capsicum, is associated with an increased risk of gastric cancer, while low intake is associated with a decreased risk. It is not clear from the study what amount of capsaicin is considered high versus low intake (92988). Additionally, some research suggests that any link may be due to contamination of capsaicin products with carcinogens (40771).

Pulmonary/Respiratory ...Orally, difficulty breathing was reported in a clinical trial (105196).
Topically, nasopharyngitis related to the use of a cream containing capsaicin has been reported (105202).
Inhalation of capsicum and exposure to capsicum oleoresin spray can cause cough, dyspnea, pain in the nasal passages, sneezing, rhinitis, and nasal congestion (5885,15016,40522,40546,40647). In rare cases, inhalation of the capsicum oleoresin or pepper spray has caused cyanosis, apnea, respiratory arrest and death in people. Death was caused by asphyxiation probably due to acute laryngeal edema and bronchoconstriction from inhalation of the capsicum oleoresin spray (40546,40672,40837,40879).
In a case report, a 47-year-old female who was exposed to capsaicin gas for more than 20 minutes experienced acute cough, shortness of breath, short-term chest pain, wheezing, and difficulty breathing for months afterwards (92980). In rare cases, exposure to capsicum oleoresin spray resulted in apnea, pulmonary injury, cyanosis, and even respiratory arrest (40383,40546).

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General ...No adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted.

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General ...Magnesium is generally well tolerated. Some clinical research shows no differences in adverse effects between placebo and magnesium groups.
Most Common Adverse Effects:
Orally: Diarrhea, gastrointestinal irritation, nausea, and vomiting.
Intravenously: Bradycardia, dizziness, flushing sensation, hypotension, and localized pain and irritation. In pregnancy, may cause blurry vision, dizziness, lethargy, nausea, nystagmus, and perception of warmth.
Serious Adverse Effects (Rare):
All ROAs: With toxic doses, loss of reflexes and respiratory depression can occur. High doses in pregnancy can increase risk of neonatal mortality and neurological defects.

Cardiovascular ...Intravenously, magnesium can cause bradycardia, tachycardia, and hypotension (13356,60795,60838,60872,60960,60973,60982,61001,61031,114681). Inhaled magnesium administered by nebulizer may also cause hypotension (113466). Magnesium sulfate may cause rapid heartbeat when administered antenatally (60915,114681).
In one case report, a 99-year-old male who took oral magnesium oxide 3000 mg daily for chronic constipation was hospitalized with hypermagnesemia, hypotension, bradycardia, heart failure, cardiomegaly, second-degree sinoatrial block, and complete bundle branch block. The patient recovered after discontinuing the magnesium oxide (108966).

Dermatologic ...Intravenously, magnesium may cause flushing, sweating, and problems at the injection site (including burning pain) (60960,60982,111696,114681). In a case study, two patients who received intravenous magnesium sulfate for suppression of preterm labor developed a rapid and sudden onset of an urticarial eruption (a skin eruption of itching welts). The eruption cleared when magnesium sulfate was discontinued (61045). Orally, magnesium oxide may cause allergic skin rash, but this is rare. In one case report, a patient developed a rash after taking 600 mg magnesium oxide (Maglax) (98291).

Gastrointestinal ...Orally, magnesium can cause gastrointestinal irritation, nausea, vomiting, and diarrhea (1194,4891,10661,10663,18111,60951,61016,98290). In rare cases, taking magnesium orally might cause a bezoar, an indigestible mass of material which gets lodged in the gastrointestinal tract. In a case report, a 75-year-old female with advanced rectal cancer taking magnesium 1500 mg daily presented with nausea and anorexia from magnesium oxide bezoars in her stomach (99314). Magnesium can cause nausea, vomiting, or dry mouth when administered intravenously or by nebulization (60818,60960,60982,104400,113466,114681). Antenatal magnesium sulfate may also cause nausea and vomiting (60915,114681). Two case reports suggest that giving magnesium 50 grams orally for bowel preparation for colonoscopy in patients with colorectal cancer may lead to intestinal perforation and possibly death (90006).
Delayed meconium passage and obstruction have been reported rarely in neonates after intravenous magnesium sulfate was given to the mother during pregnancy (60818). In a retrospective study of 200 neonates born prematurely before 32 weeks of gestation, administration of prenatal IV magnesium sulfate, as a 4-gram loading dose and then 1-2 grams hourly, was not associated with the rate of meconium bowel obstruction when compared with neonates whose mothers had not received magnesium sulfate (108728).

Genitourinary ...Intravenously, magnesium sulfate may cause renal toxicity or acute urinary retention, although these events are rare (60818,61012). A case of slowed cervical dilation at delivery has been reported for a patient administered intravenous magnesium sulfate for eclampsia (12592). Intravenous magnesium might also cause solute diuresis. In a case report, a pregnant patient experienced polyuria and diuresis after having received intravenous magnesium sulfate in Ringer's lactate solution for preterm uterine contractions (98284).

Hematologic ...Intravenously, magnesium may cause increased blood loss at delivery when administered for eclampsia or pre-eclampsia (12592). However, research on the effect of intravenous magnesium on postpartum hemorrhage is mixed. Some research shows that it does not affect risk of postpartum hemorrhage (60982), while other research shows that intrapartum magnesium administration is associated with increased odds of postpartum hemorrhage, increased odds of uterine atony (a condition that increases the risk for postpartum hemorrhage) and increased need for red blood cell transfusions (97489).

Musculoskeletal ...Intravenously, magnesium may cause decreased skeletal muscle tone, muscle weakness, or hypocalcemic tetany (60818,60960,60973).
Although magnesium is important for normal bone structure and maintenance (272), there is concern that very high doses of magnesium may be detrimental. In a case series of 9 patients receiving long-term tocolysis for 11-97 days, resulting in cumulative magnesium sulfate doses of 168-3756 grams, a lower bone mass was noted in 4 cases receiving doses above 1000 grams. There was one case of pregnancy- and lactation-associated osteoporosis and one fracture (108731). The validity and clinical significance of this data is unclear.

Neurologic/CNS ...Intravenously, magnesium may cause slurred speech, dizziness, drowsiness, confusion, or headaches (60818,60960,114681). With toxic doses, loss of reflexes, neurological defects, drowsiness, confusion, and coma can occur (8095,12589,12590).
A case report describes cerebral cortical and subcortical edema consistent with posterior reversible encephalopathy syndrome (PRES), eclampsia, somnolence, seizures, absent deep tendon reflexes, hard to control hypertension, acute renal failure and hypermagnesemia (serum level 11.5 mg/dL), after treatment with intravenous magnesium sulfate for preeclampsia in a 24-year-old primigravida at 39 weeks gestation with a previously uncomplicated pregnancy. The symptoms resolved after 4 days of symptomatic treatment in an intensive care unit, and emergency cesarian delivery of a healthy infant (112785).

Ocular/Otic ...Intravenously, magnesium may cause blurred vision (114681). Additionally, cases of visual impairment or nystagmus have been reported following magnesium supplementation, but these events are rare (18111,60818).

Psychiatric ...A case of delirium due to hypermagnesemia has been reported for a patient receiving intravenous magnesium sulfate for pre-eclampsia (60780).

Pulmonary/Respiratory ...Intravenously, magnesium may cause respiratory depression and tachypnea when used in toxic doses (12589,61028,61180).

Other ...Hypothermia from magnesium used as a tocolytic has been reported (60818).

(Read more about MAGNESIUM)