Below is general information about the effectiveness of the known ingredients contained in the product Green Tea Herbal Slimming Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
Below is general information about the safety of the known ingredients contained in the product Green Tea Herbal Slimming Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
LIKELY SAFE ...when green tea is consumed as a beverage in moderate amounts (733,6031,9222,9223,9225,9226,9227,9228,14136,90156)(90159,90168,90174,90184,95696). Green tea contains caffeine. According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, drinking up to 8 cups of green tea daily, or approximately 400 mg of caffeine, is not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806). ...when green tea extract cream or ointment is used topically and appropriately, short-term. A green tea extract 3% cream, applied twice daily, has been used with apparent safety for up to 8 weeks, and a specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins has been safely used for up to 16 weeks (15067). The safety of treatment for longer durations or multiple treatment courses is not known.
POSSIBLY SAFE ...when green tea extract is used orally. Green tea extract containing 7% to 12% caffeine has been used safely for up to 2 years (8117,37725). Also decaffeinated green tea extract up to 1.3 grams daily enriched in EGCG has been used safely for up to 12 months (90158,97131). In addition, green tea extract has been safely used as part of an herbal mixture also containing garcinia, coffee, and banaba extracts for 12 weeks (90137). ...when used topically and appropriately as a cream or mouthwash (6065,11310,90141,90150,90151).
POSSIBLY UNSAFE ...when consumed as a beverage in large quantities. Green tea contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, psychological dependence, and other significant adverse effects. Doses of caffeine greater than 600 mg per day, or approximately 12 cups of green tea, have been associated with significant adverse effects such as tachyarrhythmias and sleep disturbances (11832). These effects would not be expected to occur with the consumption of decaffeinated green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. There is also some speculation that green tea products containing higher amounts of the catechin epigallocatechin gallate (EGCG) might have increased risk of adverse events. Some research has found that taking green tea products containing EGCG levels greater than 200 mg is associated with increased risk of mild adverse effects such as constipation, increased blood pressure, and rash (90161). Other research has found that doses of EGCG equal to or above 800 mg daily may be associated with increased risk of liver injury in humans (95440,95696,97131).
LIKELY UNSAFE ...when used orally in very high doses. The fatal acute oral dose of caffeine is estimated to be 10-14 grams (150-200 mg per kilogram). Serious toxicity can occur at lower doses depending on variables in caffeine sensitivity such as smoking, age, and prior caffeine use (11832).
CHILDREN: POSSIBLY SAFE
when used orally by children and adolescents in amounts commonly found in foods and beverages (4912,11833).
Intake of caffeine in doses of less than 2.5 mg/kg daily is not associated with significant adverse effects in children and adolescents (11733,98806). ...when used for gargling three times daily for up to 90 days (90150).
There is insufficient reliable information available about the safety of green tea extract when used orally in children. However, taking green tea extract orally has been associated with potentially serious, albeit uncommon and unpredictable cases, of hepatotoxicity in adults. Therefore, some experts recommend that children under the age of 18 years of age do not use products containing green tea extract (94897).
PREGNANCY: POSSIBLY SAFE
when used orally in moderate amounts.
Due to the caffeine content of green tea, pregnant patients should closely monitor their intake to ensure moderate consumption. Fetal blood concentrations of caffeine approximate maternal concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,11733,16014,16015,98806). In some studies consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage (16014). This increased risk may be most likely to occur in those with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, most healthy pregnant patients can safely consume doses up to 300 mg daily without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). Advise keeping caffeine consumption below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. Based on animal models, green tea extract catechins are also transferred to the fetus, but in amounts 50-100 times less than maternal concentrations (15010). The potential impact of these catechins on the human fetus is not known, but animal models suggest that the catechins are not teratogenic (15011).
PREGNANCY: POSSIBLY UNSAFE
when used orally in amounts providing more than 300 mg caffeine daily.
Caffeine from green tea crosses the placenta, producing fetal blood concentrations similar to maternal levels (4260). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise keeping caffeine consumption from all sources below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. High maternal doses of caffeine throughout pregnancy have also resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711). However, some research has also found that intrauterine exposure to even modest amounts of caffeine, based on maternal blood levels during the first trimester, is associated with a shorter stature in children ages 4-8 years (109846). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.
There is also concern that consuming large amounts of green tea might have antifolate activity and potentially increase the risk of folic acid deficiency-related birth defects. Catechins in green tea inhibit the enzyme dihydrofolate reductase in vitro (15012). This enzyme is responsible for converting folic acid to its active form. Preliminary evidence suggests that increasing maternal green tea consumption is associated with increased risk of spina bifida (15068). Also, evidence from epidemiological research suggests that serum folate levels in pregnant patients with high green tea intake (57.3 mL per 1000 kcal) are decreased compared to participants who consume moderate or low amounts of green tea (90171). More evidence is needed to determine the safety of using green tea during pregnancy. For now, advise pregnant patients to avoid consuming large quantities of green tea.
LACTATION: POSSIBLY SAFE
when used orally in moderate amounts.
Due to the caffeine content of green tea, nursing parents should closely monitor caffeine intake. Breast milk concentrations of caffeine are thought to be approximately 50% of maternal serum concentrations (9892).
LACTATION: POSSIBLY UNSAFE
when used orally in large amounts.
Consumption of green tea might cause irritability and increased bowel activity in nursing infants (6026). There is insufficient reliable information available about the safety of green tea extracts when applied topically during breast-feeding.
LIKELY SAFE ...when used orally in amounts commonly found in foods. Licorice has Generally Recognized as Safe (GRAS) status in the US (4912).
POSSIBLY SAFE ...when licorice products that do not contain glycyrrhizin (deglycyrrhizinated licorice) are used orally and appropriately for medicinal purposes. Licorice flavonoid oil 300 mg daily for 16 weeks, and deglycyrrhizinated licorice products in doses of up to 4.5 grams daily for up to 16 weeks, have been used with apparent safety (6196,11312,11313,17727,100984,102960). ...when licorice products containing glycyrrhizin are used orally in low doses, short-term. Licorice extract 272 mg, containing glycyrrhizin 24.3 mg, has been used daily with apparent safety for 6 months (102961). A licorice extract 1000 mg, containing monoammonium glycyrrhizinate 240 mg, has been used daily with apparent safety for 12 weeks (110320). In addition, a syrup providing licorice extract 750 mg has been used twice daily with apparent safety for 5 days (104558). ...when applied topically. A gel containing 2% licorice root extract has been applied to the skin with apparent safety for up to 2 weeks. (59732). A mouth rinse containing 5% licorice extract has been used with apparent safety four times daily for up to one week (104564).
POSSIBLY UNSAFE ...when licorice products containing glycyrrhizin are used orally in large amounts for several weeks, or in smaller amounts for longer periods of time. The European Scientific Committee on Food recommends that a safe average daily intake of glycyrrhizin should not exceed 10 mg (108577). In otherwise healthy people, consuming glycyrrhizin daily for several weeks or longer can cause severe adverse effects including pseudohyperaldosteronism, hypertensive crisis, hypokalemia, cardiac arrhythmias, and cardiac arrest. Doses of 20 grams or more of licorice products, containing at least 400 mg glycyrrhizin, are more likely to cause these effects; however, smaller amounts have also caused hypokalemia and associated symptoms when taken for months to years (781,3252,15590,15592,15594,15596,15597,15599,15600,16058)(59731,59740,59752,59785,59786,59787,59792,59795,59805,59811)(59816,59818,59820,59822,59826,59828,59849,59850,59851,59867)(59882,59885,59888,59889,59895,59900,59906,97213,110305). In patients with hypertension, cardiovascular or kidney conditions, or a high salt intake, as little as 5 grams of licorice product or 100 mg glycyrrhizin daily can cause severe adverse effects (15589,15593,15598,15600,59726).
PREGNANCY: UNSAFE
when used orally.
Licorice has abortifacient, estrogenic, and steroid effects. It can also cause uterine stimulation. Heavy consumption of licorice, equivalent to 500 mg of glycyrrhizin per week (about 250 grams of licorice per week), during pregnancy seems to increase the risk of delivery before gestational age of 38 weeks (7619,10618). Furthermore, high intake of glycyrrhizin, at least 500 mg per week, during pregnancy is associated with increased salivary cortisol levels in the child by the age of 8 years. This suggests that high intake of licorice during pregnancy may increase hypothalamic-pituitary-adrenocortical axis activity in the child (26434); avoid using.
LACTATION:
Insufficient reliable information available; avoid using.
LIKELY SAFE ...when used orally and appropriately, short-term. Senna is an FDA-approved nonprescription drug (8424,15429,15431,15442,40086,40088,74535,74545,74548,74562)(74567,74570,74583,74585,74586,74587,74593,74603,74606,74607)(74609,74613,74615,74624,74636,74639,74644,74650,74653,92711)(92712).
POSSIBLY UNSAFE ...when used orally long-term or in high doses. Long-term, frequent use, or use of high doses has been linked to serious side effects including laxative dependence and liver toxicity (13057,13095).
CHILDREN: LIKELY SAFE
when used orally and appropriately, short-term.
Senna is an FDA-approved nonprescription drug for use in children 2 years and older. (15429,15434,15435).
CHILDREN: POSSIBLY UNSAFE
when used orally long-term or in high doses.
Long-term, frequent use, or use of high doses has been linked to serious side effects including laxative dependence and liver toxicity (13057,13095,105956).
PREGNANCY: POSSIBLY SAFE
when used orally and appropriately, short-term (15429,24480).
POSSIBLY UNSAFE...when used orally long-term or in high doses. Long-term, frequent use, or use of high doses has been linked to serious side effects including laxative dependence and liver toxicity (13057,13095).
LACTATION: POSSIBLY SAFE
when used orally and appropriately, short term.
Although small amounts of constituents of senna cross into breast milk, senna has been taken while breast-feeding with apparent safety. Senna does not cause changes in the frequency or consistency of infants' stools. (6026,15429,15436,15437,24482,24484,24485,24486,24487,74545).
Below is general information about the interactions of the known ingredients contained in the product Green Tea Herbal Slimming Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
Theoretically, high doses of green tea might increase the effects and side effects of 5-fluorouracil.
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Animal research shows that taking green tea in amounts equivalent to about 6 cups daily in humans for 4 weeks prior to receiving a single injection of 5-fluorouracil increases the maximum plasma levels of 5-fluorouracil by about 2.5-fold and the area under the curve by 425% (98424).
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Theoretically, green tea might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
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Green tea contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine doesn't seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine (11771). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).
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Theoretically, alcohol might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Concomitant use of alcohol and caffeine can increase caffeine serum concentrations and the risk of caffeine adverse effects. Alcohol reduces caffeine metabolism (6370).
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Theoretically, green tea may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
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Conflicting reports exist regarding the effect of green tea on bleeding risk when used with anticoagulant or antiplatelet drugs; however, most evidence suggests that drinking green tea in moderate amounts is unlikely to cause a significant interaction. Green tea contains small amounts of vitamin K, approximately 7 mcg per cup (100524). Some case reports have associated the antagonism of warfarin with the vitamin K content of green tea (1460,1461,1463,4211,6048,8028,20868). However, these reports are rare, and very large doses of green tea (about 8-16 cups daily) appear to be needed to cause these effects. Furthermore, the catechins and caffeine in green tea are reported to have antiplatelet activity (733,8028,8029,12882,100524).
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Theoretically, taking green tea with antidiabetes drugs might interfere with blood glucose control.
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Green tea extract seems to reduce the levels and clinical effects of atorvastatin.
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In healthy humans, taking green tea extract 300 mg or 600 mg along with atorvastatin reduces plasma levels of atorvastatin by approximately 24%. The elimination of atorvastatin is not affected (102714). Atorvastatin is a substrate of organic anion-transporting polypeptides (OATPs). Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs. Some OATPs are expressed in the small intestine and are responsible for the uptake of drugs and other compounds, which may have resulted in reduced plasma levels of atorvastatin (19079). It is not clear if drinking green tea alters the absorption of atorvastatin.
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Green tea contains caffeine. Theoretically, concomitant use of large amounts of caffeine might increase cardiac inotropic effects of beta-agonists (15).
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Theoretically, green tea might interfere with the effects of bortezomib.
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In vitro research shows that green tea polyphenols, such as epigallocatechin gallate (EGCG), interact with bortezomib and block its proteasome inhibitory action. This prevents the induction of cell death in multiple myeloma or glioblastoma cancer cell lines (17212). Advise patients taking bortezomib, not to take green tea.
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Theoretically, green tea might reduce the effects of carbamazepine and increase the risk for convulsions.
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Green tea contains caffeine. Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when taken in doses above 400 mg/kg (23559,23561). Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine 2-fold in healthy individuals (23562).
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Theoretically, green tea might reduce the levels and clinical effects of celiprolol.
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In a small human study, taking green tea daily for 4 days appears to decrease blood and urine levels of celiprolol by at least 98% (104607). This interaction is possibly due to the inhibition of organic anion transporting polypeptide (OATP). Green tea catechins have been shown to inhibit organic anion transporting polypeptides (OATP), one of which, OATP1A2, is found in the intestine (19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).
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Theoretically, concomitant use might increase the effects and adverse effects of caffeine in green tea.
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Green tea contains caffeine. Cimetidine can reduce caffeine clearance by 31% to 42% (11736).
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Theoretically, green tea might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
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Animal research suggests that, although green tea extract does not affect the elimination of clozapine, it delays the time to reach peak concentration and reduces the peak plasma levels (90173). Also, concomitant administration of green tea and clozapine might theoretically cause acute exacerbation of psychotic symptoms due to the caffeine in green tea. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg daily inhibit clozapine metabolism (5051). Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Researchers speculate that caffeine might inhibit CYP1A2. However, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients be more sensitive to the interaction between clozapine and caffeine (13741).
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Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in green tea.
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Green tea contains caffeine. Oral contraceptives can decrease caffeine clearance by 40% to 65% (8644).
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Theoretically, concomitant use might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Caffeine is metabolized by cytochrome P450 1A2 (CYP1A2) (3941,5051,11741,23557,23573,23580,24958,24959,24960,24962), (24964,24965,24967,24968,24969,24971,38081,48603). Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from green tea and increase caffeine levels.
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Green tea is unlikely to produce clinically significant changes in the levels and clinical effects of CYP3A4 substrates.
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Theoretically, green tea might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
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Green tea contains caffeine. Caffeine might inhibit dipyridamole-induced vasodilation (11770,11772). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).
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Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
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In human research, disulfiram decreases the clearance and increases the half-life of caffeine (11840).
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Theoretically, using green tea with diuretic drugs might increase the risk of hypokalemia.
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Theoretically, concomitant use might increase the risk for stimulant adverse effects.
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Theoretically, estrogens might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Estrogen inhibits caffeine metabolism (2714).
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Theoretically, green tea might reduce the effects of ethosuximide and increase the risk for convulsions.
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Green tea contains caffeine. Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide (23560). However, this effect has not been reported in humans.
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Theoretically, green tea might reduce the effects of felbamate and increase the risk for convulsions.
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Green tea contains caffeine. Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate (23563). However, this effect has not been reported in humans.
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Green tea can decrease blood levels of fexofenadine.
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Clinical research shows that green tea can significantly decrease blood levels and excretion of fexofenadine. Taking green tea extract with a dose of fexofenadine decreased bioavailability of fexofenadine by about 30%. In vitro, green tea inhibits the cellular accumulation of fexofenadine by inhibiting the organic anion transporting polypeptide (OATP) drug transporter (111029). Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs, specifically OATP1A2, OATP1B1, and OATP2B1. In addition, green tea has been shown to reduce the absorption of some drugs that are OATP substrates (19079,102714,102730).
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Theoretically, fluconazole might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Fluconazole decreases caffeine clearance by approximately 25% (11022).
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Theoretically, green tea might increase the levels and adverse effects of flutamide.
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Green tea contains caffeine. In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide (23553). Theoretically, concomitant use of caffeine and flutamide might increase serum concentrations of flutamide and increase the risk adverse effects.
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Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Fluvoxamine reduces caffeine metabolism (6370).
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Theoretically, concomitant use might have additive adverse hepatotoxic effects.
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Theoretically, green tea might reduce the levels and clinical effects of imatinib.
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In animal research, a single dose of green tea extract reduces the area under the curve (AUC) of imatinib by up to approximately 64% and its main metabolite N-desmethyl imatinib by up to approximately 81% (104600). This interaction has not been shown in humans. The mechanism of action is unclear but may involve multiple pathways.
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Theoretically, green tea might reduce the levels and clinical effects of lisinopril.
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Preliminary clinical research shows that a single dose of green tea extract reduces plasma concentrations of lisinopril. Compared to a control group, peak levels and area under the curve (AUC) of lisinopril were reduced by approximately 71% and 66%, respectively (104599). This may be due to inhibition of organic anion transporting polypeptides (OATP) by green tea catechins (19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).
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Theoretically, abrupt green tea withdrawal might increase the levels and adverse effects of lithium.
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Theoretically, metformin might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Animal research suggests that metformin can reduce caffeine metabolism (23571). Theoretically, concomitant use can increase caffeine serum concentrations and the risk of caffeine adverse effects.
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Theoretically, methoxsalen might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Methoxsalen can reduce caffeine metabolism (23572). Concomitant use can increase caffeine serum concentrations and the risk of caffeine adverse effects.
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Theoretically, mexiletine might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Mexiletine can decrease caffeine elimination by 50% (1260).
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Theoretically, green tea might increase the levels and adverse effects of midazolam.
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Animal research suggests that green tea extract can increase the maximum plasma concentration, but not the half-life, of oral midazolam. This effect has been attributed to the inhibition of intestinal cytochrome P450 3A4 (CYP3A4) and induction of hepatic CYP3A4 enzymes by green tea constituents (20896). However, it is unlikely that this effect is clinically significant, as the dose used in animals was 50 times greater than what is commonly ingested by humans.
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Theoretically, concomitant use might increase the risk of a hypertensive crisis.
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Green tea contains caffeine. Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies (37724,37877,37912,38108). Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis (15). In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension (91086). Hypertension was resolved after the patient switched to drinking decaffeinated coffee.
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Green tea seems to reduce the levels and clinical effects of nadolol.
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Preliminary clinical research shows that green tea consumption reduces plasma concentrations of nadolol. Compared to a control group, both peak levels and total drug exposure (AUC) of nadolol were reduced by approximately 85% in subjects who drank green tea daily for two weeks. Drinking green tea with nadolol also significantly reduced nadolol's systolic blood pressure lowering effect (19071). Other clinical research shows that a single dose of green tea can affect plasma nadolol levels for at least one hour (102721). Green tea catechins have been shown to inhibit organic anion transporting polypeptides (OATP), one of which, OATP1A2, is involved in the uptake of nadolol in the intestine (19071,19079,19080,98461) The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea (98461).
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Theoretically, green tea might increase the levels and adverse effects of nicardipine.
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Green tea contains EGCG. Animal research shows that EGCG increases the area under the curve (AUC) and absolute oral bioavailability of nicardipine. The mechanism of action is thought to involve inhibition of both intestinal P-glycoprotein and hepatic cytochrome P450 3A (90136). The effect of green tea itself on nicardipine is unclear.
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Theoretically, concomitant use might increase the risk of hypertension.
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Green tea contains caffeine. Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly (36549).
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Green tea seems to reduce the levels of nintedanib.
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Clinical research shows that green tea can significantly decrease blood levels of nintedanib. Taking green tea extract twice daily for 7 days 30 minutes prior to a meal along with nintedanib with the meal decreased the 12-hour area under the curve (AUC) values for nintedanib by 21%. There was no effect on the maximum concentration of nintedanib (111028).
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Theoretically, green tea might reduce the absorption of organic anion-transporting polypeptide (OATP) substrates.
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OATPs are expressed in the small intestine and liver and are responsible for the uptake of drugs and other compounds. Research shows that two of the major catechins found in green tea, epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), inhibit OATPs, specifically OATP1A2, OATP1B1, and OATP2B1. In addition, green tea has been shown to reduce the absorption of some drugs that are OATP substrates, including lisinopril, and celiprolol (19079,102714,102730).
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Green tea might increase the levels and adverse effects of P-glycoprotein (P-gp) substrates.
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In vitro research and case reports suggest that green tea inhibits drug efflux by P-gp, potentially increasing serum levels of P-gp substrates. Case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking green tea and certain P-gp substrates (111644).
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Theoretically, green tea might decrease the effects of pentobarbital.
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Green tea contains caffeine. Theoretically, caffeine might negate the hypnotic effects of pentobarbital (13742).
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Theoretically, green tea might reduce the effects of phenobarbital and increase the risk for convulsions.
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Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.
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Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
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Theoretically, green tea might reduce the effects of phenytoin and increase the risk for convulsions.
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Theoretically, green tea might increase the levels and clinical effects of pioglitazone.
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Green tea contains caffeine. Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone (108812). However, the exact mechanism of this interaction is unclear.
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Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.
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Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
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Green tea contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2, and concomitant use might reduce metabolism of one or both agents (11739).
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Theoretically, green tea extract might alter the absorption and distribution of rosuvastatin.
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In animal research, giving green tea extract with rosuvastatin increased plasma levels of rosuvastatin. Rosuvastatin is a substrate of organic anion-transporting polypeptide (OATP)1B1, which is expressed in the liver. The increased plasma levels may have been related to inhibition of OATP1B1 (102717). However, in humans, taking EGCG with rosuvastatin reduced plasma levels of rosuvastatin, suggesting an inhibition of intestinal OATP (102730). It is not clear if drinking green tea alters the absorption of rosuvastatin.
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Theoretically, concomitant use might increase stimulant adverse effects.
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Green tea contains caffeine. Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects (11832).
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Theoretically, terbinafine might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. Terbinafine decreases the clearance of intravenous caffeine by 19% (11740).
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Theoretically, green tea might increase the levels and adverse effects of theophylline.
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Green tea contains caffeine. Large amounts of caffeine might inhibit theophylline metabolism (11741).
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Theoretically, green tea might increase the levels and adverse effects of tiagabine.
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Green tea contains caffeine. Animal research suggests that chronic caffeine administration can increase the serum concentrations of tiagabine. However, concomitant use does not seem to reduce the antiepileptic effects of tiagabine (23561).
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Theoretically, ticlopidine might increase the levels and adverse effects of caffeine.
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Green tea contains caffeine. In vitro evidence suggests that ticlopidine can inhibit caffeine metabolism (23557). However, this effect has not been reported in humans.
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Theoretically, green tea might reduce the effects of valproate and increase the risk for convulsions.
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Theoretically, concomitant use might increase the levels and adverse effects of both verapamil and caffeine.
Details
Animal research suggests that the green tea constituent EGCG increases the area under the curve (AUC) values for verapamil by up to 111% and its metabolite norverapamil by up to 87%, likely by inhibiting P-glycoprotein (90138). Also, theoretically, concomitant use of verapamil and caffeinated beverages such as green tea might increase plasma caffeine concentrations and the risk of adverse effects, due to the caffeine contained in green tea. Verapamil increases plasma caffeine concentrations by 25% (11741).
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Theoretically, green tea may increase the risk of bleeding if used with warfarin.
Details
Conflicting reports exist regarding the potential of green tea to antagonize the effect of warfarin; however, most evidence suggests that drinking green tea in moderation is unlikely to cause a significant interaction. Green tea contains a small amount of vitamin K, approximately 7 mcg per cup (100524). Some case reports have associated the antagonism of warfarin with the vitamin K content of green tea (1460,1461,1463,4211,6048,8028,20868). However, these reports are rare, and very large doses of green tea (about 8-16 cups daily) appear to be needed to cause these effects (1460,1461,1463,8028). Therefore, use of green tea in moderate amounts is unlikely to antagonize the effects of warfarin; however, very large doses should be avoided.
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Theoretically, licorice might reduce the effects of antihypertensive drugs.
Details
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Theoretically, licorice might reduce the effects of cisplatin.
Details
In animal research, licorice diminished the therapeutic efficacy of cisplatin (59763).
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Theoretically, concomitant use of licorice and corticosteroids might increase the side effects of corticosteroids.
Details
Case reports suggest that concomitant use of licorice and oral corticosteroids, such as hydrocortisone, can potentiate the duration of activity and increase blood levels of corticosteroids (3252,12672,20040,20042,48429,59756). Additionally, in one case report, a patient with neurogenic orthostatic hypertension stabilized on fludrocortisone 0.1 mg twice daily developed pseudohyperaldosteronism after recent consumption of large amounts of black licorice (108568).
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Theoretically, licorice might decrease the levels and clinical effects of CYP1A2 substrates.
Details
In vitro research shows that licorice induces CYP1A2 enzymes (111404).
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Theoretically, licorice might increase levels of drugs metabolized by CYP2B6.
Details
In vitro research shows that licorice extract and glabridin, a licorice constituent, inhibit CYP2B6 isoenzymes (10300,94822). Licorice extract from the species G. uralensis seems to inhibit CYP2B6 isoenzymes to a greater degree than G. glabra extract in vitro (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2B6; however, these interactions have not yet been reported in humans.
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Theoretically, licorice might increase levels of drugs metabolized by CYP2C19.
Details
In vitro, licorice extracts from the species G. glabra and G. uralensis inhibit CYP2C19 isoenzymes in vitro (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2C19; however, this interaction has not yet been reported in humans.
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Theoretically, licorice might increase levels of drugs metabolized by CYP2C8.
Details
In vitro, licorice extract from the species G. glabra and G. uralensis inhibits CYP2C8 isoenzymes (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2C8; however, this interaction has not yet been reported in humans.
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Theoretically, licorice might increase or decrease levels of drugs metabolized by CYP2C9.
Details
There is conflicting evidence about the effect of licorice on CYP2C9 enzyme activity. In vitro research shows that extracts from the licorice species G. glabra and G. uralensis moderately inhibit CYP2C9 isoenzymes (10300,94822). However, evidence from an animal model shows that licorice extract from the species G. uralensis can induce hepatic CYP2C9 activity (14441). Until more is known, licorice should be used cautiously in people taking CYP2C9 substrates.
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Theoretically, licorice might increase or decrease levels of drugs metabolized by CYP3A4.
Details
Pharmacokinetic research shows that the licorice constituent glycyrrhizin, taken in a dosage of 150 mg orally twice daily for 14 days, modestly decreases the area under the concentration-time curve of midazolam by about 20%. Midazolam is a substrate of CYP3A4, suggesting that glycyrrhizin modestly induces CYP3A4 activity (59808). Animal research also shows that licorice extract from the species G. uralensis induces CYP3A4 activity (14441). However, licorice extract from G. glabra species appear to inhibit CYP3A4-induced metabolism of testosterone in vitro. It is thought that the G. glabra inhibits CYP3A4 due to its constituent glabridin, which is a moderate CYP3A4 inhibitor in vitro and not present in other licorice species (10300,94822). Until more is known, licorice should be used cautiously in people taking CYP3A4 substrates.
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Theoretically, concomitant use of licorice with digoxin might increase the risk of cardiac toxicity.
Details
Overuse or misuse of licorice with cardiac glycoside therapy might increase the risk of cardiac toxicity due to potassium loss (10393).
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Theoretically, concomitant use of licorice with diuretic drugs might increase the risk of hypokalemia.
Details
Overuse of licorice might compound diuretic-induced potassium loss (10393,20045,20046,59812). In one case report, a 72-year-old male with a past medical history of hypertension, type 2 diabetes, hyperlipidemia, arrhythmia, stroke, and hepatic dysfunction was hospitalized with severe hypokalemia and uncontrolled hypertension due to pseudohyperaldosteronism. This was thought to be provoked by concomitant daily consumption of a product containing 225 mg of glycyrrhizin, a constituent of licorice, and hydrochlorothiazide 12.5 mg for 1 month (108577).
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Theoretically, licorice might increase or decrease the effects of estrogen therapy.
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Theoretically, loop diuretics might increase the mineralocorticoid effects of licorice.
Details
Theoretically, loop diuretics might enhance the mineralocorticoid effects of licorice by inhibiting the enzyme that converts cortisol to cortisone; however, bumetanide (Bumex) does not appear to have this effect (3255).
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Theoretically, licorice might increase levels of methotrexate.
Details
Animal research suggests that intravenous administration of glycyrrhizin, a licorice constituent, and high-dose methotrexate may delay methotrexate excretion and increase systemic exposure, leading to transient elevations in liver enzymes and total bilirubin (108570). This interaction has not yet been reported in humans.
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Theoretically, licorice might decrease levels of midazolam.
Details
In humans, the licorice constituent glycyrrhizin appears to moderately induce the metabolism of midazolam (59808). This is likely due to induction of cytochrome P450 3A4 by licorice. Until more is known, licorice should be used cautiously in people taking midazolam.
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Theoretically, licorice might decrease the absorption of P-glycoprotein substrates.
Details
In vitro research shows that licorice can increase P-glycoprotein activity (104561).
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Theoretically, licorice might decrease plasma levels and clinical effects of paclitaxel.
Details
Multiple doses of licorice taken concomitantly with paclitaxel might reduce the effectiveness of paclitaxel. Animal research shows that licorice 3 grams/kg given orally for 14 days before intravenous administration of paclitaxel decreases the exposure to paclitaxel and increases its clearance. Theoretically, this occurs because licorice induces cytochrome P450 3A4 enzymes, which metabolize paclitaxel. Notably, a single dose of licorice did not affect exposure or clearance of paclitaxel (102959).
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Theoretically, licorice might decrease plasma levels and clinical effects of warfarin.
Details
Licorice seems to increase metabolism and decrease levels of warfarin in animal models. This is likely due to induction of cytochrome P450 2C9 (CYP2C9) metabolism by licorice (14441). Advise patients taking warfarin to avoid taking licorice.
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Theoretically, senna might increase the risk of adverse effects when taken with digoxin.
Details
Overuse/abuse of senna increases the risk of adverse effects from cardiac glycosides, such as digoxin, due to potassium depletion (15425).
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Theoretically, senna might increase the risk of hypokalemia when taken with diuretic drugs.
Details
Overuse of senna might compound diuretic-induced potassium loss and increase the risk for hypokalemia (15425).
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Theoretically, taking senna may interfere with the absorption of exogenous estrogens.
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Theoretically, senna might increase the risk for fluid and electrolyte loss when taken with other stimulant laxatives.
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Theoretically, excessive use of senna might increase the effects of warfarin.
Details
Senna has stimulant laxative effects and can cause diarrhea. Diarrhea can increase the effects of warfarin, increase international normalized ratio (INR), and increase the risk of bleeding. In one case report, excessive use of senna for 3 weeks resulted in diarrhea, bloody stools, and an elevated INR of 11.9 (16530).
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Below is general information about the adverse effects of the known ingredients contained in the product Green Tea Herbal Slimming Tea. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
General
...Orally, green tea is generally well tolerated when consumed as a beverage in moderate amounts.
Green tea extract also seems to be well tolerated when used for up to 12 months.
Most Common Adverse Effects:
Orally: Bloating, constipation, diarrhea, dyspepsia, flatulence, and nausea.
Serious Adverse Effects (Rare):
Orally: Hepatotoxicity, hypokalemia, and thrombotic thrombocytopenic purpura have been reported rarely.
Cardiovascular
...Acute or short-term oral administration of green tea may cause hypertension (53719,54014,54065,54076,102716).
The risk may be greater for green tea products containing more than 200 mg epigallocatechin gallate (EGCG) (90161). However, consumption of brewed green tea does not seem to increase blood pressure or pulse, even in mildly hypertensive patients (1451,1452). In fact, some evidence suggests that habitual tea consumption is associated with a reduced risk of developing hypertension (12518). Also, epidemiological research suggests there is no association of caffeine consumption with incidence of hypertension or with cardiovascular disease mortality in patients with hypertension (13739,111027). Rarely, green tea consumption may cause hypotension (53867).
Epidemiological research suggests that regular caffeine intake of up to 400 mg per day, or approximately 8 cups of green tea, is not associated with an increased incidence of atrial fibrillation (38018,38076,91028,91034,97451,97453), atherosclerosis (38033), cardiac ectopy (91127), stroke (37804), ventricular arrhythmia (95948,97453), and cardiovascular disease in general (37805,98806).
Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, and temporary loss of consciousness has been associated with the combined use of ephedra and caffeine (2729). There is also a report of ischemic stroke in an athlete who consumed ephedra 40-60 mg, creatine monohydrate 6 grams, caffeine 400-600 mg, and a variety of other supplements daily for 6 weeks (1275). In theory, combining caffeinated green tea with ephedra would have similar effects.
In a case report, the EGCG component of a specific weight loss supplement (Hydroxycut) was thought to be responsible for atrial fibrillation (54028). The patient was given two doses of intravenous diltiazem and was loaded with intravenous digoxin. Thirty-six hours after the last product dose, she spontaneously converted to normal sinus rhythm. The authors suggested that the block of the atrial-specific KCNA5 potassium channel likely played a role in this response.
A case of thrombotic thrombocytopenic purpura has been reported for a patient who consumed a weight loss product containing green tea (53978). She presented at the emergency department with a one-week history of malaise, fatigue, and petechiae of the skin. Twelve procedures of plasmapheresis were performed, and corticosteroid treatment was initiated. She was discharged after 20 days.
Dermatologic ...Orally, green tea may cause skin rashes or skin irritation (53731,54038,90161,90187,102716). Topically, green tea may cause local skin reactions or skin irritation, erythema, burning, itching, edema, and erosion (53731,54018,97136,104609,111031). A green tea extract ointment applied to the cervix can cause cervical and vaginal inflammation, vaginal irritation, and vulval burning (11310,36442,36438). When applied to external genital or perianal warts, a specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins can cause erythema, pruritus, local pain, discomfort and burning, ulceration, induration, edema, and vesicular rash (15067,53907).
Endocrine
...There is some concern that, due to its caffeine content, green tea may be associated with an increased risk of fibrocystic breast disease, breast cancer, and endometriosis.
However, this is controversial since findings are conflicting (8043). Restricting caffeine in females with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain (8996).
A population analysis of the Women's Health Initiative observational study has found no association between consumption of caffeine-containing beverages, such as green tea, and the incidence of invasive breast cancer in models adjusted for demographic, lifestyle, and reproductive factors (108806). Also, a dose-response analysis of 2 low-quality observational studies has found that high consumption of caffeine is not associated with an increased risk of breast cancer (108807).
A case of hypoglycemia has been reported for a clinical trial participant with type 2 diabetes who used green tea in combination with prescribed antidiabetes medication (54035).
Gastrointestinal ...Orally, green tea beverage or supplements can cause nausea, vomiting, abdominal bloating and pain, constipation, dyspepsia, reflux, morning anorexia, increased thirst, flatulence, and diarrhea. These effects are more common with higher doses of green tea or green tea extract, equivalent to 5-6 liters of tea per day (8117,11366,36398,53719,53867,53936,54038,54076,90139,90140)(90161,90175,90187,97131,97136,102716).
Hepatic
...There is concern that some green tea products, especially green tea extracts, can cause hepatotoxicity in some patients.
In 2017, the regulatory agency Health Canada re-issued a warning to consumers about this concern. The updated warning advises patients taking green tea extracts, especially those with liver disease, to watch for signs of liver toxicity. It also urges children to avoid taking products containing green tea extracts (94897). In 2020, the United States Pharmacopeia (USP) formed an expert panel to review concerns of green tea extract-related hepatotoxicity. Based on their findings, USP determined that any products claiming compliance with USP quality standards for green tea extract must include a specific warning on the label stating "Do not take on an empty stomach. Take with food. Do not use if you have a liver problem and discontinue use and consult a healthcare practitioner if you develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice (yellowing of the skin or eyes)" (102722).
Numerous case reports of hepatotoxicity, primarily linked to green tea extract products taken in pill form, have been published. A minimum of 29 cases have been deemed at least probably related to green tea and 38 have been deemed possibly related. In addition, elevated liver enzymes have been reported in clinical research (14136,15026,53740,53746,53775,53859,54027,90139,90162,90164)(93256,94898,94899,102716,102720,102722,107158,111020,111644). Most cases of toxicity have had an acute hepatitis-like presentation with a hepatocellular-elevation of liver enzymes and some cholestasis. Onset of hepatotoxic symptoms usually occurs within 3 months after initiation of the green tea extract supplement, and symptoms can persist from 10 days to 1 year (95439,94897,94898,107158). Some reports of hepatotoxicity have been associated with consumption of green tea-containing beverages as well (15026,53742,54016,90125,90143).
In most cases, liver function returned to normal after discontinuation of the green tea product (14136,15026,53859,93256,107158). In one case, use of a specific ethanolic green tea extract (Exolise, Arkopharma) resulted in hepatotoxicity requiring a liver transplant. Due to concerns about hepatotoxicity, this specific extract was removed from the market by the manufacturer (14310). Since then, at least 5 cases of liver toxicity necessitating liver transplantation have been reported for patients who used green tea extracts (94898,107158). In another case, use of green tea (Applied Nutrition Green Tea Fat Burner) in combination with whey protein, a nutritional supplement (GNC Mega Men Sport), and prickly pear cactus resulted in acute liver failure (90162).
Despite the numerous reports of hepatotoxicity associated with the use of green tea products, the actual number of hepatotoxicity cases is low when the prevalence of green tea use is considered. From 2006 to 2016, liver injury from green tea products was estimated have occurred in only 1 out of 2.7 million patients who used green tea products (94897,95440).
In addition to the fact that green tea hepatotoxicity is uncommon, it is also not clear which patients are most likely to experience liver injury (94897,95440). The hepatotoxicity does not appear to be an allergic reaction or an autoimmune reaction (94897). It is possible that certain extraction processes, for example, ethanolic extracts, produce hepatotoxic constituents. However, in most cases, the presence of contaminants in green tea products has not been confirmed in laboratory analyses (90162).
Although results from one analysis of 4 small clinical studies disagrees (94899), most analyses of clinical data, including one conducted by the European Food Safety Association, found that hepatotoxicity from green tea products is associated with the dose of EGCG in the green tea product. Results show that daily intake of EGCG in amounts greater than or equal to 800 mg per day is associated with a higher incidence of elevated liver enzymes such as alanine transaminase (ALT) (95440,95696,97131). However, it is still unclear what maximum daily dose of EGCG will not increase liver enzyme levels or what minimum daily dose of EGCG begins to cause liver injury. In many cases of liver injury, the dose of green tea extract and/or EGCG is not known. Therefore, a minimum level of green tea extract or EGCG that would cause liver injury in humans cannot be determined (102722). Keep in mind that daily intake of green tea infusions provides only 90-300 mg of EGCG daily. So for a majority of people, green tea infusions are likely safe and unlikely to cause liver injury (95696). Also, plasma levels of EGCG are increased when green tea catechins are taken in the fasting state, suggesting that green tea extract should be taken with food (102722).
Until more is known, advise patients that green tea products, especially those containing green tea extract, might cause liver damage. However, let them know that the risk is uncommon, and it is not clear which products are most likely to cause the adverse effect or which patients are most likely to be affected. Advise patients with liver disease to consult their healthcare provider before taking products with green tea extract and to notify their healthcare provider if they experience symptoms of liver damage, including jaundice, dark urine, sweating, or abdominal pain (102722).
Immunologic ...Orally, matcha tea has resulted in at least one case of anaphylaxis related to green tea proteins. A 9-year-old male experienced systemic redness and hives, nausea, and anaphylaxis 60 minutes after consuming matcha tea-flavored ice cream (107169). The caffeine found in green tea can also cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare (11315).
Musculoskeletal
...Orally, the ingestion of the green tea constituent epigallocatechin gallate (EGCG) or a decaffeinated green tea polyphenol mixture may cause mild muscle pain (36398).
There is some concern regarding the association between caffeinated green tea products and osteoporosis. Epidemiological evidence regarding the relationship between caffeinated beverages such as green tea and the risk for osteoporosis is contradictory. Caffeine can increase urinary excretion of calcium (2669,10202,11317). Females with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass (2669). However, moderate caffeine intake of less than 400 mg per day, or about 8 cups of green tea, doesn't seem to significantly increase osteoporosis risk in most postmenopausal adults with normal calcium intake (2669,6025,10202,11317).
Neurologic/CNS
...Orally, green tea can cause central nervous system stimulation and adverse effects such as headache, anxiety, dizziness, insomnia, fatigue, agitation, tremors, restlessness, and confusion.
These effects are more common with higher doses of green tea or green tea extract, equivalent to 5-6 liters of tea per day (8117,11366,53719,90139,102716). The green tea constituent epigallocatechin gallate (EGCG) or decaffeinated green tea may also cause mild dizziness and headache (36398).
Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, temporary loss of consciousness, and hospitalization requiring life support has been associated with the combined use of ephedra and caffeine (2729).
Topically, green tea extract (Polyphenon E ointment) may cause headache when applied to the genital area (36442).
Psychiatric ...Green tea contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, and psychological dependence (11832). The existence or clinical importance of caffeine withdrawal is controversial. Some researchers think that if it exists, it appears to be of little clinical significance (11839). Other researchers suggest symptoms such as headache; tiredness and fatigue; decreased energy, alertness, and attentiveness; drowsiness; decreased contentedness; depressed mood; difficulty concentrating; irritability; and lack of clear-headedness are typical of caffeine withdrawal (13738). Withdrawal symptoms such as delirium, nausea, vomiting, rhinorrhea, nervousness, restlessness, anxiety, muscle tension, muscle pains, and flushed face have been described. However, these symptoms may be from nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839).
Pulmonary/Respiratory ...A case of granulomatous alveolitis with lymph follicles has been reported for a 67-year-old female who used green tea infusions to wash her nasal cavities for 15 years (54088). Her symptoms disappeared 2 months after stopping this practice and following an undetermined course of corticosteroids. In a case report, hypersensitivity pneumonitis was associated with inhalation of catechin-rich green tea extracts (54025). Occupational exposure to green tea dust can cause sensitization, which may include nasal and asthmatic symptoms (11365).
Renal ...There are two cases of hypokalemia associated with drinking approximately 8 cups daily of green tea in an elderly couple of Asian descent. The hypokalemia improved after reducing their intake by 50%. It is possible that this was related to the caffeine in the green tea (98418).
Other ...Orally, intake of a specific green tea extract product (Polyphenon E) may cause weight gain (90139).
General
...Orally, licorice is generally well tolerated when used in amounts commonly found in foods.
It seems to be well tolerated when licorice products that do not contain glycyrrhizin (deglycyrrhizinated licorice) are used orally and appropriately for medicinal purposes or when used topically, short-term.
Most Common Adverse Effects:
Orally: Headache, nausea, and vomiting.
Topically: Contact dermatitis.
Intravenously: Diarrhea, itching, nausea, and rash.
Serious Adverse Effects (Rare):
Orally: Case reports have raised concerns about acute renal failure, cardiac arrest, cardiac arrhythmias, hypertension, hypokalemia, muscle weakness, paralysis, pseudohyperaldosteronism, and seizure associated with long-term use or large amounts of licorice containing glycyrrhizin.
Cardiovascular
...Orally, excessive licorice ingestion can lead to pseudohyperaldosteronism, which can precipitate cardiovascular complications such as hypertension and hypertensive crisis, ventricular fibrillation or tachycardia, sinus pause, and cardiac arrest.
These effects are due to the licorice constituent glycyrrhizin and usually occur when 20-30 grams or more of licorice product is consumed daily for several weeks (781,15590,15592,15594,15596,15597,15599,15600,16835,97213) (104563,108574,108576,110305,112234). In one case report, an 89-year-old female taking an herbal medicine containing licorice experienced a fatal arrhythmia secondary to licorice-induced hypokalemia. The patient presented to the hospital with recurrent syncope, weakness, and fatigue for 5 days after taking an herbal medicine containing licorice for 2 months. Upon admission to the hospital, the patient developed seizures, QT prolongation, and ventricular arrhythmia requiring multiple defibrillations. Laboratory tests confirmed hypokalemia and pseudohyperaldosteronism (112234).
However, people with cardiovascular or kidney conditions may be more sensitive, so these adverse events may occur with doses as low as 5 grams of licorice product or glycyrrhizin 100 mg daily (15589,15593,15598,15600,59726). A case report in a 54-year-old male suggests that malnutrition might increase the risk of severe adverse effects with excessive licorice consumption. This patient presented to the emergency room with cardiac arrest and ventricular fibrillation after excessive daily consumption of licorice for about 3 weeks. This caused pseudohyperaldosteronism and then hypokalemia, leading to cardiovascular manifestations. In spite of resuscitative treatment, the patient progressed to kidney failure, refused dialysis, and died shortly thereafter (103791).
Dermatologic
...There have been reports of contact allergy, resulting in an itchy reddish eruption, occurring in patients that applied cosmetic products containing oil-soluble licorice extracts (59912).
There have also been at least 3 cases of allergic contact dermatitis reported with the topical application of glycyrrhizin-containing products to damaged skin. In one case report, a 31-year-old female with acne presented with a 2-year history of pruritic erythematous-scaly plaques located predominantly on the face and neck after the use of a cosmetic product containing licorice root extract 1%. The patient had a positive skin patch test to licorice root extract, leading the clinicians to hypothesize that the use of benzoyl peroxide, a strong irritant, might have sensitized the patient to licorice (108578). Burning sensation, itching, redness, and scaling were reported rarely in patients applying a combination of licorice, calendula, and snail secretion filtrate to the face. The specific role of licorice is unclear (110322).
In rare cases, the glycyrrhizin constituent of licorice has caused rash and itching when administered intravenously (59712).
Endocrine
...Orally, excessive licorice ingestion can cause a syndrome of apparent mineralocorticoid excess, or pseudohyperaldosteronism, with sodium and water retention, increased urinary potassium loss, hypokalemia, and metabolic alkalosis due to its glycyrrhizin content (781,10619,15591,15592,15593,15594,15595,15596,15597,15598)(15600,16057,16835,25659,25660,25673,25719,26439,59818,59822)(59832,59864,91722,104563,108568,108574,110305,112234).
These metabolic abnormalities can lead to hypertension, edema, EKG changes, fatigue, syncope, arrhythmias, cardiac arrest, headache, lethargy, muscle weakness, dropped head syndrome (DHS), rhabdomyolysis, myoglobinuria, paralysis, encephalopathy, respiratory impairment, hyperparathyroidism, and acute kidney failure (10393,10619,15589,15590,15593,15594,15596,15597,15599)(15600,16057,16835,25660,25673,25719,26439,31562,59709,59716)(59720,59740,59787,59820,59826,59882,59889,59900,91722,97214,100522) (104563,108576,108577). These effects are most likely to occur when 20-30 grams of licorice products containing glycyrrhizin 400 mg or more is consumed daily for several weeks (781,15590,15592,15594,15596,15597,15599,15600,16835,108574). However, some people may be more sensitive, especially those with hypertension, diabetes, heart problems, or kidney problems (15589,15593,15598,15600,59726,108576,108577) and even low or moderate consumption of licorice may cause hypertensive crisis or hypertension in normotensive individuals (1372,97213). The use of certain medications with licorice may also increase the risk of these adverse effects (108568,108577). One case report determined that the use of large doses of licorice in an elderly female stabilized on fludrocortisone precipitated hypokalemia and hypertension, requiring inpatient treatment (108568). Another case report describes severe hypokalemia necessitating intensive care treatment due to co-ingestion of an oral glycyrrhizin-specific product and hydrochlorothiazide for 1 month (108577). Glycyrrhetinic acid has a long half-life, a large volume of distribution, and extensive enterohepatic recirculation. Therefore, it may take 1-2 weeks before hypokalemia resolves (781,15595,15596,15597,15600). Normalization of the renin-aldosterone axis and blood pressure can take up to several months (781,15595,108568). Treatment typically includes the discontinuation of licorice, oral and intravenous potassium supplementation, and short-term use of aldosterone antagonists, such as spironolactone (108574,108577).
Chewing tobacco flavored with licorice has also been associated with toxicity. Chewing licorice-flavored tobacco, drinking licorice tea, or ingesting large amounts of black licorice flavored jelly beans or lozenges has been associated with hypertension and suppressed renin and aldosterone levels (12671,12837,97214,97215,97217,108574). One case report suggests that taking a combination product containing about 100 mg of licorice and other ingredients (Jintan, Morishita Jintan Co.) for many decades may be associated with hypoaldosteronism, even up to 5 months after discontinuation of the product (100522). In another case report, licorice ingestion led to hyperprolactinemia in a female (59901). Licorice-associated hypercalcemia has also been noted in a case report (59766).
Gastrointestinal ...Nausea and vomiting have been reported rarely following oral use of deglycyrrhizinated licorice (25694,59871). Intravenously, the glycyrrhizin constituent of licorice has rarely caused gastric discomfort, diarrhea, or nausea (59712,59915).
Immunologic ...There have been reports of contact allergy, resulting in an itchy reddish eruption, occurring in patients that applied cosmetic products containing oil-soluble licorice extracts (59912). There have also been at least 3 cases of allergic contact dermatitis reported with the topical application of glycyrrhizin-containing products to damaged skin. In one case report, a 31-year-old female with acne presented with a 2-year history of pruritic erythematous-scaly plaques located predominantly on the face and neck after the use of a cosmetic product containing licorice root extract 1%. The patient had a positive skin patch test to licorice root extract, leading the clinicians to hypothesize that the use of benzoyl peroxide, a strong irritant, might have sensitized the patient to licorice (108578).
Musculoskeletal ...In a case report, excessive glycyrrhizin-containing licorice consumption led to water retention and was thought to trigger neuropathy and carpal tunnel syndrome (59791).
Neurologic/CNS ...Orally, licorice containing larger amounts of glycyrrhizin may cause headaches. A healthy woman taking glycyrrhizin 380 mg daily for 2 weeks experienced a headache (59892). Intravenously, the glycyrrhizin constituent of licorice has rarely caused headaches or fatigue (59721). In a case report, licorice candy ingestion was associated with posterior reversible encephalopathy syndrome accompanied by a tonic-clonic seizure (97218).
Ocular/Otic ...Orally, consuming glycyrrhizin-containing licorice 114-909 grams has been associated with transient visual loss (59714).
Pulmonary/Respiratory ...Orally, large amounts of licorice might lead to pulmonary edema. In one case report, a 64-year old male consumed 1020 grams of black licorice (Hershey Twizzlers) containing glycyrrhizin 3.6 grams over 3 days, which resulted in pulmonary edema secondary to pseudohyperaldosteronism (31561). Intravenously, the glycyrrhizin constituent of licorice has caused cold or flu-like symptoms, although these events are not common (59712,59721).
General
...Orally, senna is generally well-tolerated when used short-term in appropriate doses.
Most Common Adverse Effects:
Orally: Abdominal pain and discomfort, cramps, diarrhea, flatulence, nausea, fecal urgency, and urine discoloration.
Serious Adverse Effects (Rare):
Orally: Skin eruptions.
Cardiovascular ...Excessive use can cause potassium depletion and other electrolyte abnormalities (15425). In theory, this could cause potentially dangerous changes in heart rhythm. A small decrease in heart rate was seen in one clinical study (74587).
Dermatologic ...In adults, there are rare case reports of skin eruptions associated with senna, including erythema multiforme, fixed drug eruption, lichenoid reaction, toxic epidermal necrolysis, urticaria, photosensitivity, and contact dermatitis (96558). Infants and young children given senna products have experienced contact reactions on the buttocks due to prolonged exposure to stool while wearing a diaper overnight. These reactions range from erythema with small blisters, to large fluid-filled blisters with skin sloughing, as occurs with second degree burns (96559). In a case series of children treated with senna for chronic constipation, burn-like reactions occurred in 2.2%, typically with higher doses (mean 60 mg/day, range 35.2 to 150 mg/day) (96558,96559). These reactions can be avoided by giving senna early in the day, so that bowel movements occur at a time when diapers can be changed quickly (96559).
Gastrointestinal ...Orally, senna can cause abdominal pain and discomfort, cramps, bloating, flatulence, nausea, fecal urgency, and diarrhea (15427,15434,15435,15436,15439,15440,15441,105955). Chronic use has also been associated with "cathartic colon," radiographically diagnosed anatomical changes to the colon such as benign narrowing, colonic dilation, and loss of colonic folds (15428). The clinical relevance of these findings is unclear. Chronic use can also cause pseudomelanosis coli (pigment spots in intestinal mucosa) which is harmless, usually reverses with discontinuation, and is not associated with an increased risk of developing colorectal adenoma or carcinoma (6138). The cathartic properties of senna leaf are greater than the fruit (15430). Thus, the American Herbal Products Association only warns against long-term use of senna leaf (12).
Hepatic ...Chronic liver damage, portal vein thrombosis, and hepatitis have been reported following oral use of senna alkaloids, such as in tea made from senna leaves (13057,13095,41431,74560,74564,74584,105956). There is a case report of hepatitis in a female who consumed moderate amounts of senna tea. The patient was a poor metabolizer of cytochrome P450 2D6 (CYP2D6). It's thought that moderate doses of senna in this patient led to toxic hepatitis due to the patient's reduced ability to metabolize and eliminate the rhein anthrone metabolites of senna, which are thought to cause systemic toxicity (13057). There is also a case of liver failure, encephalopathy, and renal insufficiency in a female who consumed 1 liter/day of senna tea, prepared from 70 grams of dried senna fruit, over 3 years (13095). In another case report, a 3-year-old female presented with hepatitis that led to pancytopenia after drinking tea made from 2-3 grams dry senna leaves three times or more weekly for over one year (105956).
Immunologic ...In one case report, a 19-year-old male developed anaphylaxis with dyspnea, facial edema, and hives. This reaction was determined to be caused by the senna content in a specific combination product (Delgaxan Plus, Pompadour Ibérica) that the patient ingested (105957).
Musculoskeletal ...Hypertrophic osteoarthropathy, finger clubbing, cachexia, and tetany have been reported from excessive oral senna use in humans (15426,74580,74582,74620,74625).
Renal ...Nephrocalcinosis has been reported as a result of oral senna overuse (74582).
