Liporidex Max Ingredients & Drug Interactions

Theoretically, taking ashwagandha with antidiabetes drugs might increase the risk of hypoglycemia.
There is preliminary clinical evidence suggesting that ashwagandha might lower blood glucose levels. Theoretically, ashwagandha might have additive effects when used with antidiabetes drugs and increase the risk of hypoglycemia.

Theoretically, taking ashwagandha with antihypertensive drugs might increase the risk of hypotension.
Animal research suggests that ashwagandha might lower systolic and diastolic blood pressure. Theoretically, ashwagandha might have additive effects when used with antihypertensive drugs and increase the risk of hypotension.

Theoretically, taking ashwagandha might increase the sedative effects of benzodiazepines.
There is preliminary evidence that ashwagandha might have an additive effect with diazepam (Valium) and clonazepam (Klonopin). This may also occur with other benzodiazepines.

Theoretically, taking ashwagandha might increase the sedative effects of CNS depressants.
Ashwagandha seems to have sedative effects. Theoretically, this may potentiate the effects of barbiturates, other sedatives, and anxiolytics.

Theoretically, taking ashwagandha with hepatotoxic drugs might increase the risk of liver damage.
Ashwagandha has been linked to cases of acute hepatitis, liver failure, hepatic encephalopathy, autoimmune hepatitis, the need for liver transplantation, and death due to liver failure.

Theoretically, taking ashwagandha might decrease the effects of immunosuppressants.
Ashwagandha has demonstrated immunostimulant effects in humans. Animal research has shown that ashwagandha can attenuate the immunosuppression caused by cyclophosphamide.

Ashwagandha might increase the effects and adverse effects of thyroid hormone.
Concomitant use of ashwagandha with thyroid hormones may cause additive therapeutic and adverse effects. Preliminary clinical research and animal studies suggest that ashwagandha boosts thyroid hormone synthesis and secretion. In one clinical study, ashwagandha increased triiodothyronine (T3) and thyroxine (T4) levels by 41.5% and 19.6%, respectively, and reduced serum TSH levels by 17.4% from baseline in adults with subclinical hypothyroidism.

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that ashwagandha extract induces CYP1A2 enzymes.

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that ashwagandha extract induces CYP3A4 enzymes.

Some animal studies have reported that ashwagandha can enhance serotonergic transmission by altering certain serotonin (5-HT) receptors. However, there is no evidence to suggest that ashwagandha increases the risk of serotonin-related effects, and there have been no published case reports of serotonin syndrome when combined with other serotonergic drugs. Nevertheless, due to the lack of extensive studies on the matter and the fact that ashwagandha appears to affect serotonergic pathways, it would be prudent to exercise caution when combining it with drugs that affect serotonin. [References: - Effects of Withania somnifera (Ashwaga ndha) on Stress and the Stress-Related Neuropsychiatric Disorders Anxiety, Depression, and Insomnia. Curr Neuropharmacol. 2021 Sep 14; 19: 1468–1495. - A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in Adults. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3573577/]

Green tea extract seems to reduce the levels and clinical effects of atorvastatin.
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. 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. It is not clear if drinking green tea alters the absorption of atorvastatin.

Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Green tea contains caffeine. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death.

Green tea seems to reduce the levels and clinical effects of nadolol.
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. Other clinical research shows that a single dose of green tea can affect plasma nadolol levels for at least one hour. 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 The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea.

Theoretically, high doses of green tea might increase the effects and side effects of 5-fluorouracil.
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%.

Theoretically, green tea might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
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. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Theoretically, green tea may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
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. Some case reports have associated the antagonism of warfarin with the vitamin K content of green tea. 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.

Green tea contains caffeine. Theoretically, concomitant use of large amounts of caffeine might increase cardiac inotropic effects of beta-agonists.

Theoretically, green tea might interfere with the effects of bortezomib.
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. Advise patients taking bortezomib, not to take green tea.

Theoretically, green tea might reduce the effects of carbamazepine and increase the risk for convulsions.
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. 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.

Theoretically, green tea might reduce the levels and clinical effects of celiprolol.
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%. 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 The interaction is thought to be due primarily to the epigallocatechin gallate (EGCG) content of green tea.

Theoretically, concomitant use might increase the effects and adverse effects of caffeine in green tea.
Green tea contains caffeine. Cimetidine can reduce caffeine clearance by 31% to 42%.

Theoretically, green tea might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
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. 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. 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.

Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in green tea.
Green tea contains caffeine. Oral contraceptives can decrease caffeine clearance by 40% to 65%.

Theoretically, concomitant use might increase the levels and adverse effects of caffeine.
Green tea contains caffeine. Caffeine is metabolized by cytochrome P450 1A2 (CYP1A2),. Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from green tea and increase caffeine levels.

Theoretically, green tea might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Green tea contains caffeine. Caffeine might inhibit dipyridamole-induced vasodilation. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
In human research, disulfiram decreases the clearance and increases the half-life of caffeine.

Theoretically, using green tea with diuretic drugs might increase the risk of hypokalemia.
Green tea contains caffeine. In excessive amounts, caffeine can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.

Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Green tea contains caffeine. Estrogen inhibits caffeine metabolism.

Theoretically, green tea might reduce the effects of ethosuximide and increase the risk for convulsions.
Green tea contains caffeine. Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide. However, this effect has not been reported in humans.

Theoretically, green tea might reduce the effects of felbamate and increase the risk for convulsions.
Green tea contains caffeine. Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate. However, this effect has not been reported in humans.

Green tea can decrease blood levels of fexofenadine.
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. 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.

Theoretically, green tea might increase the levels and adverse effects of flutamide.
Green tea contains caffeine. In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide. Theoretically, concomitant use of caffeine and flutamide might increase serum concentrations of flutamide and increase the risk adverse effects.

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Green tea contains caffeine. Fluvoxamine reduces caffeine metabolism.

Theoretically, concomitant use might have additive adverse hepatotoxic effects.
Green tea extract supplements have been linked to several cases of hepatotoxicity and might have additive hepatotoxic effects with other drugs..

Theoretically, green tea might reduce the levels and clinical effects of imatinib.
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%. This interaction has not been shown in humans. The mechanism of action is unclear but may involve multiple pathways.

Theoretically, taking rhodiola with antidiabetes drugs might increase the risk of hypoglycemia.
In vitro and animal research shows that rhodiola extract can decrease blood glucose due to alpha-glucosidase activity.

Theoretically, taking rhodiola with antihypertensive drugs might increase the risk of hypotension.
In vitro and animal research shows that rhodiola extract inhibits angiotensin-converting enzyme (ACE) and might lower blood pressure.

Theoretically, rhodiola might increase levels of drugs metabolized by CYP2C9.
In vitro research shows that rhodiola inhibits CYP2C9. This effect is highly variable and appears to be dependent on the rhodiola product studied. Also, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days reduces the metabolism of losartan, a CYP2C9 substrate, by 21% after 4 hours.

Theoretically, rhodiola use might interfere with immunosuppressive therapy.
In vitro and animal research show that rhodiola has immunostimulatory effects.

Rhodiola might increase the levels and adverse effects of losartan.
A clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days reduces the metabolism of losartan, a CYP2C9 substrate, by 21% after 4 hours.

Theoretically, rhodiola might increase levels of P-glycoprotein substrates.
In vitro research shows that rhodiola inhibits P-glycoprotein. Theoretically, using rhodiola with P-glycoprotein substrates might increase drug levels and potentially increase the risk of adverse effects.

Theoretically, rhodiola might increase the risk of adverse effects when taken with antidepressants.
A review of adverse event reports in Poland identified cases of tachyarrhythmias, myalgia, arthralgia, gum pain, restless leg syndrome, swallowing disorders, and changes in consciousness when rhodiola was taken in combination with paroxetine, escitalopram, fluoxetine, sertraline, trazodone, and/or duloxetine.

Theoretically, rhodiola might increase the risk of adverse effects when taken with CNS depressants.
A review of adverse event reports in Poland identified cases of excessive sedation, myoclonus, hypotension, and hallucinations when rhodiola was taken with haloperidol, diazepam, or alprazolam.

Theoretically, rhodiola might increase levels of drugs metabolized by CYP1A2.
In vitro research shows that rhodiola inhibits CYP1A2. This effect is highly variable and appears to be dependent on the rhodiola product studied. However, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days does not inhibit the metabolism of caffeine, a CYP1A2 substrate.

Theoretically, rhodiola might increase levels of drugs metabolized by CYP3A4.
In vitro research shows that rhodiola inhibits CYP3A4. This effect is highly variable and appears to be dependent on the rhodiola product studied. However, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days does not inhibit the metabolism of midazolam, a CYP3A4 substrate.

Theoretically, concomitant use of quercetin and antidiabetes drugs might increase the risk of hypoglycemia.

Clinical research suggests that a combination of quercetin, myricetin, and chlorogenic acid reduce levels of fasting glucose in patients with type 2 diabetes, including those already taking antidiabetes agents. The effect of quercetin alone is unknown.

Theoretically, taking quercetin with antihypertensive drugs might increase the risk of hypotension.

Quercetin can modestly decrease blood pressure in people with mild hypertension. Theoretically, it might have additive blood pressure lowering effects when used with antihypertensive drugs.

Theoretically, concomitant use might increase the levels and adverse effects of cyclosporine.

A small study in healthy volunteers shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of a single dose of cyclosporine, possibly due to inhibition of p-glycoprotein or cytochrome P450 3A4 (CYP3A4), which metabolizes cyclosporin.

Theoretically, concomitant use might increase the levels and adverse effects of CYP2C8 substrates.

In vitro research shows that quercetin inhibits CYP2C8. Inhibition of paclitaxel (Taxol) metabolism via CYP2C8 has been reported in vitro. However, a small study in humans found no effect of quercetin on rosiglitazone (Avandia), which is also a CYP2C8 substrate.

Theoretically, concomitant use might increase the levels and adverse effects of CYP2C9 substrates.

A small clinical study in healthy volunteers shows that taking quercetin 500 mg twice daily for 10 days prior to taking diclofenac, a CYP2C9 substrate, increases diclofenac plasma levels by 75% and prolongs the half-life by 32.5%. Animal research also shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of losartan (Cozaar), a substrate of CYP2C9. Furthermore, laboratory research shows that quercetin inhibits CYP2C9.

Theoretically, concomitant use might increase the levels and adverse effects of CYP2D6 substrates.

In vitro research show that quercetin inhibits CYP2D6. This effect has not been reported in humans.

Theoretically, concomitant use might alter the effects and adverse effects of CYP3A4 substrates.
A small clinical study in healthy volunteers shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of a single dose of cyclosporine (Neoral, Sandimmune), a substrate of CYP3A4. Animal research also shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of losartan (Cozaar) and quetiapine (Seroquel), substrates of CYP3A4. Other laboratory research also shows that quercetin inhibits CYP3A4. However, one clinical study shows that quercetin can increase the metabolism of midazolam, a substrate of CYP3A4, and decrease serum concentrations of midazolam by about 24% in some healthy individuals, suggesting possible induction of CYP3A4.

Theoretically, concomitant use might increase the levels and adverse effects of diclofenac.

A small clinical study in healthy volunteers shows that taking quercetin 500 mg twice daily for 10 days prior to taking diclofenac increases diclofenac plasma levels by 75% and prolongs the half-life by 32.5%. This is thought to be due to inhibition of CYP2C9 by quercetin.

Theoretically, concomitant use might increase the effects and adverse effects of losartan and decrease the effects of its active metabolite.

Animal research shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of losartan (Cozaar) while decreasing plasma levels of losartan's active metabolite. This metabolite, which is around 10-fold more potent than losartan, is the result of cytochrome P450 (CYP) 2C9- and CYP3A4-mediated transformation of losartan. Additionally, in vitro research shows that quercetin may inhibit P-glycoprotein-mediated efflux of losartan from the intestines, resulting in increased absorption of losartan. These results suggest that concomitant use of quercetin and losartan might increase systemic exposure to losartan while also decreasing plasma concentrations of losartan's active and more potent metabolite.

Theoretically, concomitant use might decrease the levels and effects of midazolam.

A small clinical study in healthy volunteers shows that quercetin can increase the metabolism of midazolam, with a decrease in AUC of about 24%.

Theoretically, quercetin might increase the effects and adverse effects of mitoxantrone.
In vitro research shows that quercetin increases the intracellular accumulation and cytotoxicity of mitoxantrone, possibly through inhibition of breast cancer resistance protein (BCRP), of which mitoxantrone is a substrate. So far, this interaction has not been reported in humans.

Theoretically, concomitant use might increase the effects and adverse effects of OAT1 substrates.

In vitro research shows that quercetin is a strong non-competitive inhibitor of OAT1, with half-maximal inhibitory concentration (IC50) values less than 10 mcM. So far, this interaction has not been reported in humans.

Theoretically, concomitant use might increase the effects and adverse effects of OAT3 substrates.

In vitro research shows that quercetin is a strong non-competitive inhibitor of OAT3, with half-maximal inhibitory concentration (IC50) values as low as 0.75 mcM. So far, this interaction has not been reported in humans.

Theoretically, concomitant use might increase the effects and adverse effects of OATP substrates.

In vitro evidence shows that quercetin can inhibit organic anion-transporting peptide (OATP) 1B1-mediated uptake of estrone-3-sulfate and pravastatin. Furthermore, clinical research in healthy males shows that intake of quercetin along with pravastatin increases the AUC of pravastatin by 24%, prolongs its half-life by 14%, and decreases its apparent clearance by 18%, suggesting that quercetin modestly inhibits the uptake of pravastatin in hepatic cells.

Theoretically, concomitant use might alter the effects and adverse effects of P-glycoprotein substrates.

There is preliminary evidence that quercetin inhibits the gastrointestinal P-glycoprotein efflux pump, which might increase the bioavailability and serum levels of drugs transported by the pump. A small study in healthy volunteers reported that pretreatment with quercetin increased bioavailability and plasma levels after a single dose of cyclosporine (Neoral, Sandimmune). Also, two small studies have shown that quercetin might decrease the absorption of talinolol, a substrate transported by the gastrointestinal P-glycoprotein efflux pump. However, in another small study, several days of quercetin treatment did not significantly affect the pharmacokinetics of saquinavir (Invirase). The reason for these discrepancies is not entirely clear. Until more is known, use quercetin cautiously in combination with P-glycoprotein substrates.

Theoretically, concomitant use might increase the effects and adverse effects of pravastatin.
In vitro evidence shows that quercetin can inhibit OATP 1B1-mediated uptake of pravastatin. Also, preliminary clinical research in healthy males shows that intake of quercetin along with pravastatin increases the maximum concentration of pravastatin by 24%, prolongs its half-life by 14%, and decreases its apparent clearance by 18%, suggesting that quercetin modestly inhibits the uptake of pravastatin in hepatic cells.

Theoretically, quercetin might increase the effects and adverse effects of prazosin.
In vitro research shows that quercetin inhibits the transcellular efflux of prazosin, possibly through inhibition of breast cancer resistance protein (BCRP), of which prazosin is a substrate. BCRP is an ATP-binding cassette efflux transporter in the intestines, kidneys, and liver. So far, this interaction has not been reported in humans.

Theoretically, concomitant use might increase the effects and adverse effects of quetiapine.
Animal research shows that pretreatment with quercetin can increase plasma levels of quetiapine and prolong its clearance, possibly due to inhibition of cytochrome P450 3A4 (CYP3A4) by quercetin. Additionally, the brain-to-plasma ratio of quetiapine concentrations increased, possibly due to inhibition of P-glycoprotein at the blood-brain barrier. This interaction has not been reported in humans.

Theoretically, concomitant use might inhibit the effects of quinolone antibiotics.
In vitro, quercetin binds to the DNA gyrase site on bacteria, which may interfere with the activity of quinolone antibiotics.

Theoretically, quercetin might increase the effects and adverse effects of sulfasalazine.
Animal research shows that quercetin increases the maximum serum concentration (Cmax) and area under the curve (AUC) of sulfasalazine, possibly through inhibition of breast cancer resistance protein (BCRP), of which sulfasalazine is a substrate. So far, this interaction has not been reported in humans.

Theoretically, quercetin may increase the risk of bleeding if used with warfarin.
Animal and in vitro studies show that quercetin might increase serum levels of warfarin. Quercetin and warfarin have the same human serum albumin (HSA) binding site, and in vitro research shows that quercetin has stronger affinity for the HSA binding site and can theoretically displace warfarin, causing higher serum levels of warfarin. Animal research shows that taking quercetin for 2 weeks before initiating warfarin increases the maximum serum level of warfarin by 30%, the half-life by 10%, and the overall exposure by 63% when compared with control. Concomitant administration of quercetin and warfarin, without quercetin pre-treatment, also increased these measures, but to a lesser degree. Researchers theorize that inhibition of CYP3A4 by quercetin may explain these effects. So far, this interaction has not been reported in humans.

Theoretically, black pepper might increase the risk of bleeding when taken with antiplatelet or anticoagulant drugs.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit platelet aggregation. This has not been reported in humans.

Theoretically, black pepper might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research shows that piperine, a constituent of black pepper, can reduce blood glucose levels. Monitor blood glucose levels closely. Dose adjustments might be necessary.

Theoretically, black pepper might increase blood levels of atorvastatin.
Animal research shows that taking piperine, a constituent of black pepper, 35 mg/kg can increase the maximum serum concentration of atorvastatin three-fold. This has not been reported in humans.

Theoretically, black pepper might increase the effects and side effects of cyclosporine.
In vitro research shows that piperine, a constituent of black pepper, increases the bioavailability of cyclosporine. This has not been reported in humans.

Theoretically, black pepper might increase levels of drugs metabolized by CYP2D6.
In vitro research suggests that some constituents of black pepper inhibit CYP2D6. This has not been reported in humans.

Theoretically, black pepper might increase levels of drugs metabolized by CYP3A4.
In vitro research and pharmacokinetic simulation data suggest that piperine, a constituent of black pepper, as well as the pepper fruit seem to inhibit CYP3A4. This has not been reported in humans.

Theoretically, black pepper might increase blood levels of lithium due to its diuretic effects. The dose of lithium might need to be reduced.
Black pepper is thought to have diuretic properties.

Black pepper might increase blood levels of nevirapine.
Clinical research shows that piperine, a constituent of black pepper, increases the plasma concentration of nevirapine. However, no adverse effects were observed in this study.

Theoretically, black pepper might increase levels of P-glycoprotein substrates.
In vitro research shows that piperine, a constituent of black pepper, seems to inhibit P-glycoprotein.

Theoretically, black pepper might increase the sedative effects of pentobarbital.
Animal research shows that piperine, a constituent of black pepper, increases pentobarbital-induced sleeping time.

Black pepper might increase blood levels of phenytoin.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption, slow elimination, and increase levels of phenytoin. Taking a single dose of black pepper 1 gram along with phenytoin seems to double the serum concentration of phenytoin. Consuming a soup with black pepper providing piperine 44 mg/200 mL of soup along with phenytoin also seems to increase phenytoin levels when compared with consuming the same soup without black pepper.

Black pepper might increase blood levels of propranolol.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of propranolol.

Black pepper might increase blood levels of rifampin.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and serum levels of rifampin.

Black pepper might increase blood levels of theophylline.
Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of theophylline.

Theoretically, black pepper might increase the effects and side effects of amoxicillin.
Animal research shows that taking piperine, a constituent of black pepper, with amoxicillin increases plasma levels of amoxicillin. This has not been reported in humans.

Theoretically, black pepper might increase blood levels of carbamazepine, potentially increasing the effects and side effects of carbamazepine.
One clinical study in patients taking carbamazepine 300 mg or 500 mg twice daily shows that taking a single 20 mg dose of purified piperine, a constituent of black pepper, increases carbamazepine levels. Piperine may increase carbamazepine absorption by increasing blood flow to the GI tract, increasing the surface area of the small intestine, or inhibiting cytochrome P450 3A4 (CYP3A4) in the gut wall. Absorption was significantly increased by 7-10 mcg/mL/hour. The time to eliminate carbamazepine was also increased by 4-8 hours. Although carbamazepine levels were increased, this did not appear to increase side effects. In vitro research also shows that piperine can increase carbamazepine levels by 11% in a time-dependent manner.

Theoretically, black pepper might decrease levels and clinical effects of drugs metabolized by CYP1A2.
In vitro research suggests that black pepper induces CYP1A2. This has not been reported in humans.

Bitter orange might increase blood levels of midazolam.
One small clinical study shows that bitter orange juice can increase midazolam levels, likely through inhibition of cytochrome P450 3A4 (CYP3A4). Theoretically, bitter orange might increase the risk of midazolam-related adverse effects.

Theoretically, taking MAOIs with synephrine-containing bitter orange preparations might increase the hypertensive effects of synephrine, potentially leading to hypertensive crisis.
Bitter orange contains tyramine, octopamine, and synephrine, which are MAO substrates.

Theoretically, bitter orange might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Some clinical research shows that drinking a tea containing bitter orange and Indian snakeroot reduces fasting and postprandial glucose levels in patients with type 2 diabetes who are using antidiabetes drugs. However, it is unclear if these effects are due to bitter orange, Indian snakeroot, or the combination. An animal study also shows that p-synephrine in combination with gliclazide , a sulfonylurea, causes an additional 20% to 44% decrease in glucose levels when compared with gliclazide alone.

Bitter orange might increase blood pressure and heart rate when taken with caffeine.
Small clinical studies show that taking bitter orange in combination with caffeine can increase blood pressure and heart rate in otherwise healthy normotensive adults. Theoretically, this might increase the risk of serious cardiovascular adverse effects.

Bitter orange might affect colchicine levels.
Colchicine is a substrate of P-glycoprotein and cytochrome P450 3A4 (CYP3A4). Bitter orange has been reported to inhibit CYP3A4 and increase levels of CYP3A4 substrates. However, one small clinical study in healthy adults shows that drinking bitter orange juice 240 mL twice daily for 4 days and taking a single dose of colchicine 0.6 mg on the 4th day decreases colchicine peak serum levels by 24%, time to peak serum level by 1 hour, and overall exposure to colchicine by 20%. The clinical significance of this finding is unclear.

Bitter orange might increase levels of drugs metabolized by CYP3A4.
Small clinical studies suggest that single or multiple doses of freshly squeezed bitter orange juice 200-240 mL can inhibit CYP3A4 metabolism of drugs, causing increased drug levels and potentially increasing the risk of adverse effects. However, the extent of the effect of bitter orange on CYP3A4-mediated drug interactions is unknown. Some evidence suggests that bitter orange selectively inhibits intestinal CYP3A4, but not hepatic CYP3A4. Its effect on P-glycoprotein, which strongly overlaps with CYP3A4 interactions, is unclear. One small clinical study shows that drinking 8 ounces of freshly squeezed bitter orange juice has no effect on cyclosporine, which seems to be more dependent on hepatic CYP3A4 and P-glycoprotein than intestinal CYP3A4.

Bitter orange might increase blood levels of dextromethorphan.
One small clinical study shows that bitter orange juice increases dextromethorphan levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition. Theoretically, bitter orange might increase the risk for dextromethorphan-related adverse effects.

Bitter orange might increase blood levels of felodipine.
One small clinical study shows that bitter orange juice increases felodipine levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition. Theoretically, bitter orange might increase the risk for felodipine-related adverse effects.

Bitter orange might increase blood levels of indinavir.
One small clinical study shows that bitter orange juice slightly increases indinavir levels, but this effect is likely to be clinically insignificant. Bitter orange selectively inhibits intestinal cytochrome P450 3A4 (CYP3A4); however, the metabolism of indinavir seems to be more dependent on hepatic CYP3A4. The effect of bitter orange on other protease inhibitors has not been studied.

Theoretically, bitter orange might have an additive effect when combined with drugs that prolong the QT interval, potentially increasing the risk of ventricular arrhythmias.
One case report suggests that taking bitter orange in combination with other stimulants such as caffeine might prolong the QT interval in some patients.

Bitter orange juice might increase blood levels of sildenafil.
A small clinical study in healthy adult males shows that drinking freshly squeezed bitter orange juice 250 mL daily for 3 days and taking a single dose of sildenafil 50 mg on the 3rd day increases the peak plasma concentration of sildenafil by 18% and the overall exposure to sildenafil by 44%. Theoretically, this may be due to inhibition of cytochrome P450 3A4 by bitter orange.

Theoretically, bitter orange might increase the risk of hypertension and adverse cardiovascular effects when taken with stimulant drugs.
Bitter orange appears to have stimulant effects.

Theoretically, bitter orange might increase levels of drug metabolized by CYP2D6.
In vitro research shows that octopamine, a constituent of bitter orange, weakly inhibits CYP2D6 enzymes. This effect has not been reported in humans.

Theoretically, concurrent use might decrease the effectiveness of both agents.
Bacopa seems to inhibit acetylcholinesterase and might increase acetylcholine levels, which could counteract the effects of anticholinergic drugs. Similarly, anticholinergic drugs might counteract the cholinergic effects of bacopa.

Theoretically, bacopa might increase the effects and adverse effects of cevimeline.
In one case, a 58-year-old female taking cevimeline long-term for Sjogren syndrome experienced hyperhidrosis, malaise, nausea, and tachycardia shortly after taking a single dose of bacopa. Symptoms resolved after two days. Cevimeline is metabolized by cytochrome P450 (CYP) 2D6 and CYP3A4, and researchers theorize that bacopa may have inhibited these isoenzymes. However, it is unclear if bacopa causes clinically significant inhibition of either CYP2D6 or CYP3A4.

Theoretically, concurrent use of bacopa with other cholinergic drugs might have additive effects.
Bacopa seems to inhibit acetylcholinesterase and might increase acetylcholine levels. Theoretically, this could result in additive cholinergic effects when used with cholinergic drugs.

Theoretically, bacopa might increase the levels and adverse effects of CYP1A2 substrates.
Research on the effects of bacopa extracts on CYP1A2 enzymes is conflicting. Some in vitro evidence shows that bacopa extract can moderately and non-competitively inhibit CYP1A2, while other in vitro evidence suggests that any effect is unlikely to be clinically significant.

Theoretically, bacopa might increase the levels and adverse effects of CYP2C19 substrates.
In vitro evidence suggests that bacopa extract can moderately and non-competitively inhibit CYP2C19 enzymes. It is not known whether this is clinically significant.

Theoretically, bacopa might increase the levels and adverse effects of CYP2C9 substrates.
Research on the effect of bacopa extracts on CYP2C9 enzymes is conflicting. Some in vitro evidence suggests that bacopa extract can moderately and non-competitively inhibit CYP2C9, while other in vitro evidence suggests that any effect is unlikely to be clinically significant.

Theoretically, bacopa might increase the levels and adverse effects of CYP3A4 substrates.
Research on the effects of bacopa extracts on CYP3A4 enzymes is conflicting. Some in vitro evidence suggests that bacopa extract can moderately and competitively inhibit CYP3A4, while other in vitro evidence suggests that any effect is unlikely to be clinically significant.

Theoretically, bacopa might have additive effects when used with thyroid hormone.
Animal research suggests that bacopa increases thyroxine (T4) levels in mice by about 40%.

Theoretically, higenamine might increase the risk of bleeding or bruising when taken with anticoagulant/antiplatelet drugs.
Animal research shows that higenamine inhibits platelet aggregation and reduces the size of thrombus formation.

Theoretically, higenamine might increase the levels and clinical effects of drugs metabolized by CYP2D6.
In vitro research shows that higenamine inhibits CYP2D6 enzymes. However, this effect has not been reported in humans.

Theoretically, higenamine might increase the levels and clinical effects drugs metabolized by CYP3A4.
In vitro research shows that higenamine inhibits CYP3A4 enzymes by 21%. However, this effect has not been reported in humans.

Theoretically, higenamine might increase the risk of cardiovascular toxicity when taken with stimulant drugs.
Higenamine has stimulant effects due to agonist activity at beta2-adrenoreceptors. In cardiac muscle, higenamine appears to have a positive inotropic effect and increase heart rate. However, it does not appear to increase blood pressure.

Theoretically, the positive inotropic effects of higenamine might be reduced by propranolol.
Animal research shows that higenamine has a positive inotropic effect on the heart, and administering propranolol appears to block this cardiac effect. In animals, propranolol also appears to inhibit corpus cavernosum relaxation induced by higenamine.

Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Use of ephedrine with caffeine can increase the risk of stimulatory adverse effects. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death.

Theoretically, caffeine might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Some evidence shows that caffeine is a competitive inhibitor of adenosine and can reduce the vasodilatory effects of adenosine in humans. However, other research shows that caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Theoretically, caffeine may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Caffeine is reported to have antiplatelet activity. Theoretically, it might increase the risk of bleeding when used concomitantly with these agents; however, this interaction has not been reported in humans.

Theoretically, large amounts of caffeine might increase the cardiac inotropic effects of beta-agonists.

Theoretically, caffeine might reduce the effects of carbamazepine and increase the risk for convulsions.
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. 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.

Theoretically, cimetidine might increase the levels and adverse effects of caffeine.
Cimetidine decreases the rate of caffeine clearance by 31% to 42%.

Caffeine might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
Caffeine might increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg per day inhibit clozapine metabolism. Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Although researchers speculate that caffeine might inhibit CYP1A2, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients more sensitive to an interaction between clozapine and caffeine. In one case report, severe, life-threatening clozapine toxicity and multiorgan system failure occurred in a patient with schizophrenia stabilized on clozapine who consumed caffeine 600 mg daily.

Theoretically, caffeine might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Caffeine inhibits dipyridamole-induced vasodilation. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Theoretically, disulfiram use might increase the levels and adverse effects of caffeine.
Disulfiram decreases the rate of caffeine clearance.

Theoretically, using caffeine with diuretic drugs might increase the risk of hypokalemia.
Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.

Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Estrogen inhibits caffeine metabolism.

Theoretically, caffeine might reduce the effects of ethosuximide and increase the risk for convulsions.
Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide. However, this effect has not been reported in humans.

Theoretically, caffeine might reduce the effects of felbamate and increase the risk for convulsions.
Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate. However, this effect has not been reported in humans.

Theoretically, caffeine might increase the levels and adverse effects of flutamide.
In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide. However, this effect has not been reported in humans.

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Fluvoxamine reduces caffeine metabolism.

Abrupt caffeine withdrawal might increase the levels and adverse effects of lithium.
Caffeine has diuretic activity. When abruptly discontinued, caffeine may alter the clearance of lithium. There are two case reports of lithium tremor that worsened upon abrupt coffee withdrawal and 6 case reports of elevated serum lithium levels after reducing or eliminating caffeine intake. In one case, a male with schizoaffective disorder stabilized on lithium had an elevated lithium level after reducing his caffeine intake by 87%. At a later date, he increased his caffeine intake by 6-fold, resulting in a subtherapeutic lithium level and a recurrence of psychiatric symptoms.

Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies. Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis. In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension. Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

Theoretically, concomitant use might increase the risk of hypertension.
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.

Theoretically, caffeine might decrease the effects of pentobarbital.
Caffeine might negate the hypnotic effects of pentobarbital.

Theoretically, caffeine might reduce the effects of phenobarbital and increase the risk for convulsions.
Animal research suggests that caffeine can decrease the anticonvulsant activity of phenobarbital. However, the exact mechanism of this interaction is unclear.

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure. Phenylpropanolamine also seems to increase caffeine serum levels.

Theoretically, caffeine might reduce the effects of phenytoin and increase the risk for convulsions.
Animal research suggests that caffeine can decrease the anticonvulsant activity of phenytoin. The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

Theoretically, caffeine might increase the levels and clinical effects of pioglitazone.
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. However, the exact mechanism of this interaction is unclear.

Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.
Quinolones (also called fluoroquinolones) can decrease caffeine clearance by inhibiting cytochrome P450 1A2 (CYP1A2) enzyme.

Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce the metabolism of one or both agents.

Theoretically, concomitant use might increase the risk for stimulant adverse effects.
Guarana contains caffeine. Use of ephedrine with caffeine can increase the risk of stimulatory adverse effects. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death.

Theoretically, guarana might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Guarana contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Theoretically, guarana may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro and animal research suggests that guarana extract can inhibit platelet aggregation. This effect may be due to the caffeine in guarana, which is also reported to have antiplatelet activity. This interaction has not been reported in humans.

Theoretically, concomitant use might increase the clinical effects of beta-adrenergic agonists.
Guarana contains caffeine. Theoretically, concomitant use of large amounts of caffeine might increase cardiac inotropic effects of beta-agonists.

Theoretically, guarana might reduce the effects of carbamazepine and increase the risk for convulsions.
Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when given to animals in doses above 400 mg/kg. 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 two-fold in healthy individuals.

Theoretically, concomitant use might increase the effects and adverse effects of caffeine in guarana.
Guarana contains caffeine. Cimetidine decreases the rate of caffeine clearance by 31% to 42%.

Theoretically, guarana might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
Guarana contains caffeine. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg per day inhibit clozapine metabolism. 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 more sensitive to the interaction between clozapine and caffeine.

Theoretically, guarana might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Guarana contains caffeine. Caffeine might inhibit dipyridamole-induced vasodilation. It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests. Methylxanthines appear more likely to interfere with dipyridamole than adenosine-induced stress testing.

Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
In human research, disulfiram decreases the clearance and increases the half-life of caffeine.

Theoretically, using guarana with diuretic drugs might increase the risk of hypokalemia.
Guarana contains caffeine. Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also lower potassium levels.

Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Estrogen inhibits caffeine metabolism.

Theoretically, guarana might reduce the effects of ethosuximide and increase the risk for convulsions.
Guarana contains caffeine. Animal research shows that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide. This effect has not been observed in humans.

Theoretically, guarana might reduce the effects of felbamate and increase the risk for convulsions.
Guarana contains caffeine. Animal research shows that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate. This effect has not been observed in humans.

Theoretically, guarana might increase the levels and adverse effects of flutamide.
Guarana contains caffeine. In vitro evidence shows that caffeine can inhibit the metabolism of flutamide. However, this effect has not been reported in humans.

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Guarana contains caffeine. Fluvoxamine reduces caffeine metabolism.

Theoretically, abrupt guarana withdrawal might increase the levels and adverse effects of lithium.
Guarana contains caffeine. Theoretically, abrupt caffeine withdrawal might increase serum lithium levels. There are two case reports of lithium tremor that worsened upon abrupt coffee withdrawal.

Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Guarana contains caffeine. Caffeine has been shown to inhibit MAO-A and -B in laboratory studies. Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis. In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension. Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

Theoretically, concomitant use might increase the risk of hypertension.
Guarana 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.

Theoretically, guarana might decrease the effects of pentobarbital.
Guarana contains caffeine. In vivo evidence suggests that caffeine can negate the hypnotic effects of pentobarbital in humans. However, animal research suggests that guarana does not alter the hypnotic effect of pentobarbital.

Theoretically, guarana might reduce the effects of phenobarbital and increase the risk for convulsions.
Guarana contains caffeine. Animal research shows that caffeine can decrease the anticonvulsant activity of phenobarbital. The exact mechanism of this interaction is unclear.

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Guarana contains caffeine. Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure. Phenylpropanolamine also seems to increase caffeine serum levels.

Theoretically, guarana might reduce the effects of phenytoin and increase the risk for convulsions.
Guarana contains caffeine. Animal research shows that caffeine can decrease the anticonvulsant activity of phenytoin. The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

Theoretically, guarana might increase the levels and clinical effects of pioglitazone.
Guarana 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. However, the exact mechanism of this interaction is unclear.

Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
Guarana contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce the metabolism of one or both agents.

Theoretically, concomitant use might increase stimulant adverse effects.
Guarana 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.

Theoretically, concomitant use might increase the risk of stimulant adverse effects.
Coffee contains caffeine. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death. Tell patients to avoid taking caffeine with ephedrine and other stimulants.

Theoretically, coffee might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Coffee contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine. It is recommended that methylxanthines such as caffeine, as well as methylxanthine-containing products, be stopped 24 hours prior to pharmacological stress tests. However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Coffee reduces alendronate bioavailability.
Separate coffee ingestion and alendronate administration by two hours. Coffee reduces alendronate bioavailability by 60%.

Theoretically, coffee may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Coffee contains caffeine. Caffeine is reported to have antiplatelet activity. Theoretically, the caffeine in coffee might increase the risk of bleeding when used concomitantly with these agents. However, this interaction has not been reported in humans. There is some evidence that caffeinated coffee might increase the fibrinolytic activity in blood.

Theoretically, concomitant use of large amounts of coffee might increase cardiac inotropic effects of beta-agonists.
Coffee contains caffeine. Caffeine can increase cardiac inotropic effects of beta-agonists.

Theoretically, cimetidine might increase the effects and adverse effects of caffeine in coffee.
Coffee contains caffeine. Cimetidine can reduce caffeine clearance by 31% to 42%.

Theoretically, coffee might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
Coffee contains caffeine. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg daily inhibit clozapine metabolism. 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.

Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in coffee.
Coffee contains caffeine. Oral contraceptive drugs can decrease caffeine clearance by 40% to 65%.

Theoretically, coffee might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Coffee contains caffeine. Caffeine is a methylxyanthine that may inhibit dipyridamole-induced vasodilation. It is recommended that methylxanthines such as caffeine, as well as methylxanthine-containing products such as coffee, be stopped 24 hours prior to pharmacological stress tests. Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
Coffee contains caffeine. In human research, disulfiram decreases the clearance and increases the half-life of caffeine.

Theoretically, concomitant use might increase the risk of hypokalemia.
Coffee contains caffeine. Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.

Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Coffee contains caffeine. Estrogen inhibits caffeine metabolism.

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Coffee contains caffeine. Fluvoxamine reduces caffeine metabolism.

Coffee consumption can decrease the levels and clinical effects of lamotrigine.
A pharmacokinetic study in patients taking lamotrigine shows that consumption of coffee, both caffeinated and decaffeinated, can decrease the area under the concentration-time curve (AUC) and the peak plasma level (Cmax) of lamotrigine. Each additional cup of coffee reduced the AUC and Cmax by 4% and 3%, respectively. It is unclear whether this interaction is due to induction of lamotrigine metabolism or inhibition of lamotrigine absorption.

Coffee can reduce the absorption of levothyroxine.
In some patients, coffee can reduce levothyroxine absorption, possibly through the formation of non-absorbable complexes. A pharmacokinetic study in these patients found that 25-30 mL of espresso coffee consumed with levothyroxine tablets delayed the time to peak plasma levels by 38-43 minutes, reduced the peak plasma level (Cmax) by 19% to 36%, and reduced the area under the curve (AUC) by 27% to 36%. Coffee consumed one hour after levothyroxine did not affect absorption. It is not known whether this interaction occurs with other types of coffee. Tell patients to avoid drinking coffee at the same time that they take their levothyroxine, and for up to an hour afterwards.

Theoretically, abrupt coffee withdrawal might increase the levels and adverse effects of lithium.
Coffee contains caffeine. Abrupt caffeine withdrawal can increase serum lithium levels. Two cases of lithium tremor that worsened with abrupt coffee withdrawal have been reported. There is also one case of a 2.8-fold increase in blood lithium levels after a patient taking lithium reduced his coffee consumption from 13-20 cups daily to 10 cups daily.

Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Coffee contains caffeine. Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies. Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis. In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension. Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

Theoretically, concomitant use might increase the risk of hypertension.
Coffee 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.

Theoretically, coffee might reduce the effects of pentobarbital.
Coffee contains caffeine. Theoretically, caffeine might negate the hypnotic effects of pentobarbital.

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Coffee contains caffeine. Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure. Phenylpropanolamine also seems to increase caffeine serum levels.

Theoretically, coffee might increase the levels and clinical effects of pioglitazone.
Coffee 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. However, the exact mechanism of this interaction is unclear.

Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.
Coffee contains caffeine. Concomitant use of caffeine and quinolones can decrease caffeine clearance and increase effects and risk of adverse effects.

Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.
Coffee contains caffeine. Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce metabolism of one or both agents.