Pomegranate - Warfarin Interaction

Interaction Details

Warfarin is classified as belonging to the following category: Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, pomegranate might increase levels of drugs metabolized by CYP2C9.
Some animal and in vitro research shows that pomegranate juice inhibits intestinal, but not hepatic, CYP2C9 isoenzyme activity. However, clinical research shows that neither pomegranate juice nor pomegranate extract have a significant effect on CYP2C9 activity in humans.

Interaction Rating

Likelihood of Occurrence

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

References

• Nagata M, Hidaka M, Sekiya H, et al. Effects of pomegranate juice on human cytochrome P450 2C9 and tolbutamide pharmacokinetics in rats. Drug Metab Dispos 2007;35:302-5.
• Hanley MJ, Masse G, Harmatz JS, et al. Pomegranate juice and pomegranate extract do not impair oral clearance of flurbiprofen in human volunteers: divergence from in vitro results. Clin Pharmacol Ther 2012;92(5):651-7.

Interaction Details

Warfarin is classified as belonging to the following category: Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, pomegranate might increase levels of drugs metabolized by CYP3A4, but most research suggests this interaction is unlikely to be clinically significant.
Pomegranate contains several polyphenols that have individually been shown to inhibit CYP3A4. However, there is contradictory evidence about the effect of whole pomegranate juice on CYP3A4 activity. In vitro, pomegranate juice significantly inhibits the CYP3A4 enzyme, with comparable inhibition to grapefruit juice. In an animal model, pomegranate juice inhibits CYP3A4 metabolism of carbamazepine and increases levels of carbamazepine by 1.5 times; however, in human volunteers, drinking a single glass of pomegranate juice 240 mL or taking 200 mL daily for 2 weeks does not significantly affect levels of the CYP3A4 substrate midazolam after oral or intravenous administration. Another study in healthy volunteers shows that consuming pomegranate juice 300 mL three times daily for three days also does not significantly affect levels of simvastatin, a CYP3A4 substrate This suggests that pomegranate is unlikely to significantly affect levels of CYP3A4 substrates in humans.

Interaction Rating

Likelihood of Occurrence

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

References

• Hidaka M, Okumura M, Fujita K, et al. Effects of pomegranate juice on human cytochrome p450 3A (CYP3A) and carbamazepine pharmacokinetics in rats. Drug Metab Dispos 2005;33:644-8.
• Farkas D, Oleson LE, Zhao Y, et al. Pomegranate juice does not impair clearance of oral or intravenous midazolam, a probe for cytochrome P450-3A activity: comparison with grapefruit juice. J Clin Pharmacol 2007;47:286-94.
• Yeo C, Shon J, Liu K, et al. The effects of pomegranate juice on the pharmacokinetics of simvastatin in healthy Korean subjects (PI-63). Clin Pharmacol Ther 2006;79:23.
• Farkas D, Greenblatt DJ. Influence of fruit juices on drug disposition: discrepancies between in vitro and clinical studies. Expert Opin Drug Metab Toxicol 2008;4:381-93.
• Misaka S, Nakamura R, Uchida S, et al. Effect of 2 weeks' consumption of pomegranate juice on the pharmacokinetics of a single dose of midazolam: an open-label, randomized, single-center, 2-period crossover study in healthy Japanese volunteers. Clin Ther
• Park SJ, Yeo CW, Shim EJ, et al. Pomegranate juice does not affect the disposition of simvastatin in healthy subjects. Eur J Drug Metab Pharmacokinet 2016;41(4):339-44.

Interaction Details

Warfarin is classified as belonging to the following category: Warfarin (Coumadin)

Theoretically, pomegranate might increase warfarin levels and increase the risk of bleeding. Also, discontinuing regular consumption of pomegranate juice might decrease warfarin levels.
In one case report, a patient had a stable, therapeutic bleeding time, as measured by international normalized ratio (INR), while taking warfarin in combination with pomegranate juice 2-3 times per week. The patient became subtherapeutic within about 10 days after discontinuing pomegranate juice, which required a warfarin dose increase. In another case report, a patient with a stable INR for over one year presented with an INR of 14. The patient noted no changes to medications or diet but did report consuming around 3 liters of pomegranate juice over the previous week. The patient's INR stabilized upon moderation of pomegranate juice consumption. The mechanism of this potential interaction is unclear.

Interaction Rating

Likelihood of Occurrence

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists

References

• Komperda KE. Potential interaction between pomegranate juice and warfarin. Pharmacotherapy 2009;29:1002-6.
• Jarvis S, Li C, Bogle RG. Possible interaction between pomegranate juice and warfarin. Emerg Med J 2010;27:74-5.

Warfarin Overview

• Warfarin is used to prevent blood clots from forming or growing larger in your blood and blood vessels. It is prescribed for people with certain types of irregular heartbeat, people with prosthetic (replacement or mechanical) heart valves, and people who have suffered a heart attack. Warfarin is also used to treat or prevent venous thrombosis (swelling and blood clot in a vein) and pulmonary embolism (a blood clot in the lung). Warfarin is in a class of medications called anticoagulants ('blood thinners'). It works by decreasing the clotting ability of the blood.

Pomegranate - More Interactions

Pomegranate interacts with 897 drugs

Interaction Rating Key

These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.