Soy - Coumadin (Warfarin Sodium) Interaction

Interaction Details

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

Soy might modestly induce CYP2C9 enzymes. However, this effect does not seem to be clinically significant.
In vitro research suggests that an unhydrolyzed soy extract might induce CYP2C9. However, the significance of this interaction is likely minimal. In healthy females taking a specific extract of soy (Genistein Soy Complex, Source Naturals), blood levels of losartan, a CYP2C9 substrate, were not significantly affected.

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

• Wang G, Xiao CQ, Li Z, et al. Effect of soy extract administration on losartan pharmacokinetics in healthy female volunteers. Ann Pharmacother 2009;43:1045-9.

Interaction Details

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

Theoretically, soy might interfere with the effects of warfarin.
Soy milk has been reported to decrease the international normalized ratio (INR) in a patient taking warfarin. The mechanism of this interaction is not known. However, animal and in vitro research suggests that soy may also inhibit platelet aggregation. Dosing adjustments for warfarin may be necessary.

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

• Anthony MS. Soy and cardiovascular disease: Cholesterol lowering and beyond. J Nutr 2000;130:662S-3S.
• Cambria-Kiely JA. Effect of soy milk on warfarin efficacy. Ann Pharmacother 2002;36:1893-6..

Warfarin Sodium 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.

Soy - More Interactions

Soy interacts with 602 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.