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Blood Thinner Drugs and Alcohol: A Dangerous Mix?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Nov 8, 2019.

Warfarin Interactions With Alcohol

Warfarin (Coumadin) is a commonly used blood thinner (a coumarin oral anticoagulant). It is used to prevent or treat blood clots in veins, arteries, or the heart, which can reduce the risk of stroke, heart attack, or other serious conditions. It can also keep an existing clot from getting larger. Patients with a history of atrial fibrillation (AFib), peripheral artery disease (PAD), heart attack, or knee or hip surgeries at risk for venous thromboembolism (VTE) may use an anticoagulant.

  • Combining alcohol and blood thinner medications such as warfarin can lead to drug interactions. Patients receiving warfarin should avoid acute alcohol intoxication, but the available information suggests modest alcohol intake (1 to 2 drinks/day) has little effect on warfarin response. It's probably wise to avoid alcohol and warfarin until approved by your doctor. If you chronically drink alcohol or have active liver disease, alert your prescriber.
  • Alcohol and warfarin side effects: When warfarin is combined with alcohol, the effects of warfarin can be altered and may lead to a greater risk of bleeding or a decreased warfarin effect. Liver disease may change these effects, too.
    • Acutely drinking large amounts of alcohol (binge drinking) can decrease the metabolism (breakdown) of oral anticoagulants and increase the bleeding risk.
    • On the other hand, excessive daily alcohol use increases the metabolism of warfarin and can lower its effectiveness, increasing the risk of a clot, a heart attack or stroke.
    • The antiplatelet effect of alcohol may increase bleeding risk without effects on INR, a measure of warfarin effect. Platelets are important blood cells that help your body to form clots when bleeding. An antiplatelet effect can stop blood clots from forming.
  • Call your doctor promptly if you have any unusual bleeding or bruising, vomiting, prolonged bleeding from cuts, increased menstrual flow, bleeding of gums from brushing your teeth, nosebleeds, blood in your urine or stools, black stools, headache, dizziness, or weakness.

The newer direct-acting oral anticoagulants (DOACs) do not have alcohol-drug interactions listed in their product labeling. However, if you consume large amounts of alcohol at one time or drink alcohol on a daily basis, be sure to discuss this with your doctor. Heavy alcohol use may increase the risk of a stomach ulcer or bleeding, and this can be worsened by an anticoagulant. In addition, some direct-acting oral anticoagulants are broken down in the liver; if you have alcohol-induced liver disease, tell your healthcare provider. 

Table 1: Direct-acting oral anticoagulants

Generic name Brand example
apixaban Eliquis
rivaroxaban Xarelto
edoxaban Savaysa
dabigatran Pradaxa

Types of Drug Interactions With Alcohol

Sources

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  • Weathermon R, Crabb DW. Alcohol and medication interactions. Alcohol Res Health. 1999;23(1):40–54. PMID: 10890797.
  • Warfarin Sodium. ASHP Monograph. Oct. 2019. Drugs.com. Accessed Nov. 8, 2019 at https://www.drugs.com/monograph/warfarin-sodium.html
  • Havrda DE, Mai T, Chonlahan J et al. Enhanced antithrombotic effect of warfarin associated with low-dose alcohol consumption. Pharmacotherapy. 2005; 25(2):303-7. Accessed Nov. 8, 2019 at http://www.ncbi.nlm.nih.gov/pubmed/15767245
  • Mukamal KJ, Smith CC, Karlamangla AS et al. Moderate alcohol consumption and safety of lovastatin and warfarin among men: the Post-Coronary Artery Bypass Graft Trial. Am J Med. 2006; 119:434-40. Accessed Nov. 8, 2019 at https://www.ncbi.nlm.nih.gov/pubmed/16651056
  • Breslow RA, Dong C, White A. Prevalence of Alcohol-Interactive Prescription Medication Use Among Current Drinkers: United States, 1999 to 2010. Alcohol Clin Exp Res. 2015; 39:371-79. Accessed Nov. 10, 2019.
  • Hansten PD, Horn JR. Top 100 Drug Interactions 2017; p. 8. A Guide to Patient Management. H&H Publications, Freeland, WA.
  • Alcohol Facts & Statistics. National Institute on Alcohol and Abuse and Alcoholism (NIAAA). National Institutes of Health (NIH). Accessed Nov. 10, 2019 at https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/alcohol-facts-and-statistics

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.