Skip to Content

Blood Thinner Medications and Alcohol

Written by L. Anderson, PharmD on Nov 7, 2017

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 interactions. Patients receiving warfarin should avoid alcohol intoxication, but the available information suggests modest alcohol intake (1 to 2 drinks/day) has little effect on warfarin response, but this can be variable. Avoid alcohol and warfarin unless 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 either lead to an elevated risk of bleeding or a decreased warfarin effect. Liver disease may alter 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 oral anticoagulants like warfarin and can lower the effectiveness of warfarin, increasing the risk of a clot, a heart attack or stroke.
  • 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, nosebleeds, blood in your urine or stools, black stools, headache, dizziness, or weakness.

The newer direct-acting oral anticoagulants such as:

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.

Types of Drug Interactions With Alcohol

Further information

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