Does Alcohol Thin Your Blood?

Mature woman at desk reading book by glass of red wine
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Drinking alcohol has effects on blood coagulation. If you drink a moderate amount of alcohol—defined as one drink per day—it may have the benefit of acting as a blood thinner and be protective against clotting in clogged arteries, like aspirin. At the same time, thinning the blood can hasten bleeding from injured arteries, increasing the risk of bleeding strokes.

It also will interact with prescription anticoagulants such as Coumadin (warfarin).

Moderate drinking is a balancing act of sorts. If you drink exactly the right amount to be "moderate" it may be better in some health effects than not drinking at all, But if you drink just a tad over the guidelines for moderate, it is much more dangerous than not drinking at all. It's called the J-curve. Even if you hit the sweet spot, moderate drinking is a two-edged sword with some beneficial effects and some negative ones.

Precautions Against Drinking Alcohol While Taking Blood Thinners

You should abstain from alcohol while taking anticoagulant blood thinners such as Coumadin (warfarin) as the blood-thinning effects of alcohol can interact with those of the prescribed drugs. It will be more difficult for your healthcare providers to determine the correct dosage for the prescribed blood thinner if you also drink alcohol.

As you will be placed on blood thinners to prevent a significant health threat, such as a deep venous thrombosis, it's best not to take the risk and have an alcoholic beverage.

Also, consider the other prescriptions that you take. Sometimes they interact with blood thinners and alcohol. Follow the precautions and refrain from drinking if that is recommended.

Don't Substitute Alcohol for Prescription Blood Thinners

Likewise, if you need anticoagulation to reduce a health risk, it is unwise to think that drinking alcohol is a substitute for prescribed blood thinners. When your doctor prescribes an anticoagulant such as Coumadin, you will also have your blood tested regularly to ensure you are getting just the right amount of blood thinning. Too little and you aren't protected. Too much and you risk bleeding.

Contrasting Effects of Alcohol on Coagulation

Some studies have shown that moderate drinkers tend to have lower rates of heart disease, but higher rates of bleeding-type strokes than abstainers. "The contrasting effects of alcohol are similar to the effects of blood thinners like aspirin, which clearly prevent heart attacks but at the expense of some additional bleeding strokes," said Kenneth J. Mukamal, a researcher with numerous papers on the effects of alcohol on coagulation and cardiovascular risks.

No Reason to Start Drinking

There is increasing skepticism among researchers that moderate drinking has protective health effects for heart disease, according to the CDC. The bottom line is, although moderate drinking may have some health benefits, there is risk involved, too.

If you don't drink, the risks of developing other problems associated with alcohol may be too great to begin drinking for its limited benefits.

Sources:

Fact Sheets - Moderate Drinking. CDC. https://www.cdc.gov/alcohol/fact-sheets/alcohol-use.htm

Larsson SC, Wallin A, Wolk A, Markus HS. Differing association of alcohol consumption with different stroke types: a systematic review and meta-analysis. BMC Medicine. 2016;14(1). doi:10.1186/s12916-016-0721-4.

Taking Warfarin (Coumadin) NIH MedlinePlus. https://medlineplus.gov/ency/patientinstructions/000292.htm