What Are the Risks of Mixing Alcohol and Aspirin?

Using aspirin as a prophylactic treatment, taken at the beginning a drinking session, is a common practice used to avoid an alcohol-induced hangover. Mixing alcohol and aspirin, however, carries some risk. Both substances can be toxic to the liver, and using them together during the same period of time can overload the liver and cause hepatic damage. In addition, research shows that aspirin may hinder the body’s ability to break down alcohol, which can lead to unintended levels of alcohol intoxication. There is also increased risk of internal bleeding when alcohol and aspirin are present in the gastrointestinal (GI) tract at the same time.

Aspirin, alcohol, and other orally-active drugs are absorbed first through the lining of the stomach, a sensitive membrane that is composed of mucosa. Alcohol and aspirin are both known to irritate the stomach’s mucousal lining, but when used alone and in appropriate doses, they do not generally cause significant damage. In fact, many people take aspirin daily to fight chronic pain or to prevent a heart attack. When both alcohol and aspirin are taken together, however, the risk of damaging the GI tract increases significantly. This damage can cause chronic bleeding ulcers and other instances of internal bleeding.

In addition to the GI bleeding that may occur because of irritation to the gastric mucosa, other complications may arise because of the pharmacological characteristics of aspirin. Daily aspirin regimens that are used to treat diseases related to the obstructed flow of blood, like stroke and heart attack, are prescribed because aspirin is a blood thinner. It prevents the formation of blood clots and prevents plaque buildup on artery walls. The anticoagulant properties of aspirin can be devastating, however, because if GI bleeding does occur from the combination, aspirin can cause the bleed to progress to a life-threatening hemorrhage. This side effect is usually seen if the person has been taking aspirin every day, but can also occur after only one dose.

Before being absorbed by the stomach lining, alcohol is broken down while still in the stomach by an enzyme, alcohol dehydrogenase (ADH). Aspirin interferes with gastric ADH production, and taking both substances together can lead to an unexpected rise in blood alcohol content (BAC) because alcohol is not metabolized properly when aspirin is present. While the increase may not be statistically significant, a person may not be aware that his or her tolerance for alcohol has been diminished, which can lead to an incorrect assessment of sobriety.