Effect of common over-the-counter medications on blood alcohol levels

To assess the clinical and legal significance of the potential pharmacokinetic interaction between common over-the-counter (OTC) medications and alcohol that may result in increased blood alcohol levels (BALs).

A MEDLINE search (1966-February 2000) of English-language articles was performed using the terms aspirin, acetaminophen, histamine (H2)-receptor antagonist, ethanol, and blood alcohol level and then supplemented by a bibliographic review of relevant articles.

Two H2-receptor antagonist studies using methodologies representative of other published trials and a meta-analysis of 24 H2-receptor antagonist trials were chosen for detailed review. All identified studies examining aspirin and acetaminophen were addressed.

More than 30 studies have examined the potential interaction between OTC drugs and blood alcohol. Because this issue has important medical and legal implications for patients, prescribing physicians, and pharmaceutical manufacturers, a critical analysis of the literature addressing this potential interaction is presented.

Numerous factors arguing against a clinically significant interaction were identified. First, data from the relevant studies cannot be extrapolated to the general population because of the multitude of variables that determine an individual's BAL. Also, a publication bias for small studies (< or = 10 subjects) finding a statistically significant increase in peak BAL was observed. In addition, study results supporting an increase in BAL were often irreproducible when these trials were repeated under similar conditions. Finally, although some studies detected statistically significant increases in peak BAL, these changes were often clinically irrelevant.