To the Editor.
—The article by DiPadova et al1 reported that ranitidine and cimetidine, but not famotidine, increase blood alcohol concentrations when 0.3 g/kg ethanol is administered to men in the morning following breakfast. We have several comments and questions about this article.First, ethanol concentrations were measured by three different analytical methods (breath analyzer, plasma enzymatic assay, and plasma gas chromatography) in different subjects. While the authors imply that the methods gave virtually identical results, no further information was presented. Cross-validation of results is essential to exclude systematic differences between such diverse methods. We note that in previous articles published by Frezza et al2 and Caballeria et al3 on ethanol presystemic clearance, only one method was used in each study, rather than three methods.Second, the three assay methods are reported as blood alcohol concentrations. However, blood was not analyzed, and no conversion from plasma to