To the editor: The editorial by McCarthy (1) comparing ranitidine and cimetidine is misleading in several aspects. His attempt to represent the drugs as similar has many flaws.
First, he questions whether patients whose treatment fails with either drug might be effectively managed with the other drug. In fact, ranitidine does supress gastric hypersecretion in some patients who are resistent to cimetidine (2, 3). Second, the drug interactions associated with ranitidine are rare and not of the same magnitude as those seen with cimetidine, as a rule (4). This difference is due to the lesser effect of ranitidine on cytochrome-P450-mediated