THE POTENTIAL availability of histamine2-receptor antagonists (or H2 blockers) on an over-the-counter (OTC) basis has raised more questions than we currently have answers for. In this article, I review the mechanism of action and current prescription uses of this family of drugs and consider what we now know about its likely OTC use. After this review of H2 blockers, I discuss arguments in favor of and against the OTC availability.
In 1977, soon after the development of a family of H2 blockers by Black, cimetidine became the first H2 blocker to be marketed in the United States. Cimetidine was initially approved by the Food and Drug Administration (FDA) for the acute healing of duodenal ulcer, at a dose of 300 mg four times daily, and for treatment of acid hypersecretory states, such as Zollinger-Ellison syndrome, in which much higher doses than 1200 mg/d were