A new form of antihistamine--the H2-receptor antagonist.

A new group of drugs, the histamine2 (H2)-receptor antagonists, act on receptors in the stomach to reduce acid secretion when this is stimulated by histamine, pentagastrin, the vagus nerve or food. The reduction in acid secretion is profound and may approach the degree of reduction brought about by gastric surgery. The H2-receptor antagonist metiamide, administered orally, has been used successfully in the treatment of duodenal ulcer and the Zollinger-Ellison syndrome, but it has been shown to cause agranulocytosis. Trials are in process with an analogue, cimetidine (Tagamet, SKF), which has a different chemical structure from metiamide and has not caused haematological changes in animals or man. These drugs offer the prospect of successful medical management of duodenal ulcer, while a study of their effects on H2-receptors elsewhere in the body may reveal other therapeutic benefits.