ATC Group: A02BA H2-receptor antagonists

Cimetidine is a histamine H₂-receptor antagonist which rapidly inhibits both basal and stimulated gastric secretion of acid and reduces pepsin output. It is a reversible, competitive antagonist, and is used as an anti-ulcer drug.

Famotidine is a potent competitive H₂-receptor antagonist. Famotidine has a rapid onset of action and, at the recommended doses, has a long duration of action and is highly effective at relatively low blood concentrations.

Nizatidine is a potent, selective, competitive and fully reversible histamine H₂-receptor antagonist. Nizatidine significantly decreased basal and stimulated gastric acid and pepsin concentration, in addition to the volume of gastric secretion.

Ranitidine is a specific rapidly acting histamine H₂-antagonist. It inhibits basal and stimulated secretion of gastric acid, reducing both the volume and the acid and pepsin content of the secretion. Ranitidine has a relatively long duration of action and so a single 150 mg dose effectively suppresses gastric acid secretion for twelve hours.

Roxatidine is a competitive histamine H2 receptor antagonist. Roxatidine is a potent and selective inhibitor of basal and stimulated gastric acid secretion through competitive blockade of H2-receptors. Total pepsin secretion is reduced in a dose-dependent manner. There is an independent mucosal protection action. Roxatidine is indicated for the treatment of peptic ulcer, gastro-oesophageal reflux disease, gastritis, upper gastrointestinal haemorrhage and Zollinger-Ellison syndrome also it can be used as a premedication before anaesthesia. Roxatidine possessed a robust estrogenic activity.