The World Health Organization's ATC classification organizes medical drugs based on therapeutic properties, chemical composition, and anatomy. It helps make essential medicines readily available globally and is widely used in the pharmaceutical industry.
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.