famotidine brands

Molecular formula: C8H15N7O2S3

Histamine acts as a local hormone that stimulates the acid output by parietal cells via a paracrine mechanism. Neuroendocrine cells called enterochromaffin-like (ECL) cells lie close to the parietal cells and regulate the basal secretion of histamine. Histamine release is also promoted from stimulation by acetylcholine and gastrin, a peptide hormone. Gastrin (G) cells release gastrin, which works on CCK₂ receptors on ECL cells. This action promotes the release of histamine from ECL cells. Upon release, histamine acts on H₂ receptors expressed on the basolateral membrane of parietal cells, leading to increased intracellular cAMP levels and activated proton pumps on parietal cells. Proton pump releases more protons into the stomach, thereby increasing the secretion of acid. In conditions that are associated with acid hypersecretion such as ulcers, there is a loss of regulation of acid secretion. Famotidine works on H₂ receptors and blocks the actions of histamine. H2-receptor antagonists inhibit basal and nocturnal gastric acid secretion by competitive inhibition of the action of histamine at the histamine H2-receptors of the parietal cells. They also inhibit gastric acid secretion stimulated by food, betazole, pentagastrin, caffeine, insulin, and physiological vagal reflex. /Histamine H2-receptor antagonists/ Weak inhibitor of hepatic cytochrome p450 mixed function oxidase system. Famotidine is a competitive H2 receptor antagonist that inhibits basal, overnight, and pentagastrin-stimulated gastric acid secretion. Pharmacologically, it is three times more potent than ranitidine and 20 times more potent than cimetidine.

Source: PubChem (NCBI) · compound 5702160