Ranitidine occurs as histamine H₂-receptor antagonist that inhibits stomach acid production, and commonly used in the treatment of peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD). These are presently marketed by GlaxoSmithKline under the brand name Zantac.

Clinical use
Independent article: H2-receptor antagonist

Certain preparations of zantac come available over the counter (OTC) in various countries. In the United States, 75 mg & 150 mg tablets come available OTC. Inside Australia, microscopic packs of 150 mg & 300 mg tablets come Schedule 2 Pharmacy Medicines. Big drugs & package sizes however involve the guide.

Outside of the United States, zantac is combined sustaining bismuth (which acts as a mild antibiotic) as a citrate salt (ranitidine atomic number 83 citrate, Tritec®), to handle Helicobacter pylori contagions. This combination is commonly given using clarithromycin, another antibiotic drug.

History and development
Ranitidine was developed by Glaxo (nowadays GlaxoSmithKline) in an effort to match a profits of Smith, Kline & French (also now GlaxoSmithKline) with the first histamine H₂-receptor antagonist cimetidine. Ranitidine was a as well a symptom of a rational drug-project run utilising the, by so, fairly refined model of the histamine H_Two-receptor & quantitative structure-activity relationships (QSAR).

Glaxo refined a model farther by replacing a imidazole-ring of cimetidine by owning the furan-ring with the nitrogen-containing substituent, and inside doing thus developed zantac. Ranitidine was uncovered to have a far-improved tolerability profile (we.e. fewer adverse drug reactions), longer-lasting action, & tenner days a activity of tagamet.

Ranitidine was introduced within 1981 and was the world's biggest-selling prescription drug by 1988. It has since largely been superseded per possibly thomas more effectual proton pump inhibitors, with omeprazole becoming the biggest-selling drug for numerous years.