Ranitidine

Ranitidine
N,N-dimethyl-5-[2-(1-methylamino- 2-nitrovinylamino)ethylthiomethyl]furfurylamine
CAS number 66357-35-5	ATC code
Chemical formula	C13H22N4O3S
Molecular weight	314.4
Bioavailability	~50%
Metabolism	hepatic
Elimination half-life	2 hours
Excretion	renal
Pregnancy category	B1 (Australia)
Legal status	Schedule 4 (Australia) POM (UK)
Routes of administration	oral, intravenous

Ranitidine is a 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). It is currently marketed by GlaxoSmithKline under the trade name Zantac.

Clinical use

Main article: H2-receptor antagonist

History and development

Ranitidine was developed by Glaxo (now GlaxoSmithKline) in an effort to match the success of Smith, Kline & French (also now GlaxoSmithKline) with the first histamine H₂-receptor antagonist cimetidine. Ranitidine was the also the result of a rational drug-design process utilising the, by then, fairly refined model of the histamine H₂-receptor and quantitiative structure-activity relationships (QSAR).

Glaxo refined the model further by replacing the imidazole-ring of cimetidine with a furan-ring with a nitrogen-containing substituent, and in doing so developed ranitidine. Ranitidine was found to have a far-improved tolerability profile (i.e. fewer adverse drug reactions), longer-lasting action, and ten times the activity of cimetidine.

Ranitidine was introduced in 1981 and was the world's biggest-selling prescription drug by 1988. It has since largely been superceded by the even more effective proton pump inhibitors, with omeprazole becoming the biggest-selling drug for many years.