Ranitidin

Ranitidin, spelled ranitidine, is a histamine-2 receptor antagonist used to decrease stomach acid production. It competitively blocks H2 receptors on gastric parietal cells, reducing acid secretion and increasing gastric pH. It is used to treat active ulcers due to acid peptic disease, gastroesophageal reflux disease (GERD), and dyspepsia; it is also used to prevent ulcers in NSAID users and, in some settings, to treat Zollinger-Ellison syndrome. It is commonly employed for short-term relief of heartburn and related acid symptoms.

Ranitidine was launched in 1983 by Glaxo (later GlaxoSmithKline) and became widely used under the brand name Zantac. It is available in oral tablets, liquid suspensions, and injectable forms, and is sold over the counter in many countries for short-term relief of heartburn and acid symptoms.

Regulatory status: In 2020, authorities worldwide identified nitrosamine impurities, particularly N-nitrosodimethylamine (NDMA), in ranitidine products. NDMA is classified as a probable human carcinogen. Following these findings, many manufacturers recalled ranitidine products and regulators advised against using ranitidine, with several agencies removing it from the market or restricting its use. Ongoing monitoring and testing have limited or halted sales in many jurisdictions, with some places permitting resumed use only after strict NDMA testing; others require a switch to alternative acid-suppressing medicines such as other H2 blockers or proton pump inhibitors.

Adverse effects are usually mild and may include headache, dizziness, constipation, or diarrhea. Less common effects include confusion (especially in the elderly), liver or kidney problems, and interactions with drugs whose absorption depends on gastric pH. Ranitidine should be used with caution in pregnancy and kidney disease, and patients should avoid long-term self-treatment without medical supervision.