H2 receptor antagonist.

Indications: benign gastric and duodenal ulceration, stomal ulcer, reflux oesophagitis, Zollinger-Ellison syndrome, other conditions where reduction of gastric acidity is beneficial.

Cautions: Should be used with caution in impaired renal function, hepatic impairment; dosage modification required, avoid use in patients with history of acute porphyria, in pregnancy and breast feeding, they may mask symptoms of gastric cancer, long term therapy may cause vitamin B 12 deficiency.

Contra-indications: Hypersensitivity to ranitidine.

Side effect: Diarrhea and other gastro-intestinal disturbances, dizziness, rash, tiredness; occasionally, gynaecomastia and impotence (in high doses), reversible confusional states, reversible liver damage, headache; rarely, decreased blood counts, alopecia, muscle or joint pain, bradycardia, acute pancreatitis, rarely visual disturbances, tachycardia, agitation, erythema multiforme, alopecia, vasculitis, and very rarely interstitial nephritis.

Dose: by mouth, adult and child over 12 years, 150 mg twice daily or 300 mg at night for 4 to 8 weeks in benign gastric and duodenal ulceration, up to 6 weeks in chronic episodic dyspepsia, and up to 8 weeks in NSAID – associated ulceration (in duodenal ulcer 300 mg can be given twice daily for 4 weeks to achieve higher healing rate). Child over 3 years, (benign gastric and duodenal ulceration) 2-4 mg / kg (max 150 mg) twice daily for 4 to 8 weeks.

Duodenal ulcer associated with H. pylori, 300 mg twice daily, require combination therapy. See under guidelines for treatment of H. pylori.

Prophylaxis of NSAID – associated gastric or duodenal ulcer, adult and child over 12 years 300 mg twice daily. Gastro- oesophageal reflux disease, adult and child over 12 years, 150 mg twice daily or 300 mg at night for up to 8 weeks or if necessary 12 weeks (moderate to severe, 600 mg daily in 2-4 divided doses for up to12 weeks), long term treatment of healed gastro-oesophageal reflux disease, 150 mg twice daily; child over 3 years, 2.5 – 5 mg / kg (max. 300 mg) twice daily.

Zollinger- Ellison syndrome (proton pump inhibitor is preferred), adult and child over 12 years, 150 mg 3 times daily, doses up to 6 g daily in divided doses have been used.

Gastric acid reduction (prophylaxis of acid aspiration) in obstetrics. By mouth 150 mg at onset of labour, then every 6 hours, surgical procedures, by intramuscular or slow intravenous injection, 50 mg 45-60 minutes before induction of anaesthesia (intravenous injection diluted to 20 ml and given over at least 2 minutes), or by mouth, 150 mg 2 hours before induction of anaesthesia and also when possible on the preceding evening.

By intramuscular injection, 50 mg every 6-8 hours.

By slow intravenous injection, 50 mg diluted to 20 ml and given over at least 2 minutes, may be repeated every 6-8 hours.

By intravenous infusion, 25mg / hour for 2 hours, may be repeated every 6-8 hours.

Prophylaxis of stress ulceration, initial slow intravenous injection of 50 mg (as above) then continuous infusion, 125-250 mcg / kg / hour (may be followed by 150 mg twice daily by mouth when oral feeding commences)