Ranitidine, a histamine H2-receptor antagonist, has been reported to be 4- to 10-fold more potent compared to cimetidine with regard to the inhibition of stimulated gastric acid secretion.

According to therapeutic trials, ranitidine is an effective agent and a potential alternative to cimetidine with regard to improvement in the rate of healing of duodenal and gastric ulcers over 4 to 6 weeks. Additionally, a single 150mg night-time dose of ranitidine has been shown to reduce the incidence of ulcer recurrence.

Ranitidine also controls gastric hyperacidity and heals which do not respond to cimetdine treatment for months. Studies have shown that ranitidine inhibits basal gastric acid secretion and the secretion stimulated by pentagastrin, histamine and meals.

In healthy individuals and in duodenal ulcer patients, ranitidine has been shown not to significantly affect serum gastrin, pancreatic or mucus secretion. Of note, ranitidine does not have antiandrogen effects, unlike cimetidine.

Open trials, placebo-controlled trials and comparative trials with cimetidine, have reported the healing rate of duodenal ulcers after 4 weeks of ranitidine treatment to vary from 60% to 100%. Ranitidine 150mg twice a day has been shown to be more effective than placebo and not significantly different from cimetidine 1000mg a day, given in 4 divided doses.

Ranitidine 300mg a day has also been reported to be effective in the treatment of peptic ulcers not responding to cimetidine 1 to 1.6g daily for 2 to 36 months. Ranitidine is also effective in patients with reflux esophagitis. Studies in Zollinger-Ellison syndrome have also found ranitidine at doses of up to 900mg a day to control symptoms and heal ulcers.

Ranitidine is generally well tolerated, with side effects such as skin rash, headache and dizziness, reported in a few patients.

Source: Brogden RN, Carmine AA, Heel RC, et al. Ranitidine: A Review of its Pharmacology and Therapeutic Use in Peptic Ulcer Disease and Other Allied Diseases. Drugs 1982;24:267-303.