Information about Ranitidine
Ranitidine is a histamine type 2 receptor antagonist (H2 blocker) which is widely used for treatment of acid-peptic disease and heartburn.
Liver safety of Ranitidine
Ranitidine has been linked to rare instances of clinically apparent acute liver injury.
Mechanism of action of Ranitidine
Ranitidine (ra ni' ti deen) was the second H2 blocker introduced into clinical practice in the United States and remains a commonly used agent for treatment of duodenal and gastric ulcer and gastroesophageal reflux disease. The H2 blockers are specific antagonists of the histamine type 2 receptor, which is found on the basolateral (antiluminal) membrane of gastric parietal cells. The binding of ranitidine to the H2 receptor results in inhibition of acid production and secretion, and improvement in symptoms and signs of acid-peptic disease. The H2 blockers inhibit an early, “upstream” step in gastric acid production and are less potent that the proton pump inhibitors, which inhibit the final common step in acid secretion. Nevertheless, the H2 blockers inhibit 24 hour gastric acid production by about 70% and are most effective in blocking basal and nocturnal acid production.
FDA approval information for Ranitidine
Ranitidine was first approved for use in the United States in 1983 and is now used widely both by prescription and over-the-counter. The listed indications for ranitidine are duodenal and gastric ulcer disease, gastroesophageal reflux and prevention of stress ulcers. Ranitidine is available by prescription in capsules of 150 and 300 mg in several generic forms, and in both oral and parenteral forms under the brand name Zantac. Over-the-counter formulations of ranitidine are usually tablets of 75 mg each.
Dosage and administration for Ranitidine
The typical recommended dose of ranitidine for therapy of peptic ulcer disease in adults is 150 mg twice daily or 300 mg once nightly for 4 to 8 weeks, and maintenance doses of 150 mg once daily. Lower, chronic or intermittent doses are used for therapy of heartburn and indigestion.
Side effects of Ranitidine
Side effects of ranitidine are uncommon, usually minor, and include diarrhea, constipation, fatigue, drowsiness, headache and muscle aches. Ranitidine is metabolized by, but minimally affects the activity of the hepatic cytochrome P450 enzymes, for which reason it is less likely to lead to drug-drug interactions than is cimetidine.
The antiulcer agents in clinical use