Roxatidine

For the treatment of disorders of the upper gastro intestinal region that are due to an excess of hydrochloric acid in the gastric juice, i.e. duodenal ulcers, benign gastric ulcers. Also for prophylaxis of recurrent gastric and duodenal ulcers.

Roxatidine acetate suppresses the effect of histamine on the parietal cells of the stomach (H2-receptor antagonist). This suppressive action is dose-dependent. As a result, the production and secretion, particularly of gastric acid, are reduced. Roxatidine acetate has no antiandrogenic effects and does not influence drug-metabolizing enzymes in the liver.

The H2 antagonists are competitive inhibitors of histamine at the parietal cell H2 receptor. They suppress the normal secretion of acid by parietal cells and the meal-stimulated secretion of acid. They accomplish this by two mechanisms: histamine released by ECL cells in the stomach is blocked from binding on parietal cell H2 receptors which stimulate acid secretion, and other substances that promote acid secretion (such as gastrin and acetylcholine) have a reduced effect on parietal cells when the H2 receptors are blocked.

Zollinger-Ellison syndrome: 75 mg bid.

Gastro-oesophageal reflux disease: 75 mg bid or 150 mg at bedtime for 6-8 wk.

Premedication before anaesthesia: 75 mg in the evening on the day before surgery and repeated 2 hr before induction of anaesthesia. Alternatively, 150 mg once on the night before surgery.

Peptic ulcer: 150 mg at bedtime or 75 mg bid daily for 4-6 wk. Maintenance: 75 mg at bedtime.

Gastritis: 75 mg once daily in the evening..

May affect serum levels of protease inhibitors.

Lactation, Porphyria.

Occasional headache, GI disturbances, gynaecomastia, alopecia, blood dyscrasias, pancreatitis, sleep disturbances, restlessness, rarely dizziness. Hypersensitivity reactions e.g. rash and itching reported occasionally. Changes in pulse rate and transient impairment of sexual drive. Possible increase in liver enzyme activity. May reduce leucocytes and/or thrombocytes.

Pregnancy category is not classified. Contraindications in lactation.

Renal and hepatic impairment, pregnancy. May mask the symptoms of gastric malignancy.

H2 receptor antagonist.

Renal Impairment:

Zollinger-Ellison syndrome:

• CrCl <20: 75 mg every 2 days.
• CrCl 20-50: 75 mg at bedtime.

Gastro-oesophageal reflux disease:

• CrCl <20: 75 mg every 2 days.
• CrCl 20-50: 75 mg at bedtime.

Peptic ulcer:

• CrCl <20: 75 mg every 2 days.
• CrCl 20-50: 75 mg at bedtime.

Gastritis:

• CrCl <20: 75 mg every 2 days.
• CrCl 20-50: 75 mg at bedtime.