Cimetidine is used for the treatment of Zollinger-Ellison syndrome (ZES). However, the reduction in acid secretion may sometimes be insufficient and the side effects over the long run may lead to treatment discontinuation.

Mignon et al reported the beneficial effects of ranitidine in a patient with ZES who had to discontinue cimetidine treatment due to development of gynecomastia.

A 42-year old male with pancreatic gastrinoma was treated with caudal pancreatectomy, 4 months after supra-selective vagotomy done for complicated duodenal ulcer. A month after pancreatectomy (in February), cimetidine 2 g daily was prescribed for persisting duodenal ulcer and raised basal acid output (BAO) (21 mEq/h). The patient developed bilateral gynecomastia in May, which persisted through treatment with cimetidine, and the patient reported impotence. In July, healing of the duodenal ulcer was noted; however, there was considerable duodenitis. The gynecomastia became painful and the patient stopped taking cimetidine in October.

After 9 days, a kissing ulcer of the duodenal cap was noted on upper GI endoscopy. BAO was 14.9 mEq/h. Serum gastrin was 600 to 900 pg/ml.

A study of 24 h gastric acidity and measurement of gastric pH was done comparing the efficacy of ranitidine 600 mg/day and cimetidine 2,400 mg/day, on two different occasions. Ranitidine was associated with a prolonged reduction in gastric H⁺ activity.

The patient was prescribed ranitidine 600 mg/day. After a span of 6 weeks, both duodenal ulcers had healed, sexual activity returned normal and gynecomastia had been relieved.

Ranitidine thus appeared to be a potential alternative to cimetidine for the treatment of ZES. The drug has no effect on the breast or male sexual function.

Source: Mignon M, Vallot TH, Mayeur S, Bonfils S. Ranitidine and cimetidine in Zollinger-Ellison syndrome. Br J Clin Pharmac. 1980;10:173-174.