Safety of cimetidine.

Our review of published material, manufacturer's files, and submissions to the United States Food and Drug Administration indicates that cimetidine is safe for short term use (up to 8 weeks). This judgment is based on a total experience with over 3000 patients. Clinically insignificant elevations of serum creatinine occur in a high percentage of patients, persisting until the end of therapy, then disappearing. Gynecomastia occurred in some patients on long term therapy.