Safety evaluation of cimetidine: report at the termination of a seven-year study in dogs.

Abstract

Cimetidine in tablet form was administered orally daily to eight male and four female beagle dogs at a dose level of 144 mg kg-1 for 385 weeks. Four male and two female control dogs received placebo tablets. Treatment with cimetidine did not affect the clinical condition of the dogs, but was associated with a slightly less rapid weight gain. Five dogs (two cimetidine-treated and three controls) were killed during the course of the study for reasons not related to treatment. Treatment with cimetidine did not affect haematological, clinical chemical, urinalysis or electrocardiographic parameters. Multiple biopsies of gastric mucosa taken at intervals of approximately six months from Week 177 to Week 363 showed no change which could be attributed to treatment with cimetidine. There were no toxic effects on the gastric mucosa of any dog. At necropsy no treatment-related findings were reported except for reduction in prostate size in 6/8 males receiving cimetidine. This was expected in view of previous experience with cimetidine.