Liver tests in dogs receiving anticonvulsant drugs (diphenylhydantoin and primidone).

Two groups of adult female dogs were given diphenylhydantoin or primidone orally for 82 days. Plasma glutamic-pyruvic transaminase (GPT), alkaline phosphatase (AP) and gamma-glutamyl transferase (GGT) activity, total plasma bilirubin (TBR) concentration, fasting bile acid level and percent sulfobromophthalein (% BSP) retention were determined in the dogs prior to and after treatment. Plasma GPT and AP showed persistent increases in some dogs, while occasional increases occurred in the remaining dogs in both groups. The plasma enzymes returned to normal 5 wk after treatment. Plasma GGT, TBR, fasting bile acids and % BSP retention were normal during the study