Toxicity of high doses of griseofulvin in cats

Eight adult cats were treated with griseofulvin (110 to 145 mg/kg of body weight) daily for 11 weeks; 2 control cats were given a gelatin capsule daily. Hemograms and hepatic enzyme activities were monitored weekly for all cats. Bone marrow examinations were performed before administration of the drug and twice during the study. Cats were observed for untoward clinical effects. Signs of toxicosis (clinical, hematologic, or hepatic) were not found at any time during, or at the cessation of, the study. Although the sample number of treated cats was small, it was concluded that hematologic or hepatic abnormalities that develop with the use of high-dose griseofulvin treatment may be an idiosyncratic reaction found only in a few cats.