Ketoconazole (Generic) Tablets, 200-mg

Gastrointestinal signs of anorexia, vomiting, and/or diarrhea and weight loss are the most common adverse effects seen with ketoconazole therapy and are more prevalent in cats. Dividing the dose and/or giving it with meals may minimize gastrointestinal side effects. Appetite stimulants such as oxazepam or cyproheptadine may also be of benefit in cats.

Hepatic toxicity consisting of cholangiohepatitis and increased liver enzymes has been reported with ketoconazole, and may be either idiosyncratic in nature or a dose-related phenomenon. Cats may be more prone to developing hepatotoxicity than dogs. While liver enzymes should be monitored during therapy, an increase does not necessarily mandate dosage reduction or discontinuation unless concomitant anorexia, vomiting, diarrhea, or abdominal pain is present. Thrombocytopenia has also been reported with ketoconazole therapy, but is rarely encountered. A reversible lightening of haircoat may also occur in pets treated with ketoconazole. Cataracts in dogs, anecdotally attributed to ketoconazole therapy has been reported.

Ketoconazole has a transient dose-related suppressant effect on gonadal and adrenal steroid synthesis. Doses as low as 10 mg/kg depressed serum testosterone levels in dogs within 3-4 hours after dosing, but levels returned to normal within 10 hours. Doses of 30 mg/kg/day have been demonstrated to suppress serum cortisol levels in dogs with hyperadrenocorticism. Dogs undergoing high dose antifungal therapy may need additional glucocorticoid support during periods of acute stress.