We have treated four cetaceans (two bottlenose dolphins, one false killer whale, and one beluga whale) with oral megestrol acetate after they had failed to maintain or gain weight during or following the course of an illness. After receiving a starting dose of 0.4-0.6 mg/kg daily, appetite appeared to improve within two to three days. Over the next several months the megestrol acetate dose was maintained at the lowest therapeutically effective level. Treatment duration averaged three to five months. We observed weight gain in all cases, ranging from 18% to 27%.

None of these animals experienced adverse side effects associated with the use of megestrol acetate. When indicated, megestrol acetate has proven to be an effective pharmacologic tool for the treatment of weight loss in cetaceans. It helps in maintaining an oral route for the administration of medication in certain patients and stimulates appetite in those who have failed to gain sufficient weight following treatment of an illness. It is hoped that by pharmacologically assisting appetite with a relatively safe drug, such as megestrol acetate, we can eliminate the need to force feed or use potentially undesirable drugs, such as corticosteroids or diazepam, in our anoretic patients.