title: Mitotane treatment of 32 dogs with cortisol-secreting adrenocortical neoplasms.
abstract: Thirty-two dogs with hyperadrenocorticism caused by cortisol-secreting adrenocortical neoplasia were treated with mitotane at an initial daily induction dosage of 27.5 to 75.0 mg/kg of body weight (mean, 46.3 mg/kg) for 10 to 14 days. All dogs received daily maintenance glucocorticoid supplementation during the induction period. After 2 weeks, the ACTH-stimulated serum cortisol concentration had decreased to within or below the reference range for baseline cortisol concentration in 18 (56.3%) of the 32 dogs; the remaining 14 (43.7%) still responded to ACTH administration with serum cortisol concentrations above the reference range. In these 14 dogs, mitotane was continued at a higher daily dosage (mean, 60.7 mg/kg) for an additional 1 to 9 weeks. Serum cortisol concentration subsequently fell within or below the reference range for baseline cortisol concentration in all but 1 dog. In 30 of the 32 dogs, mitotane was continued at an initial mean maintenance dosage of 101.6 mg/kg/wk, divided into 2 to 5 doses. Twenty-two dogs received prednisone daily (0.2 mg/kg) throughout the maintenance period. One or more relapses occurred in 19 (63%) of the 30 dogs. In dogs with relapse, the mean maintenance mitotane dosage was increased from 98.1 mg/kg/wk to a high of 212.4 mg/kg/wk. After a mean maintenance treatment time of 13.2 months, final mean maintenance dosage required in the 30 dogs ranged from 35.3 to 1,273 mg/kg/wk. Adverse effects were seen in 19 (59.4%) of the 32 dogs as a result of a drug toxicosis associated with high-dosage administration of mitotane, low serum cortisol concentration, or both.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Environmental Studies, School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.
authors.forename: P P
authors.initials: PP
authors.lastname: Kintzer
authors.forename: M E
authors.initials: ME
authors.lastname: Peterson
mesh_terms: D000224:Addison Disease / Q000139:chemically induced / Q000188:drug therapy / Q000662:veterinary; D000306:Adrenal Cortex Neoplasms / Q000150:complications / Q000188:drug therapy / Q000378:metabolism / Q000662:veterinary*; D000308:Adrenocortical Hyperfunction / Q000209:etiology / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone; D000818:Animals; D004283:Dog Diseases / Q000188:drug therapy* / Q000209:etiology; D004285:Dogs; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism*; D008297:Male; D008939:Mitotane / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D012074:Remission Induction; D016896:Treatment Outcome
chemical_list: D005938:Glucocorticoids; D008939:Mitotane; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone