Results of clinical examinations, laboratory tests, and ultrasonography in dogs with pituitary-dependent hyperadrenocorticism treated with trilostane.
OBJECTIVE
To determine the efficacy of trilostane, a 3beta-hydroxysteroid dehydrogenase inhibitor, in dogs with pituitary-dependent hyperadrenocorticism (PDH).


METHODS
11 dogs with PDH.


METHODS
The initial dose of trilostane was 30 mg, PO, q 24 h for dogs that weighed < 5 kg and 60 mg, PO, q 24 h for dogs that weighed > or = 5 kg. A CBC count, serum biochemical analyses, urinalysis, ACTH stimulation test, and ultrasonographic evaluation of the adrenal glands were performed in each dog 1, 3 to 4, 6 to 7, 12 to 16, and 24 to 28 weeks after initiation of treatment.


RESULTS
All dogs responded well to treatment. All had reductions in polyuria-polydipsia and panting and an increase in activity. Polyphagia decreased in 9 of 10 dogs, and 9 of 11 dogs had improvement of coat quality and skin condition. Concentration of cortisol after ACTH stimulation significantly decreased by 1 week after initiation of treatment. After treatment for 6 months, clinical signs resolved in 9 dogs. In the other 2 dogs, marked clinical improvement was reported for 1 dog, and moderate improvement was reported in the other dog. Ultrasonographically, there was a considerable change in the parenchyma and an increase in size of the adrenal glands. Adverse effects consisted of 1 dog with transient lethargy and 1 dog with anorexia.


CONCLUSIONS
Trilostane is an efficacious and safe medication for treatment of dogs with PDH. Additional studies in a larger group of dogs and characterization of progressive changes in adrenal glands are needed.
Ruckstuhl
Nadja S
NS
Clinic for Small Animal Internal Medicine, University of Zurich, Switzerland.
Nett
Claudia S
CS
Reusch
Claudia E
CE
D000308:Adrenocortical Hyperfunction / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage; D000818:Animals; D001772:Blood Cell Count / Q000662:veterinary; D001774:Blood Chemical Analysis / Q000662:veterinary; D013196:Dihydrotestosterone / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use*; D004283:Dog Diseases / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy*; D004285:Dogs; D004791:Enzyme Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D010900:Pituitary Diseases / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000662:veterinary*; D011141:Polyuria / Q000188:drug therapy / Q000662:veterinary; D011446:Prospective Studies; D014463:Ultrasonography
D004791:Enzyme Inhibitors; D013196:Dihydrotestosterone; D000324:Adrenocorticotropic Hormone; C009954:trilostane; D006854:Hydrocortisone