title: Comparison of 2 Doses for ACTH Stimulation Testing in Dogs Suspected of or Treated for Hyperadrenocorticism.
abstract: BACKGROUND
  Lowering the cosyntropin dose needed for ACTH stimulation would make the test more economical.
  
  
  OBJECTIVE
  To compare the cortisol response to 1 and 5 μg/kg cosyntropin IV in dogs being screened for hyperadrenocorticism (HAC) and in dogs receiving trilostane or mitotane for pituitary-dependent HAC.
  
  
  METHODS
  Healthy dogs (n = 10); client-owned dogs suspected of having HAC (n = 39) or being treated for pituitary-dependent HAC with mitotane (n = 12) or trilostane (n = 15).
  
  
  METHODS
  In this prospective study, healthy dogs had consecutive ACTH stimulation tests to ensure 2 tests could be performed in sequence. For the first test, cosyntropin (1 μg/kg IV) was administered; the second test was initiated 4 hours after the start of the first (5 μg/kg cosyntropin IV). Dogs suspected of having HAC or being treated with mitotane were tested as the healthy dogs. Dogs receiving trilostane treatment were tested on consecutive days at the same time post pill using the low dose on day 1.
  
  
  RESULTS
  In dogs being treated with mitotane or trilostane, the 2 doses were pharmacodynamically equivalent (90% confidence interval, 85.1-108.2%; P = 0.014). However, in dogs suspected of having HAC, the doses were not pharmacodynamically equivalent (90% confidence interval, 73.2-92.8%; P = 0.37); furthermore, in 23% of the dogs, clinical interpretation of test results was different between the doses.
  
  
  CONCLUSIONS
  For dogs suspected of having HAC, 5 μg/kg cosyntropin IV is still recommended for ACTH stimulation testing. For dogs receiving mitotane or trilostane treatment, a dose of 1 μg/kg cosyntropin IV can be used.
authors.affiliation: Department of Clinical Sciences, Auburn University, Auburn, AL.
authors.forename: C
authors.initials: C
authors.lastname: Aldridge
authors.affiliation: Department of Clinical Sciences, Auburn University, Auburn, AL. behreen@auburn.edu.
authors.forename: E N
authors.initials: EN
authors.lastname: Behrend
authors.affiliation: Department of Anatomy, Physiology, and Pharmacology, Auburn University, Auburn, AL.
authors.forename: R J
authors.initials: RJ
authors.lastname: Kemppainen
authors.affiliation: Department of Clinical Sciences, Auburn University, Auburn, AL.
authors.forename: T M
authors.initials: TM
authors.lastname: Lee-Fowler
authors.affiliation: Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA.
authors.forename: L G
authors.initials: LG
authors.lastname: Martin
authors.affiliation: Department of Small Animal Medicine and Surgery, University of Georgia, Athens, GA.
authors.forename: C R
authors.initials: CR
authors.lastname: Ward
authors.affiliation: VCA West Los Angeles Animal Hospital, Los Angeles, CA.
authors.forename: D
authors.initials: D
authors.lastname: Bruyette
authors.affiliation: Department of Mathematics and Statistics, Auburn University, Auburn, AL.
authors.forename: J
authors.initials: J
authors.lastname: Pannu
authors.affiliation: Department of Mathematics and Statistics, Auburn University, Auburn, AL.
authors.forename: P
authors.initials: P
authors.lastname: Gaillard
authors.affiliation: Department of Clinical Sciences, Auburn University, Auburn, AL.
authors.forename: H P
authors.initials: HP
authors.lastname: Lee
mesh_terms: D000308:Adrenocortical Hyperfunction / Q000175:diagnosis / Q000188:drug therapy / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D003366:Cosyntropin / Q000008:administration & dosage / Q000494:pharmacology*; D013196:Dihydrotestosterone / Q000031:analogs & derivatives / Q000627:therapeutic use; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D006728:Hormones / Q000008:administration & dosage; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008939:Mitotane / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D006728:Hormones; D013196:Dihydrotestosterone; D003366:Cosyntropin; D008939:Mitotane; D000324:Adrenocorticotropic Hormone; C009954:trilostane; D006854:Hydrocortisone
keywords: Adrenal; Cosyntropin; Mitotane; Trilostane