Endocrine and immunologic effects of inhaled fluticasone propionate in healthy dogs.
BACKGROUND
Inhaled glucocorticoids reduce airway inflammation while minimizing systemic effects in several species.


OBJECTIVE
Inhaled fluticasone suppresses the hypothalamic-pituitary-adrenal axis (HPAA), modifies immune function, and induces clinical signs to a lesser extent than PO-administered prednisone in dogs.


METHODS
Seven healthy adult pet dogs.


METHODS
Dogs were randomized to 1 of 3 treatment groups in a crossover design: fluticasone propionate (220 mug actuation of a metered dose inhaler delivered via a spacer and mask, q12h), placebo (spacer and mask alone, q12h), or prednisone (1 mg/kg PO q24h). Each treatment was administered for 3 weeks followed by a 4-week washout. Appetite, attitude, and water consumption were recorded during the last week of each treatment period. Urine cortisol : creatinine ratios, ACTH stimulation tests, white blood cell counts, lymphocyte phenotype, and serum IgM and IgA concentrations were recorded at each baseline and after the last day of each treatment. Clinical observations were expressed descriptively. Friedman's test was applied to all data comparisons. Pairwise comparisons were made with a mixed model analysis when data were normally distributed, whereas signed rank tests were used otherwise (significance P-value <.01).


RESULTS
Appetite and water consumption increased during prednisone treatment. Peak serum cortisol concentrations post-ACTH were significantly decreased in prednisone- and fluticasone-treated dogs compared with placebo (prednisone > fluticasone). Serum IgM concentrations were significantly decreased in dogs treated with prednisone.


CONCLUSIONS
As used, fluticasone suppresses the HPAA to a lesser extent than prednisone and may avert systemic signs associated with PO-administered glucocorticoids in dogs.
Cohn
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Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA. cohnl@missouri.edu
DeClue
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Reinero
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D000280:Administration, Inhalation; D000730:Androstadienes / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000494:pharmacology; D001772:Blood Cell Count / Q000662:veterinary; D018592:Cross-Over Studies; D004285:Dogs; D004327:Drinking Behavior / Q000187:drug effects; D004703:Endocrine System / Q000187:drug effects*; D005260:Female; D000068298:Fluticasone; D006854:Hydrocortisone / Q000097:blood; D007107:Immune System / Q000187:drug effects*; D007070:Immunoglobulin A / Q000097:blood; D008297:Male; D011241:Prednisone / Q000008:administration & dosage / Q000494:pharmacology
D000730:Androstadienes; D000893:Anti-Inflammatory Agents; D007070:Immunoglobulin A; D000068298:Fluticasone; D011241:Prednisone; D006854:Hydrocortisone