Nebulized dexamethasone in the treatment of horses with severe asthma

The hope is that the nebulized dex would lower the doses, and therefore side effects, than oral administered dex. It was not as effective as the oral administration and both treatments showed adrenal suppression. Parental dex is very effective at relieving the symptoms however does not cure the disease. You must address the triggering causes for good long term outcomes, see article for more.
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Nebulized dexamethasone sodium phosphate in the treatment of horses with severe asthma
J Vet Intern Med. 2021 Apr 4.
Authors
Selena de Wasseige 1 , Khristine Picotte 1 , Jean-Pierre Lavoie 1
Affiliation

1 Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada.

Abstract

Background: A study reported low systemic availability of injectable dexamethasone nebulized to healthy horses using the Flexineb mask. When used in horses with severe asthma and a different nebulizer, lack of efficacy and cortisol suppression were observed.

Hypothesis: Nebulized dexamethasone is as effective as PO administration for the treatment of severe asthma in horses.

Animals: Twelve horses with severe asthma from a research herd.

Methods: Randomized clinical trial. Horses were divided into 2 groups and received 5 mg of dexamethasone sodium phosphate by nebulization using a Flexineb mask (NE, n = 6) or PO (OR, n = 6) q24h for 7 days. Lung function and serum cortisol concentrations were evaluated at baseline, after 4 days of treatment (D4) and 1 day after the last treatment (D8). Data were analyzed using linear mixed models with Benjamini-Hochberg adjustments.

Results: Lung resistance significantly improved at D4 (mean decrease ± SD, -1.5 ± 0.45 cm H₂O/L/s; 95% confidence interval [CI], -2; -0.6) and D8 (-1.4 ± 0.45 cm H₂O/L/s; 95% CI, -2.4; -0.5) compared to baseline in the OR group only (P = .004 and .01, respectively). Serum cortisol concentration was significantly decreased at D4 and D8 for both groups (maximum decrease, -1.2 ± 0.3 μg/dL; 95% CI, -1.9; -0.6 at D4 for NE group and -2.2 ± 0.3 μg/dL; 95% CI, -2.8; -1.6 at D8 for OR group; P < .001). Conclusions and clinical importance: Oral, but not nebulized dexamethasone is an effective therapy for horses with severe asthma and both treatment modalities inhibit the hypothalamic-pituitary-adrenal axis. Keywords: corticosteroids; cortisol; heaves; hypothalamic-pituitary-adrenal axis suppression; inhalation; lung; recurrent airway obstruction.