New Approach to Equine Asthma: Nebulization and Fatty Acids

Corticosteroid anti-inflammatory drugs such as prednisone or prednisolone help horses suffering from equine asthma, including heaves. Although they are effective, the long-term use of such medications has important and potentially life-threatening sequelae such as laminitis, altered bone metabolism, decreased response to vaccination, development of systemic infections, and alterations in the hypothalamic-pituitary-adrenal axis.

“Inhaled corticosteroids such as fluticasone and beclomethasone have fewer side effects than orally administered corticosteroids; however, these medications are frequently cost prohibitive for many owners,” relayed Kathleen Crandell, Ph.D., an equine nutritionist for Kentucky Equine Research (KER) located in Versailles, Kentucky.

One group of researchers* suggested that nebulization of standard injectable formulations of dexamethasone sodium phosphate (DSP) could serve as an economical, safe, and effective alternative to commercial inhaled corticosteroids for managing equine asthma.

Specifically, the research team administered DSP either via nebulization or intravenous injection to five horses. They found that nebulized DSP was only minimally absorbed systemically (i.e., it remained in the lung tissue to decrease inflammation) and had no impact on the hypothalamic-pituitary-adrenal axis—a major player in “stress” responses involving many of the body’s key hormones.

Further study is needed before the research team would recommend this treatment in the field.

“In lieu of nebulized DSP, owners of horses diagnosed with equine asthma remain reliant upon standard management strategies to minimize exposure to inhaled particles that can exacerbate their condition, as well as inhaled corticosteroids.

The recently revised Consensus Statement on equine asthma** also recommends using omega-3 fatty acids to help manage equine asthma.

“KER’s fish oil supplement EO•3 contains the omega-3 fatty acids DHA and EPA. This product is top-dressed onto the feed and helps horses with equine asthma, including inflammatory airway disease in young, athletic horses,” Crandell said.

*Haspel, A.D., S. Giguère, K.A. Hart, et al. Bioavailability and tolerability of nebulised dexamethasone sodium phosphate in adult horses. Equine Veterinary Journal. In press.

**Couëtil, L.L., J.M. Cardwell, V. Gerber, et al. 2016. Inflammatory airway disease of horses—Revised  consensus statement. Journal of Veterinary Internal Medicine. 30(2):503-515.