Effect of different doses of inhaled ciclesonide on lung function, clinical signs related to airflow limitation and serum cortisol levels in horses with experimentally induced mild to severe airway obstruction.
Authors: Lavoie J-P, Bullone M, Rodrigues N, Germim P, Albrecht B, von Salis-Soglio M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Ciclesonide for Equine Asthma Inhaled corticosteroids effectively manage equine asthma but often suppress serum cortisol with attendant systemic effects; this study evaluated ciclesonide, a newer corticosteroid theoretically offering improved safety margins. Researchers challenged 16 horses with mouldy hay to induce mild-to-severe airway obstruction, then administered ciclesonide at escalating doses (450–2700 µg twice daily or 3712.5 µg once daily) across three randomised, blinded cross-over studies, measuring pulmonary mechanics, clinical signs, and cortisol levels before treatment, at days 7 and 14, and post-treatment. The highest ciclesonide dose (1687.5 µg twice daily) significantly improved pulmonary resistance (2.7 to 1.6 cm H₂O/L/s), elastance (5.2 to 2.2 cm H₂O/L), and weighted clinical scores (13 to 10.8) by day 7—approaching the effects of systemic dexamethasone—whilst notably, serum cortisol remained unchanged across all ciclesonide doses, in stark contrast to dexamethasone-induced suppression (<50 nmol/L from day 3 onwards). For practitioners, ciclesonide offers a therapeutically robust inhaled option that effectively reduces airway obstruction and clinical signs without triggering the systemic cortisol suppression associated with other corticosteroid treatments, potentially minimising metabolic and immunological complications in horses requiring prolonged anti-inflammatory therapy.
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Practical Takeaways
- •Ciclesonide is an effective inhaled corticosteroid for treating equine asthma with similar lung function improvements to systemic dexamethasone but without cortisol suppression and associated systemic side effects
- •The improved safety profile of ciclesonide makes it suitable for longer-term management of asthma in horses where repeated systemic corticosteroid use is contraindicated
- •Experimentally induced asthma may respond differently to treatment than naturally occurring exacerbations, so clinical efficacy in field conditions requires further validation
Key Findings
- •Ciclesonide 1687.5 μg twice daily significantly improved pulmonary resistance (2.7±1.1 to 1.6±0.8 cm H2O/L/s), pulmonary elastance (5.2±3.1 to 2.2±1.3 cm H2O/L), and clinical scores (13±2.9 to 10.8±4.2) after 7 days of treatment
- •Dexamethasone produced similar improvements in lung function and clinical signs but caused systematic serum cortisol suppression (<50 nmol/L) from day 3 through day 3 post-treatment
- •Ciclesonide at all tested doses (450–2700 μg twice daily or 3712.5 μg once daily) did not suppress serum cortisol levels
- •Placebo had no significant beneficial effect on any measured parameter