Common Medications Used for Treatment of Equine Asthma

Beta-2 agonists

Clenbuterol: 0.8–3.2 mcg/kg, PO, q 12 h. FDA approved for equine chronic obstructive pulmonary disease. Tachyphylaxis is possible.

Albuterol: 1–2 mcg/kg, inhaled via an equine-specific mask, q 1–3 h. Short duration of action.

Muscarinic antagonists

Atropine: 0.02 mg/kg, IV. Short acting, potent bronchodilator. Tachycardia and gastrointestinal adverse effects are possible. Use only as an emergency rescue treatment.

Butylscopolammonium bromide (hyoscine butylbromide): 0.3 mg/kg, IV. Very short (< 30 min) duration. Fewer adverse effects than atropine. FDA-approved for equine use as an intestinal antispasmodic.

Ipratropium bromide: 0.18 – 0.3 mg per horse, inhaled via an equine-specific mask, q 4-8 h. Low systemic absorption allows for fewer adverse effects.

Corticosteroids

Systemic

Dexamethasone: 0.04 mg/kg, IV or IM, every 24 h; 0.05 mg/kg, PO, q 24 h). For long-term treatment.

Prednisolone: 1.1–2.2 mg/kg, PO, q 24 h. Taper to lowest effective dose. For long-term treatment.

Inhaled

Fluticasone: (1–6 mcg/kg, inhaled via an equine-specific mask, q 12 h). Systemic absorption is possible.

Beclomethasone: 1–8 mcg/kg, inhaled via an equine-specific mask, q 12 h. Systemic absorption is possible.

Ciclesonide: 2744 mcg (8 actuations) per horse, inhaled via an equine-specific mask, q 12 h for 5 days, followed by 4116 mcg per horse (12 actuations), inhaled via an equine-specific mask, q 12 h for 5 more days. FDA-approved for severe equine asthma.