Pulmonary response of severely asthmatic horses after intra‐articular administration of methylprednisolone

Abstract

Background: Intra-articular (IA) administration of corticosteroids is performed routinely in equine practice. The lung function of severe asthmatic horses has recently been shown to be improved by IA triamcinolone acetonide (TA). We therefore hypothesised that IA methylprednisolone acetate (MPA), another commonly used corticosteroids, would also decrease the airway obstruction in severe asthmatic horses. Objectives: To compare the effects of intra-articular (IA) and intramuscular (IM) methylprednisolone acetate (MPA) administration on lung function and serum cortisol levels in horses with severe asthma. Study design: Randomised and controlled experiments on severe asthmatic research animals. Methods: Severe asthmatic horses in exacerbation were administered 200 mg of MPA either intramuscularly (n = 6) or via intra-articular injections in the tarsocrural joints (n = 6; 100 mg/joint). Serum cortisol concentration and pulmonary function was measured for 8 days. Results: A significant decrease in pulmonary resistance in the IA group (P = .003, mean diff 1.14) on day 1 in comparison with baseline was observed. A significant decrease from baseline was also observed on serum cortisol values in the IA group 6 hours after injection (P = .001, mean diff 44.5), and at day 1 (P = .003, mean diff 45.1). Main limitations: Joint health was not evaluated in the current study and the physiological response of the severe asthmatic horses might deviate from that of the milder forms of asthma. Conclusions: MPA IA administration improves the lung function of severe asthmatic horses. However, this effect was mild and of a short duration.

Glucocorticoid treatment in horses with asthma: A narrative review

“…40 Methylprednisolone administered intra-articularly (200 mg once) briefly suppresses cortisol production, from 6 to 24 hours after the injection. 55 Although a month-long administration of inhaled fluticasone at a decreasing dosage does not modify the adrenocortical function, 26 longer administration (11 months) suppresses the endogenous cortisol production in SEA horses. 124 Inhaled beclomethasone (1320 μg q12h, 7 days) suppresses cortisol, which normalizes 2 days after discontinuation of treatment.…”

“…Indeed, the pulmonary resistance decreased within 24 hours, but returned to baseline 3 days after administration. 55 The same dose administered intramuscularly does not relieve airway obstruction. 55 Isoflupredone acetate (0.03 mg/kg IM q24h, 2 weeks) improves the lung function similarly to dexamethasone (0.04 mg/kg IV q24h, 2 weeks) in SEA.…”

“…55 The same dose administered intramuscularly does not relieve airway obstruction. 55 Isoflupredone acetate (0.03 mg/kg IM q24h, 2 weeks) improves the lung function similarly to dexamethasone (0.04 mg/kg IV q24h, 2 weeks) in SEA. 40 However, the hypokalemia resulting from the high mineralocorticoid activity of isoflupredone is a concern in horses.…”

“…Indeed, the pulmonary resistance decreased within 24 hours, but returned to baseline 3 days after administration. 55 The same dose administered intramuscularly does not relieve airway obstruction. 55 …”

“… 40 Methylprednisolone administered intra‐articularly (200 mg once) briefly suppresses cortisol production, from 6 to 24 hours after the injection. 55 …”