METHYLPREDNISOLONE INCREASES SENSITIVITY TO BETA-ADRENERGIC AGONISTS WITHIN 48 HOURS IN BASENJI GREYHOUNDS

Background: Corticosteroids used in combination with bronchodilators are significantly more effective than placebo combined with bronchodilators in the acute treatment of bronchospasm. Because the time course for this effect is not known, and is of importance in the preoperative preparation of patients with reactive airway disease, the authors investigated the time course by which methylprednisolone increased sensitivity to the beta-adrenergic agonist, albuterol, in a dog model with airway hyperresponsiveness. Methods: Airway responsiveness to methacholine alone and in the presence of albuterol was determined before treatment with methylprednisolone in nine Basenji greyhounds. Each dog was then treated with methylprednisolone for 1 week. Airway responsiveness to methacholine in combination with albuterol was determined after 24 h, 48 h, and 1 week of methylprednisolone treatment. Results. Albuterol alone did not alter air-way responsiveness to methacholine in Basenji greyhounds before methylprednisolone treatment and after 24 h of methylprednisolone treatment. Methylprednisolone, however, significantly decreased pulmonary responses to methacholine in albuterol-pretreated dogs at 48 h. Conclusions. The authors concluded that methylprednisolone increased sensitivity to the beta-adrenergic agonist, albuterol, within 48 h.