Drug effects on exercise-induced late asthmatic responses.

Disodium cromoglycate, prednisolone, beclomethasone and salbutamol were administered prior to the cycle ergometer exercise task separately to different groups of children with exercise-induced dual asthmatic reaction. Pre-treatment with disodium cromoglycate of ten asthmatics totally inhibited the dual reaction. Prednisolone treatment of eleven asthmatics and beclomethasone treatment of five asthmatics did not inhibit the early response but only the late response. Salbutamol treatment of ten asthmatics mainly inhibited the early phase reaction. Changes in neutrophil chemotactic activity correlated with airflow limitation in the disodium cromoglycate and prednisolone study, however, there were some discrepancies between the changes in FEV1 and neutrophil chemotactic activity in the beclomethasone and salbutamol studies. These findings suggest that exercise-induced dual asthmatic reaction are modified by disodium cromoglycate, prednisolone, beclomethasone or salbutamol in a mechanism which may be different in each drug and that there are similarities in the inflammatory responses in antigen- and exercise-induced dual asthmatic responses.