The immediate and short-term effects of corticosteroids on cholinergic hyperreactivity and pulmonary function in subjects with well-controlled asthma.

We investigated the immediate effect of corticosteroids on pulmonary function (FEV1 and forced expiratory flow measured between 25% and 75% of vital capacity) and methacholine airway reactivity during a period of 8 hours after an intravenous bolus of 6-methyl-prednisolone (1 mg/kg) or saline placebo administered in a double-blind, crossover schedule in 12 patients with well-controlled asthma. The short-term effect of corticosteroids was also studied with bronchial reactivity to methacholine and pulmonary function measured before and at the end of 8 days of 6-methyl-prednisolone therapy (32 mg once a day, orally) in a group of six treated subjects as well as in a control group. There were no immediate or short-term effects from 6-methyl-prednisolone on bronchial response to inhaled methacholine. After 8 days of corticosteroid administration, forced expiratory flow measured between 25% and 75% of vital capacity significantly increased in the treated group (p less than 0.025). We concluded that "primary hyperreactivity" appears to be insensitive to an intravenous bolus or 8 days of treatment with oral corticosteroids and that the improvement in respiratory function is slight and slowly evolving in subjects with well-controlled asthma.