Nifedipine in chronic bronchial asthma: a randomized double-blind crossover trial against placebo.

Calcium-channel blockers such as verapamil and nifedipine have been shown to inhibit exercise-induced asthma as well as acutely induced bronchoconstriction, but little is known of their chronic effects, if any, on bronchial asthma. Nifedipine, 60 mg/day for 3 weeks, was compared to placebo in a double-blind randomized crossover study, as an addition to the usual treatment of 11 patients with severe chronic bronchial asthma. Nifedipine decreased the weekly duration of the attacks (102 +/- 34 vs 193 +/- 49 min, p less than 0.05), the number of betamimetic puffs inhaled per week (13 +/- 3 vs 18 +/- 4, p less than 0.05), and the duration of intercritical dyspnoea (7.9 +/- 3.9 vs 15.9 +/- 2.3 h, p less than 0.05) without significantly changing the number of asthma attacks (4.8 +/- 1.2 vs 4.7 +/- 1.7, NS). Nifedipine did not significantly change basal respiratory function, nor did it change heart rate or blood pressure. Side effects were noted in 5 patients taking nifedipine, leading to a decrease in the dosage to 30 mg per day in 3, and in one patient taking placebo. In this study nifedipine had essentially subjective effects, but these warrant a longer-term study of nifedipine or other calcium antagonists in the treatment of bronchial asthma.