Differential effects of nifedipine and diltiazem on methacholine-induced bronchospasm in allergic asthma.

The protective effect of nifedipine and diltiazem on methacholine-induced bronchoconstriction was studied in 12 allergic asthmatic patients. Nifedipine significantly but weakly attenuated airway reactivity to methacholine, whereas no protective effect was shown by diltiazem. We conclude that the two calcium antagonists have different effects on human airways. Furthermore, our results suggest that the action of nifedipine on methacholine-induced bronchospasm is too weak to justify its recommendation as therapy.