Combined effect of nifedipine and diltiazem on methacholine-induced bronchoconstriction in asthmatic patients.

Calcium blockers alter airway hyperreactivity. We studied the effect of either 60 mg diltiazem or 20 mg nifedipine and their combination on the airway response to methacholine-induced bronchoconstriction. Compared with placebo or diltiazem, nifedipine significantly raised the PC20. When diltiazem was given alone, it had no effect on the airway but, when given with nifedipine, it significantly raised the PC20 to methacholine. The effect was superior to any of the other treatments given. This study supports the concept of combining two different calcium blockers in the treatment of bronchial asthma.