Effects of calcium channel blockade on histamine induced bronchoconstriction in mild asthma.

Inhalation histamine dose-response curves were constructed 15 minutes after inhalation of saline placebo or verapamil (4 mg) for eight patients with mild atopic asthma in a double blind, random manner. No significant change in baseline specific airways conductance occurred after inhalation of verapamil, though there was a significant decrease in sensitivity to histamine (increase in threshold of response) (p less than 0.01). There was, however, an associated significant increase (p less than 0.01) in the slopes of the subsequent histamine dose-response curves.