Clinical Pharmacology Nifedipine Protects Against Methacholine-Induced Bronchoconstriction

In an open study, 14 mild asthmat1cs underwent a methacholine chloride inhalation challenge. using a nebuliser. until FEV 1 was reduced by 40% or until 300 inhalations of 1 mgjml solution had been g1ven Withm 4 days the challenge was repeated 20 mins after patients had received a 20mg capsule of n1fed1pme sublingually

Basal FEV 1 varied less than 5% on both challenges. Sensitivity (inhalation units requ1red to produce a 20% fall in FEV 1) and reactivity (slope of the dose-response curve) to methacholine chloride were h1ghly correlated (r2 = 0.89, p < 0.001 ). N1fedipine reduced sensitivity to methacholine chlor1de from 36.7 to 61.0 units (p < 0.01) and reactivity from 2.2 to 1.1 (p < 0.02), and gave greater protect1on when basal sensitivity was higher (r = 0.59, p < 0.05). Protection was not correlated w1th react1v1ty. No pat1ents reported adverse effects.

The authors concluded that 'nifedipine protects against bronchoconstriction induced by methacholine, decreasing both the sensitivity and reactivity. Although this effect may suggest a potential benefit of its use in bronchial hyperreactivity, clinical studies will be necessary to demonstrate its value'. Perp1iia M. Pelllcer C, Marco V Resp~rat1on 51 49-57. No 1. 1987

0156-2703/87/0425-0017 j0$01.00/0 © ADIS Press INPHARMA • 25 April 1987 17