Bronchodilator potential of nifedipine in vitro.

To assess the potential impact of nifedipine in asthma the effects on histamine- and metacholine-induced contractions in guinea-pig tracheal muscle were studied. Nifedipine is a physiological antagonist of these substances, but also appears to antagonize isoprenaline-induced relaxation. Further studies will be necessary to define the precise implications of these observations.