Effect of calcium antagonists on allergen-induced asthma.

The protective effect of inhaled verapamil (estimated dose 2 . 4 mg) and sub-lingual nifedipine (20 mg) against allergen-induced asthma were each assessed by the administration of calcium antagonists 30 min before bronchial provocation tests using Dermatophagoides pteronyssinus extracts on eight young perennial asthmatics. Neither drug changed the basal forced expiratory volume in one second (FEV1) or the provocation dose of allergen required to cause a 20% fall in FEV1 (PD20 . FEV1). That calcium antagonists are ineffective in preventing allergen-induced asthma suggest indirectly that mechanism other than mediator release from mast cells may also be involved.