Prazosin, an alpha 1-adrenoceptor antagonist, partially inhibits exercise-induced asthma.
The effect of prazosin, a potent and specific alpha 1-adrenoceptor antagonist given by inhalation (total nebulized 2 mg) was compared with placebo in a double-blind randomized study of 10 atopic asthmatic children. Prazosin significantly (p less than 0.01) reduced the severity of post-exercise bronchoconstriction (maximum fall in peak expiratory flow after exercise 21.4% +/- SEM 6.3% after prazosin compared with 42.5% +/- 7.3% after placebo). This protective action of prazosin suggests that activation of alpha 1-adrenoceptor may be involved in the pathogenesis of exercise-induced asthma either by facilitation of mast-cell mediator release or by direct contraction of bronchial smooth muscle. Prazosin did not significantly change resting bronchomotor tone or histamine-induced bronchoconstriction, suggesting no effect on bronchial smooth muscle contractility.
D000293:Adolescent; D000316:Adrenergic alpha-Agonists / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D001250:Asthma, Exercise-Induced / Q000188:drug therapy*; D002648:Child; D002986:Clinical Trials as Topic; D005260:Female; D005541:Forced Expiratory Volume; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D008297:Male; D010366:Peak Expiratory Flow Rate; D010919:Placebos; D011224:Prazosin / Q000627:therapeutic use*; D011799:Quinazolines / Q000627:therapeutic use*; D011897:Random Allocation; D014797:Vital Capacity
D000316:Adrenergic alpha-Agonists; D010919:Placebos; D011799:Quinazolines; D006632:Histamine; D011224:Prazosin