ABSTRACT
Thirty five young subjects with long standing bronchial asthma were studied for the effects of terbutaline misthaler (500 micrograms) during acute asthma. Bronchodilators were omitted for a day before the test. Ten matched controls were also studied. In all subjects, basal IgE level (ELISA), pulmonary parameters (FVC, FEV, PEFR, FEF 25-75 and FEF 75-85) and platelet activity, (platelet clumping/150 WBC on smear, platelet adhesiveness, blood recalcification time and kaolin clotting time for platelet factor3) were compared. During acute asthma, the subjects displayed IgE levels > or = 500 IU/ml (n = 33), activation of clotting (n = 30) and eosinophilia > or = 450/cmm (n = 28). These changes were not seen in normal controls. Terbutaline resulted in a reversal of airway obstruction, mainly of small airways, while the platelet hyperactivity and blood hypercoagulability were rectified (P < 0.001). It is concluded that platelet activity increases in acute asthma and is corrected by inhaled terbutaline concomittant with the relief of bronchospasm.