Effect of clenbuterol on peripheral airway obstruction in bronchial asthma.
A study was carried out in 6 patients with bronchial asthma to investigate the effects of clenbuterol, a beta 2-sympathomimetic bronchodilator, on peripheral airway obstruction. The basal lung functions of the patients were almost within normal range in both vital capacity (VC) and forced expiratory volume in 1 second (FEV1), but their maximal flow rates were lower in effort-independent phase of both maximal expiratory flow volume (MEFV) curve and partial expiratory flow volume (PEFV) curve. Furthermore, they demonstrated marked basal frequency dependence of dynamic compliance [CL,dyn]. Oral administration of clenbuterol (40 micrograms) produced a significant increase in the maximal flow in effort-independent phase of both MEFV and PEFV curves, and markedly decreased frequency dependence of CL,dyn in comparison with the baseline values, while it improved both VC and FEV1 to a lesser extent. These results suggest that clenbuterol preferentially reduced the peripheral airway obstruction in bronchial asthma.
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D001784:Blood Gas Analysis; D001794:Blood Pressure; D002976:Clenbuterol / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D004983:Ethanolamines / Q000627:therapeutic use*; D005260:Female; D005540:Forced Expiratory Flow Rates; D006801:Humans; D008297:Male; D008875:Middle Aged; D011674:Pulse; D014797:Vital Capacity
D004983:Ethanolamines; D002976:Clenbuterol