title: Effect of penbutolol and propranolol on normal airway response to salbutamol.
abstract: The specific airway conductance (sGaw) response of eight normal men to inhaled salbutamol, 200, 600, and 1800 micrograms, was measured on 3 separate days. On each occasion subjects received either placebo, long-acting propranolol (160 mg), or penbutolol (40 mg) orally in a double-blind manner after baseline lung function determination. After placebo, mean sGaw rose from a baseline of 2.07 +/- 0.15 to 2.81 +/- 0.25 kPa-1 X sec-1 after 200 micrograms salbutamol. There was little further airway dilation with higher doses of salbutamol. With long-acting propranolol, there was no significant airway dilation after 200 micrograms salbutamol but there was after 600 and 1800 micrograms inhaled salbutamol; baseline sGaw rose from 2.02 +/- 0.17 to 2.70 +/- 0.28 and 2.95 +/- 0.32 kPa-1 X sec-1. Penbutolol prevented any significant airway dilation with all doses of salbutamol. Penbutolol at the doses used appears to be a more potent blocker of beta 2-receptors than does propranolol.
mesh_terms: D000328:Adult; D000420:Albuterol / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001980:Bronchi / Q000187:drug effects*; D004106:Dilatation; D004311:Double-Blind Method; D004347:Drug Interactions; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D010394:Penbutolol / Q000494:pharmacology*; D011412:Propanolamines / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*
chemical_list: D011412:Propanolamines; D010394:Penbutolol; D011433:Propranolol; D000420:Albuterol