THE EFFECT OF PROPRANOLOL ON AIRWAY RESISTANCE

The effect of propranolol on the airway resistance (AWR) ofeighteen normal and seven asthmatic subjects has been studiedby whole body plethysmography. In normal subjects there wasa significant mean rise in AWR which was never accompanied byany respiratory upset. In asthmatic subjects there was a greatermean rise in AWR which usually resulted in dyspnoea and occasionallywheezing. In nine subjects, the studies were repeated afterthe prior administration of atropine which almost completelyabolished the rise in AWR after propranolol in normal subjectsand markedly reduced the rise in asthmatic subjects. The modeof action of propranolol in producing bronchoconstriction isdiscussed and the protective effect of atropine is stressed. ^* Present address: Department of Anaesthesia, University ofGlasgow, Western Infirmary, Glasgow, W.2.