Selective cardiac sympathetic blockade as an adjunct to bronchodilator therapy.

Attention has recently been directed to the possible lethal effect of aerosol sympathomimetic agents in the treatment of bronchial asthma (Speizer, Doll, Heaf and Strang, 1968), death being attributed to an excitatory action on the heart. Animal studies indicate that practolol (I.C.I. 50,172, Eraldin) specifically blocks cardiac beta-adrenergic receptors, preventing arrhythmias or other alterations in cardiac function, but does not interfere with the bronchodilator actions of sympathetic amines (Dunlop and Shanks, 1968). We have investigated the ability of I.C.I. 50,172 to protect the hearts of asthmatic patients from the excitatory action of sympathomimetic drugs.