ABSTRACT
Isoprenaline (isoproterenol) is a potent ß-adrenoceptor agonist with very little effect at a-adrenoceptors. As a result it is chronotropic and inotropic, as well as being a potent vasodilator. Isoprenaline therefore produces an increase in cardiac output with a fall in diastolic and mean arterial pressure. Its strong ß-adrenoceptor agonist action has led to its use in the treatment of asthma, where it is a potent bronchodilator. However, its use in asthma has been limited by its tendency to produce cardiac arrhythmias and has been superseded by the development of the specific ß2 agonists. A simplified summary of the effects of these drugs is given in Table 23.11.
