Abstract

A year ago we discussed pronethalol (Alderlin - ICI), the first clinically useful blocking agent for adrenergic beta receptors.¹ Pronethalol has two serious drawbacks: therapeutic doses often cause unwanted effects, and prolonged high doses induce tumours in mice. It was therefore advisable to reserve the drug for acute life-endangering conditions, particularly in the management of phaeochrome tumours and the treatment of certain arrhythmias. As we foreshadowed,¹ pronethalol has now been replaced by a related drug, propranolol (Inderal - ICI), which is not carcinogenic in mice² and other experimental animals, and has a much greater therapeutic ratio.