Propranolol and ventricular arrhythmias with halothane

The successful treatment of ventricular arrhythmias occurring during anasthesia was reported by Payne et al. 1 and Johnstone2 who used pronethalol, a B-adrenergic blocking drug. The disadvantages of pronethalol, namely the production of lightheadedness, inco-ordination leading to nausea and vomiting and a carcinogenic effect in mice, led to the investigation of other similar compounds, Black et al. 3 One of these, Compound ICI 45,520, (now referred to as propranolol or by the trade name ‘Inderal’) was found to have a therapeutic ratio about ten times that of pronethalol and was free from carcinogenic effects in mice. The following investigation was undertaken to see whether or not propranolol was effective in the treatment of ventricular arrhythmias occurring during halothane anzsthesia.