Clinical course, serum concentrations and elimination rate in a case of massive sotalol intoxication

A young woman had been on antiarrhythmic treatment with sotalol 80-160 mg daily for three years because of ventricular tachycardia. After a quarrel she ingested an overdose of sotalol, estimated to be 13-14 g, and was immediately brought to hospital, where the first ECG was taken 25 minutes after the ingestion. The clinical course, including the relationship over time between pronounced bradycardia, QT prolongation and malignant ventricular tachyarrhythmias is described. Serum concentrations were obtained regularly between 11 and 54 hours after the ingestion. After initially very high levels, the concentrations decreased in a strictly exponential manner to arrive at therapeutic concentrations 39 hours after the ingestion. Calculations revealed that over 12 g of sotalol was absorbed into the circulation, while the half life was 9.2 h and the oral clearance 294 mg min-1. The heart rate normalized about 24 hours after the repolarization variables, which supports the opinion that the class III action of sotalol is unrelated to the beta-blockade. In sotalol intoxication, malignant tachyarrhythmias appearing during excessive prolongation of the QT interval, most often in combination with hypokalemia, ethanol intoxication or concomitant antiarrhythmic treatment, may need emergency defibrillation but seem to disappear within a few hours. Thus, while massive sotalol intoxication may be fatal, early treatment promotes a successful outcome even when very high doses have been ingested.