Sotalol intoxication, two patients with concentration-effect relationships

Abstract

Two adult patients ingested an overdose of 2.4 g and 8.0 g of sotalol hydrochloride, respectively, i.e. 7-25 times the mean daily dose. Certain signs as bradycardia and hypotension were similar to those described for other beta-blocking agents. In addition to these, however, both patients had severe cardiac tachyarrhythmias and a considerably prolonged QT-interval in their electrocardiogram. The decline of serum sotalol concentrations followed first-order kinetics with the elimination half-life of 13-15 hours. There was a good correlation between the serum sotalol concentration and the prolongation of the QT-interval. Sotalol differs from other beta-blocking agents in its effects on the action potential of the ventricular muscle and Purkinje fibers of the heart. This is likely to explain the different symptoms and findings of sotalol intoxication compared to those seen in connection with other beta-blocking agents.