Electrocardiogram changes and therapeutic desipramine and 2-hydroxy-desipramine concentrations in elderly depressives.

ECG parameters in elderly depressed in-patients were assessed during routine desipramine treatment. Significant changes (prolonged PR and PRS intervals and a decreased QTc interval) were found, related only to steady state concentrations of desipramine's major metabolite--2-hydroxy-desipramine. Potentially clinically significant changes developed in 40% of the patients. All serum drug concentrations were within therapeutic limits. Previous assurances about desipramines's cardiac safety in the elderly may need to be re-evaluated.