Cardiovascular effect of imipramine and nortriptyline in elderly patients

Cardiovascular effects in elderly depressed patients (age 62-78 years) treated with imipramine (N = 11) or nortriptyline (N = 10) were recorded by monitoring of heart rate, blood pressure, systolic time intervals, standard ECG and 24-h ECG. The two drugs exhibited distinctly different cardiovascular reactions. The use of imipramine was severely limited by orthostatic hypotension occurring at subtherapeutic plasma levels, which resulted in falls with fracture in two patients. In contrast, nortriptyline at therapeutic drug levels did not significantly influence orthostatic blood pressure regulation. Nortriptyline caused moderate changes in systolic time intervals, indicating impairment in myocardial contractility. This effect was not seen with imipramine, but a majority of the patients did not reach therapeutic plasma levels because of blood pressure reactions. Neither imipramine nor nortriptyline induced changes in cardiac conduction time measurements or arrhythmias. In addition to the blood pressure reactions, the use of imipramine was complicated by dose dependent kinetics.