The cardiac effects of therapeutic plasma concentrations of imipramine.

The authors studied the effects of imipramine hydrochloride at plasma concentrations associated with antidepressant activity in seven patients hospitalized for severe depressive illness. They found that the drug usually produced prolongation of intraventricular cardiac conduction. Although this was generally well tolerated, the authors suggest that patients with preexisting conduction system disease may be at increased risk when taking tricyclic antidepressants. They feel that the orthostatic hypotension seen in all seven patients represents a potentially serious problem with tricyclic antidepressants. They discuss the antiarrhythmic properties associated with imipramine and significant interactions between imipramine and drugs taken by patients with cardiovascular disease.