A review of the cardiovascular effects and toxicity of tricyclic antidepressants.

The tricyclic antidepressants have potent and complex effects on the cardiovascular system, both directly and through interactions with other drugs. Through a combination of anticholinergic activity, direct myocardial depressant activity and an effect on the adrenergic neuron, they can cause a combination of arrhythmias, blood pressure abnormalities and congestive heart failure. These changes, although most common with overdose, can occur at therapeutic levels. In addition a number of drug-drug interactions can occur between the tricyclics and agents used in the treatment of cardiovascular disease, as exemplified by tricyclic antagonism of the antihypertensive effect of guanethidine. Awareness of these factors is necessary to insure proper therapeutic utilization of the tricyclics as well as to treat effectively their toxicity.