Cardiovascular effects of therapeutic doses of tricyclic antidepressants: importance of blood level monitoring.

The cardiovascular effects of therapeutic doses of tricyclic antidepressants are reviewed and their clinical significance discussed. At standard therapeutic doses these antidepressant drugs produced small changes in heart rate and several intervals of the EKG in some patients, but clinically significant effects on the EKG are usually seen only in patients with high blood levels of the drugs; these high plasma levels are often above those needed for therapeutic antidepressant effects. In contrast, the orthostatic hypotension induced by antidepressants usually occurs at dosages and blood levels within the therapeutic range, and, therefore, this side-effect may be of greater clinical significance in standard clinical treatment with antidepressants. A review of recent studies suggest that adequate doses of antidepressants may be used safely in geriatric depressed patients and in many patients with stable preexisting cardiac disease. However, more frequent monitoring of plasma levels of antidepressants and EKGs may be particularly important in these groups of patients.