Clinical use of tricyclic antidepressants

Tricyclic antidepressants are extremely valuable drugs when they are used in suitable patients, principally those suffering from endogenous depressions. Diagnosis of depression is of major importance in determining the nature of treatment to be used. Differences between most tricyclics are minor for the most part, involving different degrees of sedative or anticholinergic properties. With the exception of doxepin, they are about equally effective in blocking the amine pump mechanism, which is believed to be the pharmacologic action most pertinent to their antidepressant action. A wide range of dose must be explored if patients are to be treated properly. For the most part, doses are defined empirically, either by alleviation of depression or by intolerable side effects. Dosage schedules should be flexible initially but during therapeutic and maintenance periods, single daily doses are possible. Maintenance doses should be reduced to the lowest consistent with continued relief. Treatment should be brief if the episode of depression is the first and is not severe, but may be prolonged for years in patients with a history of frequent and severe recurrences of depression. Other drugs may sometimes be required, and psychological approaches to treatment are always required. ECT should be available for selected instances of severe depression. The hazards of tricyclics are well known and generally are extensions of known pharmacologic effects. Careful prescribing of these drugs can minimize the consequences of suicidal or accidental overdose.