Current antidepressant drugs: their clinical use

Depression is not only a common disorder, but also one that is readily treatable. Antidepressant drugs play a major role in treatment, although concurrent use of electroconvulsive therapy or psychotherapy may be indicated for some patients. Antidepressant drugs have been most specifically beneficial for patients with 'endogenous' depressions, but they should be used whenever this type of depression cannot be definitely ruled out. Besides the older tricyclic antidepressants and monoamine oxidase inhibitors, a new 'second generation' group of drugs is now available. Although these drugs offer no great therapeutic advantages over the older ones, they may prove to have a more acceptable profile of side effects, may act more quickly, and may show less cardiotoxicity with overdoses. Whether one can classify depression pathogenetically according to various biological markers, such as urinary excretion of the norepinephrine metabolite, 3-methoxy-4-hydroxy phenylglycol, is still uncertain. At present, the choice of antidepressant drug for an individual patient is largely empirical. Besides being useful for treating depression, antidepressants may be used for treating enuresis, chronically painful states, obsessive-compulsive-phobic states, acute panic attacks and cataplectic attacks in narcoleptics. Many studies have tried to define a therapeutic range of plasma concentrations of these drugs, so as to afford a better basis for dosing, but routine monitoring of drug plasma concentrations is seldom needed; the primary indication for doing so would be in the patient who has received what should be an adequate dose but who is still unresponsive. The value of maintenance treatment with antidepressants has been clearly established; the pattern it takes is best determined by the natural history of the disorder in individual patients. Most drug interactions with antidepressants are pharmacodynamic in nature and can be managed by adjusting doses. Pharmacokinetic interactions with various sympatholytic antihypertensive drugs, such as guanethidine, methyldopa and clonidine, are rare but may be serious. Patients with depression may be spared a considerable amount of discomfort, morbidity, and possibly mortality, by judicious use of antidepressant drugs and the other treatments currently available.