Venlafaxine, a new antidepressant drug, inhibits the synaptic reuptake of both serotonin and norepinephrine. As a result of this dual mechanism of action, venlafaxine is effective against a broad range of depressive conditions, both mild-to-moderate and severe, whether occurring in inpatients or outpatients. The promise shown in preclinical studies was first supported by a series of open, noncomparative studies and then by placebo-controlled, double-blind trials. Venlafaxine was found to be significantly better than placebo in reducing depression, as measured on a variety of psychometric scales, and it was noted that in this respect it was at least as effective as, and often more effective than, comparator antidepressants, including imipramine, clomipramine, trazodone and fluoxetine. In longer-term treatment, venlafaxine has been shown to reduce the frequency of relapses in comparison with placebo treatment. Also in long-term use, venlafaxine has been associated with a significantly greater percentage of responders than seen with imipramine. A characteristic of venlafaxine is its early onset of action, a feature which may be related to its dual mode of action; efficacy has been reported within the first week of treatment when a rapid dose escalation regimen was employed. The clinical efficacy of venlafaxine appears, on present evidence, not to be affected by the age or sex of the patient, nor is it lessened by concomitant melancholia, psychomotor retardation or agitation, or anxiety. The drug appears equally effective against mild-to-moderate depressive illness and depression which is severe, of long duration, and/or refractory to other antidepressant medications. It is concluded that venlafaxine is an effective antidepressant agent with a possible short latency to onset of its clinical action, which may be used in a wide range of depressive conditions.
