Pharmacologic profile and efficacy of venlafaxine.

Venlafaxine is a structurally novel phenylethylamine agent with antidepressant properties. The preclinical profile suggests that it will be as effective as the tricyclic antidepressants (TCAs) with few significant effects on the neuroreceptors that mediate many of the side effects common with the TCAs. Venlafaxine has been studied in more than 2500 patients in clinical trials; its efficacy has been evaluated in more than 700 venlafaxine-treated patients in six placebo-controlled trials (five in out-patients and one in in-patients). These studies used a wide range of doses (25-375 mg/day) and different dose regimens (t.i.d. and b.i.d). The results of these studies clearly establish that venlafaxine is significantly more effective than placebo. In the two studies that used doses of 375 mg/day, a significant difference from placebo was observed on the Montgomery- Asberg Depression Rating Scale (MADRS) at the earliest time points assessed, after 4 days of treatment in the in-patient study and after 1 week of treatment in the out-patient study. Venlafaxine also appears to be as effective as some reference antidepressants. A positive dose-response effect has been demonstrated with doses of up to 375 mg/day, with a minimum effective dose of 75 mg/day.