Alpidem, a novel anxiolytic drug. A double-blind, placebo-controlled study in anxious outpatients

The anxiolytic activity of alpidem (150 mg/day) and its effects on psychomotor performances were compared with placebo in 60 outpatients. The trial was a double-blind, parallel group, and the two treatments were administered orally in three divided doses for 3 weeks. Eighteen male and 42 female patients (mean age, 39.6 years) suffering from generalized anxiety or adjustment disorder with anxious mood of at least 1-month duration entered the trial at the end of a 1-week placebo run-in period designed to exclude early placebo responders. Efficacy was assessed with the Hamilton rating scale for anxiety (HRSA), the state-trait anxiety inventory (STAI x 1: anxiety as state), a visual analogue scale (VAS), and clinical global impression (CGI). Psychomotor performance was assessed by the digit symbol substitution test (DSST). Alpidem was significantly more effective than placebo in decreasing the severity of anxiety, both in the physician's judgment [total HRSA (p = 0.007), psychic symptoms (p = 0.0040), somatic symptoms (p = 0.0002)] and in the patients' evaluation [STAI x 1 (p = 0.0001) and VAS (p = 0.0003)]. Psychomotor performance was improved by both treatments; there was no difference between results with alpidem and placebo at the DSST (p = 0.2801), but the improvement was almost twofold on alpidem. Side effects were negligible with both treatments and the efficacy index, obtained from the CGI, was significantly better with alpidem than with placebo after day 7 (at least p less than 0.03).