Alpidem: Lack of sedative effect on psychomotor performance in therapeutic doses

This is a randomised, double blind, cross‐over, placebo‐controlled study carried out in 12 healthy young male volunteers. It consisted of six test days separated by two week wash‐out periods. The objective was to compare the potential sedative effects of 3 single oral doses of alpidem (50 mg, 100 mg and 200 mg) versus diazepam (10 mg and 15 mg). Pharmacodynamics were assessed by objective psychometric tests (critical flicker fusion, choice‐reaction time, manual dexterity, digit span) and subjective evaluation (visual analogue scales) before then 2 h, 4 h, 8 h and 24 h post‐dose. Alpidem in dosages of 50 mg and 100 mg did not impair alertness or psychomotor performance; with 200 mg, psychometric tests and visual analogue scales demonstrated sedative effects 2 h post‐dose. In contrast, diazepam in a therapeutic dosage (10 and 15 mg) produced similar impairments of vigilance and psychomotor performance as alpidem 200 mg, indicating a lack of dissociation between anxiolytic and sedative effects.