COMPARISON OF THE RESIDUAL EFFECTS AND EFFICACY OF SHORT-TERM ZOLPIDEM, FLURAZEPAM AND PLACEBO IN PATIENTS WITH CHRONIC INSOMNIA

This multicentre, double-blind, randomised, placebo-controlled, parallel group study compared the next-day residual effects, hypnotic efficacy and sleep staging effects of zolpidem 10 and 20mg with those of placebo in patients with chronic insomnia. Flurazepam 30mg was used as a positive control for residual effects. Patients completed written and computerised performance tests [Digital Symbol Substitution Test (DSST) was the primary outcome measure], and their sleep was evaluated polysomnographically and subjectively. After treatment with zolpidem for 3 consecutive nights, the change from baseline in number of correct responses on the next-morning DSST or Symbol Copying Test (SCT) was not different to that recorded in placebo-treated patients. Next-day performance was impaired every day after treatment with flurazepam. As measured by objective and subjective criteria, both zolpidem and flurazepam were effective hypnotics. Sleep stages were affected more by flurazepam than by zolpidem. The incidence of treatment-emergent adverse events was approximately the same for zolpidem 10mg, flurazepam and placebo. The 20mg dose of zolpidem (twice the therapeutic dose) was associated with a higher incidence of adverse events. It was concluded that no next-day residual effects are associated with nightly intake (3 nights) of the recommended dose of zolpidem. At this dose, zolpidem was an effective and safe hypnotic.