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, parall el group study compared the next-day residual effects, hypnotic effica cy and sleep staging effects of zolpidem 10 and 20mg with those of pla cebo 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 poly somnographically and subjectively. After treatment with zolpidem for 3 consecutive nights, the change from baseline in number of correct res ponses on the next-morning DSST or Symbol Copying Test (SCT) was not d ifferent to that recorded in placebo-treated patients. Next-day perfor mance was impaired every day after treatment with flurazepam. As measu red by objective and subjective criteria, both zolpidem and flurazepam were effective hypnotics. Sleep stages were affected more by flurazep am than by zolpidem. The incidence of treatment-emergent adverse event s was approximately the same for zolpidem 10mg, flurazepam and placebo . The 20mg dose of zolpidem (twice the therapeutic dose) was associate d 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 e ffective and safe hypnotic.