EFFECTS OF ZOLPIDEM AND TRIAZOLAM ON ALL-NIGHT SLEEP EEG IN NORNAL VOLUNTEERS - ASSESSING THE SLEEP STAGES BY THIRDS OF THE NIGHT -

Efficacy of zolpidem in insomnia

The efficacy of zolpidem, a non benzodiazepine hypnotic agent with a short elimination half life, was reviewed, analysing more than 50 international clinical trials published since 1986. The hypnotic activity of zolpidem has been explored in different patient populations including normal volunteers, general practice outpatients and psychiatric out- or in-patients with varying sleep disorders; both transient and chronic. Assessment methods used have included objective and subjective measures of hypnotic efficacy for different treatment durations, with results confirming that 10 mg is superior to placebo. Zolpidem was shown to be superior in most trials on sleep parameters such as total sleep time, sleep onset latency and nocturnal awakenings, but total REM sleep and REM latency were usually unmodified. Zolpidem maintained normal sleep physiology as demonstrated by the preservation of slow wave stages and no, or minimal, effects on sleep architecture after abrupt discontinuation. Consequently, 10 mg is the recommended dose for the short-term treatment of insomnia in the non-elderly; in elderly patients 5 mg has been shown to be effective at inducing sleep whilst giving an optimum safety profile.

EEG profile of intravenous zolpidem in healthy volunteers

Zolpidem is an imidazopyridine which binds specifically to the omega 1 receptor. Zolpidem demonstrated potent hypnotic activity at a dose of 10 mg. Pharmacodynamics and pharmacokinetics of zolpidem were studied after daytime administration in a randomised, double-blind, placebo-controlled, cross-over trial. Single doses of zolpidem (10 mg IV as a 3-min infusion and 20 mg orally) and placebo were firstly tested in 12 healthy young male volunteers. Two other doses (5 mg IV and orally) were then evaluated in 6 out of these 12 subjects. EEG (4 leads = Fp2-T4, Fp1-T3, T4-02 and T3-01), and Stanford Sleepiness Scale (SSS) were measured up to 5 h postdosing. Blood samples were also collected up to 24 h. The time course of the hypnotic activity of zolpidem, assessed by the score obtained on SSS, showed a similar profile whatever the route or the dose administered: slightly earlier onset after IV but sedative scores were reached at 30 min and the effect peaked between 1 and 1.5 h and lasted 4 h in both conditions. The EEG profile of zolpidem was characterised by a decrease of alpha activity and an increase in delta and in beta activity. The effect on beta activity was marked within the first hour and then disappeared. The time course of delta and alpha activities indicated a rapid onset (10 min after IV, 30 min after oral route) and a duration of 3-4 h. The amplitude of these relative EEG changes and their duration were independent of the route of administration and the dose administered. AUC and Cmax increased proportionally to the administered dose and elimination half life (2h), clearance and volume of distribution did not change according to the dose or the route of administration.(ABSTRACT TRUNCATED AT 250 WORDS)