Sleep and wake after benzodiazepine hypnotics: a 20-hour EEG comparison of lormetazepam and flunitrazepam.

In an electropharmacokinetic study, the effects of lormetazepam and flunitrazepam were compared by the means of a sleep EEG and waking EEG during the following daytime. At a 1-week interval, 6 normal subjects received at random either 2 mg lormetazepam or 2 mg flunitrazepam in a double-blind, crossover fashion. Sleep EEG was recorded throughout the night; 6-min EEG samples were recorded every hour during 10 hours on the following daytime for spectral analysis. Night sleep after flunitrazepam showed lower Stage IV sleep than after lormetazepam. During daytime, only flunitrazepam induced an increased percentage of beta 2 frequencies, which remained above baseline up to 10 hours after awakening, indicating a prolonged impregnation time. This study permitted comparison of the relative intensity and duration of these two benzodiazepines: lormetazepam appeared to be a short-acting hypnotic while flunitrazepam displayed longer modification of the brain electrical activity.