Effects of lormetazepam and of flurazepam on sleep

Nine poor sleepers of mean age 61 years took part in a double-blind, balanced order study in which, during three periods of 3 weeks, each took lormetazepam 1 mg, lormetazepam 2.5 mg, and flurazepam 30 mg. Using electrophysiological measures, sleep was found to increase by 0.75 h with each treatment condition, mainly through more of stage 2 sleep. The treatments reduced the delay to sleep and led to fewer and shorter awakenings, with little difference among the three treatments. Slow-wave sleep was reduced by flurazepam and by lormetazepam 2.5 mg. After flurazepam intake ceased, there was evidence of persisting drug effects for as long as 7 nights. In contrast, when lormetazepam 2.5 mg ceased, there was significant rebound reduction of sleep duration below baseline for up to 3 withdrawal nights, and there was a similar though non-significant trend after lormetazepam 1 mg had ceased. Wakefulness in the final 2 h of nocturnal recording during the third week of drug intake was significantly reduced below baseline by flurazepam, but was little affected by lormetazepam. The differences among the treatment conditions could be attributed to the long-persistence of flurazepam vs the more rapid elimination of lormetazepam.