Effects of ethyl loflazepate (CM 6912) on sleep in normal humans

The effects of 2 mg and 4 mg of ethyl loflazepate (CM 6912), a new anxiolytic benzodiazepine, on sleep were studied in 12 healthy male subjects. Polygraphic recordings were made for 6 consecutive nights from each subject. An inert placebo was given on the first 3 nights and on the sixth night, and 2 mg or 4 mg of CM 6912 was administered on the fourth and fifth nights to 6 subjects, respectively. The drug and placebo were administered orally 30 min after supper, and the record of polysomnograms started at 22:30 hr and continued until the natural awakening of the subjects the next morning. The polysomnograms were evaluated by computerized automatic analysis using the method of interval histogram. Both doses of CM 6912 increased total sleep time, and reduced sleep latency and total awakening in a dose-dependent manner. Both doses slightly decreased stage 1 sleep, significantly increased stage 2 sleep, but slightly decreased stages 3, 4 and REM sleep. These changes continued into the sixth recovery night. No obvious changes were observed in subjective assessments after administration of CM 6912. These results suggest that CM 6912 is an efficacious compound and has minimal adverse effects on sleep.