Effects of a new benzodiazepine derivative, ethyl loflazepate (CM6912), on the arousal level of normal humans assessed by the averaged photopalpebral reflex.

The effects of a new benzodiazepine derivative, ethyl loflazepate (CM6912), on the arousal level of normal male human subjects were investigated by use of the averaged photopalpebral reflex (PPR), the latency of which is sensitively prolonged with the lowering of the arousal level. Four doses of ethyl loflazepate, i.e., 2 mg, 4 mg, 6 mg, and 8 mg, and a placebo were administered to each subject 30 min after lunch according to a double-blind, crossover design. Ethyl loflazepate prolonged both latencies of PPR in a dose-dependent manner. The dose-response curves for both latencies, derived from the maximum prolongation, showed a definite and linear dose-response relationship. The drug action occurred within 1 h, peaked at 2.5-3 h, and continued slightly even 4 h after medication. In the subjective assessments, vagueness of thought, sleepiness, and weakness were only slightly observed. These results suggest that ethyl loflazepate could be a potent hypnotic and/or anxiolytic which possesses a relatively rapid onset of action with moderate duration and has no severe side effects.