Of 20 volunteers, five were given intravenous Diazemuls 15 mg over 15 seconds, and three groups of five were given lormetazepam 2 mg intravenously over 10, 20 and 60 seconds, respectively. Laryngeal reactivity and psychomotor function were tested at intervals from prior to injection until 4 hours after injection. For equivalent degrees of depression of psychomotor function, lormetazepam depressed the laryngeal reflex less than Diazemuls (p = 0.004). Lormetazepam give over 60 seconds depressed the laryngeal reflex more than when given over 10 seconds (p = 0.008) or over 20 seconds (p = 0.048), although a significant difference was not demonstrated between the 10-second and 20-second groups. These results concur with experimental evidence that benzodiazepine receptor multiplicity exists, which allows various members of the benzodiazepine group of drugs to exhibit differing therapeutic ratios for their various effects.