7 groups of 3 healthy male volunteers each, at the age of 21--27 years received various doses of Lormetazepam (0.0635 to 4.0 mg/70 kg). -- 2. The drug was injected intravenously during 60 s. Before, during and up to 4 hours after the injections the EEG, eye-movements, ECG and respiration was recorded and blood pressures measured at given time intervals. -- 3. The vigilo-somnograms showed after the injections a change in the EEG-stages, indicating a reduction of alertness, transitions into reduced wakefulness or beginning stages of sleep. Corresponding to clinical signs one can speak with i.v. applied doses of 0.0635 to 0.5 mg/70 kg of tranquilizing, with 1 mg/70 kg of sedative and with 2--4 kg of hypnotic effects. There has been a good dosage-efficiency relation. -- 4. Side-effects or unwarranted symptoms have not been seen during the clinical observations.
