[Clinical study of propofol in male volunteers]

A clinical phase 1 study of intravenous anesthetic, propofol, was carried out in 6 male volunteers. Propofol, 1, 2, and 2.5 mg.kg-1, was administered intravenously. Anesthetic effects and effects on vital signs, such as blood pressure, heart rate, respiratory rate and body temperature, were investigated. Any adverse effects or abnormal laboratory findings were also investigated. Venous blood samples were obtained frequently for 12 hours to measure blood propofol concentrations. One volunteer out of 6 lost consciousness with 1 mg.kg-1 and the remaining with 2 mg.kg-1 within 1.5 min. In 2 volunteers the duration of anesthesia was inadequate for clinical practice with 2 mg.kg-1. Therefore, 2.5 mg.kg-1 was given. Rhythmic high voltage slow waves appeared immediately after the loss of consciousness in EEG and then basic activity changed to 11 approximately 16 Hz, 30 approximately 60 microV. Blood pressure decreased and heart rate increased but no profound hypotension was observed. Body temperature decreased. No adverse effect, such as laryngospasm, bronchospasm or hiccough, occurred. Laboratory test showed no abnormal result. Pharmacokinetic analysis was carried out using a 3 compartment open model. The half time of distribution phase, 2.6 min, was short, and total clearance, 1.68 l.min-1, was high. We conclude that the proper induction dose of this agent is 2 approximately 2.5 mg.kg-1, which is similar to the values previously reported in European investigations, and that this agent is safe and useful for induction of anesthesia.