Open comparative study of the efficacy, safety and tolerability of midazolam versus thiopental in induction and maintenance of anaesthesia.

In a multicentre study, 145 adult Nigerian patients presenting with diverse conditions (falling into ASA1 or ASA2 classification) for short surgical procedures (< 1 hour) were given either midazolam (0.15-0.20 mg/kg) or thiopentone (4-6 mg/kg) intravenously for induction of anaesthesia. Study population consisted of 58 male and 89 female patients with a mean age of 33.5 +/- 10.42 years. The primary efficacy criteria for induction of anaesthesia was induction time measured by the time of spontaneous closing of eyes and disappearance of palpebral reflexes following injection of trial drug. For maintenance of anaesthesia efficacy was assessed by the requirement of an additional dose of the anaesthetic agent either alone or in combination with other agents in addition to N20/O2 mixture. The secondary efficacy criteria was the degree of anterograde amnesia produced by trial drug, this was assessed by memory test. Safety was assessed by the frequency of the incidence of apnoea and cardio-stability measured by changes in the haemodynamic parameters (BP and pulse). Tolerability was evaluated by incidence of phlebitis or pain at the injection site. The standard efficacy population was all the 145 patients while only 100 patients were considered evaluable for maintenance efficacy. The mean induction time was 67.28 +/- 63.36 secs and 31.28 +/- 13.01 secs for the midazolam and thiopentone groups respectively. Anaesthesia was maintained with N20/O2 alone in 47% of patients in the midazolam group compared with 28.6% of patients in the thiopentone group. The degree of anterograde amnesia was significantly more pronounced in the midazolam group than in the thiopentone group (p = 0.000).(ABSTRACT TRUNCATED AT 250 WORDS)