Midazolam and fat-emulsion diazepam as intramuscular premedication. A double-blind clinical trial.

Sixty female patients were given, in random order, under double-blind conditions, either midazolam or fat-emulsion diazepam, intramuscularly, as premedication, 1 h before general anaesthesia. The dose of midazolam used was 0.13 mg/kg and that of diazepam 0.17 mg/kg. The degree of sedation, mood of the patient, and time at which onset of effect was perceptible were assessed before induction of anaesthesia, together with skin temperature and concentrations of midazolam or diazepam in plasma. Patients were interviewed postoperatively to discover their subjective evaluation of the premedication and to assess its amnesic effects. Midazolam was significantly superior (P less than 0.05) to diazepam as regards sedation. There were no differences in effects on mood of the patients between the two groups. Sixteen patients in the diazepam group and four in the midazolam group had no perception of onset of effect. The difference is significant (P less than 0.01). The skin temperature was, on average, 2 degrees C higher in the midazolam group than in the diazepam group (P less than 0.005). The mean plasma concentration was 67.8 +/- 24.5 micrograms/l in the midazolam group and 44.8 +/- 25.7 micrograms/l in the diazepam group. In only two cases was the concentration of diazepam above 100 micrograms/l (arbitrarily defined as the minimum sedative concentration). Subjective evaluation of efficacy significantly (P less than 0.002) favoured midazolam. Local pain was evident in two patients in the diazepam group, and three patients experienced nausea immediately after administration of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)