A double-blind comparison between nitrazepam, lorazepam, lormetazepam and placebo as preoperative night sedatives

Benzodiazepines are used as hypnotics to reduce anxiety and give a good night's sleep on the night prior to surgery. In a double-blind procedure, patients were given either lorazepam (2 mg or 4 mg), lormetazepam (1 mg or 2 mg), nitrazepam 10 mg or placebo. Measures were taken of sleep, anxiety, memory and after-effects. There was no evidence that the drugs reduced anxiety, nor evidence of amnesia. Quality and length of sleep was shown to be better for nitrazepam (P less than 0.05), lorazepam 2 mg (P less than 0.05) and lorazepam 4 mg (P less than 0.01), compared with placebo. However, significantly higher ratings of clumsiness and confusion as after-effects were found with nitrazepam (P less than 0.05), and clumsiness (P less than 0.005), slurred speech and blurred vision (P less than 0.01), sleepiness, nausea, weakness and confusion (P less than 0.05) with lorazepam 4 mg. It was concluded that lorazepam 2 mg produced the greatest net benefit.