Fatal poisonings attributed to benzodiazepines in Britain during the 1980s.

The fatal toxicity indices of benzodiazepines during the 1980s were calculated from national prescribing data and mortality statistics. The overall rate was 5.9 deaths per million prescriptions for benzodiazepines taken alone or with alcohol only, anxiolytics being less toxic than hypnotics. Diazepam appeared more toxic than average among anxiolytics (P < 0.05), and flurazepam and temazepam more toxic than average among hypnotics (both P < 0.001). It was shown that the finding for diazepam was probably explained by concurrent use of alcohol, which implies that other anxiolytics may be safer in cases where there is alcohol misuse; but the greater toxicity of flurazepam and temazepam remained unexplained. Benzodiazepines are indeed much less toxic than the barbiturates they superseded, but they are not innocuous and temazepam in particular requires further evaluation.