RELATIVE TOXICITY OF BENZODIAZEPINES IN OVERDOSE

Objective-To assess the sedative effects in overdose of temazepam and oxazepam compared with other benzodiazepines to determine if this expl ains reported differences in fatal toxicity. Design-Cohort study of pa tients admitted with benzodiazepine poisoning. Setting-Newcastle, Aust ralia. Subjects-303 patients who had ingested benzodiazepine alone or in combination with alcohol and presented to a general hospital which served a well defined geographical area. Main outcome measures-Degree of sedation: Glasgow coma score, McCarron Score, and whether patients were stuporose or comatose. Results-Oxazepam produced less and temazep am more sedation than other benzodiazepines. Unadjusted odds ratios fo r coma with oxazepam and temazepam compared with other benzodiazepines were 0.0 (95% confidence interval 0.0 to 0.85) and 1.86 (0.68 to 4.77 ) respectively, chi(2) = 7.08, 2df, P = 0.03. After adjustment for pot entially confounding effects of age, dose ingested, and coingestion of alcohol, the odds ratios were 0.22 (0.0 to 1.43) for oxazepam and 1.9 4 (0.57 to 6.23) for temazepam. Similar results were obtained for othe r measures of sedation. Conclusions-These results were in accordance w ith fatal toxicity indices derived from coroners' data on mortality an d rates of prescription. The relative safety of benzodiazepines in ove rdose should be a consideration when they are prescribed.