A systematic review of research examining benzodiazepine-related mortality

PURPOSE

This paper will review literature examining the association of benzodiazepine use and mortality.

METHODS

An extensive literature review was undertaken to locate all English-language published articles that examine mortality risk associated with use of benzodiazepines from 1990 onwards.

RESULTS

Six cohort studies meeting the criteria above were identified. The results were mixed. Three of the studies assessed elderly populations and did not find an increased risk of death associated with benzodiazepine use, whereas another study of the general population did find an increased risk, particularly for older age groups. A study of a middle aged population found that regular benzodiazepine use was associated with an increased mortality risk, and a study of 'drug misusers' found a significant relationship between regular use of non-prescribed benzodiazepines and fatal overdose. Three retrospective population-based registry studies were also identified. The first unveiled a high relative risk (RR) of death due to benzodiazepine poisoning versus other outcomes in patients 60 or older when compared to those under 60. A positive but non-significant association between benzodiazepine use and driver-responsible fatalities in on-road motor vehicle accidents was reported. Drug poisoning deaths in England showed benzodiazepines caused 3.8% of all deaths caused by poisoning from a single drug.

CONCLUSION

On the basis of existing research there is limited data examining independent effects of illicit benzodiazepine use upon mortality. Future research is needed to carefully examine risks of use in accordance with doctors' prescriptions and extra-medical use.

Alprazolam is relatively more toxic than other benzodiazepines in overdose

AIMS

To describe alprazolam poisoning and the relative toxicity of alprazolam compared with other benzodiazepines.

METHODS

A database of consecutive poisoning admissions to a regional toxicology service was searched to identify consecutive benzodiazepine deliberate self poisonings, which were coded as alprazolam, diazepam or other benzodiazepine. Major outcomes used were length of stay (LOS), intensive care (ICU) admission, coma (GCS < 9), flumazenil administration and requirement for mechanical ventilation. Prescription data were obtained for benzodiazepines for the study period.

RESULTS

There were 2063 single benzodiazepine overdose admissions: 131 alprazolam overdoses, 823 diazepam overdoses and 1109 other benzodiazepine overdoses. The median LOS for alprazolam overdoses was 19 h which was 1.27 (95% CI 1.04, 1.54) times longer compared with other benzodiazepines by multiple linear regression. For patients with alprazolam overdoses, 22% were admitted to ICU which was 2.06 (95% CI 1.27, 3.33) times more likely compared with other benzodiazepines after multivariate analysis adjusting for age, dose, gender, time to ingestion and co-ingested drugs. Flumazenil was administered to 14% of alprazolam patients and 16% were ventilated, which was significantly more than for other benzodiazepine overdoses (8% and 11%, respectively). Twelve percent of alprazolam overdoses had a GCS < 9 compared with 10% for other benzodiazepines. From benzodiazepine prescription data, total alprazolam prescriptions in Australia increased from 0.13 million in 1992 to 0.41 million in 2001. Eighty five percent of prescriptions were for panic disorder, anxiety, depression or mixed anxiety/depression.

CONCLUSIONS

Alprazolam was significantly more toxic than other benzodiazepines. The increased prescription of alprazolam to groups with an increased risk of deliberate self poisoning is concerning and needs review.

Fatal intentional poisoning cases admitted to the University Hospitals of Leuven, Belgium from 1993 to 1996

Between January 1993 and July 1996, a total of 2827 intentional cases of poisoning were registered in the University Hospitals of Leuven, Belgium. Ten of these cases were fatal. This study was set up to evaluate the substances involved, the circumstances, the features and the characteristics of the patients who died due to intentional poisoning. The male to female ratio of these fatal cases was 9 : 1. The median age was 43 years. Two groups of substances were revealed to be associated with fatal outcome. The first group consisted of chemicals (seven lethal cases): cholinesterase inhibitors ( =3), methanol ( =2) and paraquat ( =2). The second group consisted of benzodiazepines (three lethal cases). In the cases of poisoning with chemicals, death was directly related to product toxicity and the severity of the poisoning, whilst with benzodiazepines, which are considered to be relatively safe drugs even when taken in overdose, there was a clear relationship between a fatal outcome and a delay between ingestion and medical support. Product toxicity, complications and a delay in medical support may be considered as predictors for the effectiveness and efficacy of treatment and may influence which medical treatments need to be administered.