Benzodiazepine utilisation in Australia: report from a new pharmacoepidemiological database.

This study surveys the total community prescription use of benzodiazepine agents in Australia for the years 1990 and 1991. Also included is information on the utilisation of these agents on the Pharmaceutical Benefits and Repatriation Pharmaceutical Benefits Schemes (PBS/RPBS) over the period 1987 to 1991. The Australian data are from the Drug Utilization Subcommittee (DUSC) database, which is derived from two sources: the PBS/RPBS (subsidized prescriptions), and a national sample of Pharmacy Guild of Australia pharmacies (private and under-copayment general prescriptions). The data are converted to defined daily doses per 1000 inhabitants per day (DDD/1000/day) in accordance with the unit of measurement for drug utilisation studies approved by the World Health Organization. Benzodiazepine utilisation was 33.96 DDD/1000/day for 1990 and 29.31 DDD/1000/day for 1991. The four drugs listed on the Pharmaceutical Benefits Scheme, namely diazepam, oxazepam, nitrazepam and temazepam, constituted 82 per cent of the Australian market. The availability of government subsidy appears to influence benzodiazepine- prescribing behaviour. Benzodiazepine utilisation has been falling in recent years. The fall may be related to the impact of new guidelines and community awareness campaigns. There are major differences in the composition of the market between Australia and the Nordic countries.