Twenty-year trends in benzodiazepine dispensing in the Australian population
Article first published online: 23 JAN 2014
© 2013 The Authors; Internal Medicine Journal © 2013 Royal Australasian College of Physicians
Internal Medicine Journal
Volume 44, Issue 1, pages 57–64, January 2014
How to Cite
Islam, M. M., Conigrave, K. M., Day, C. A., Nguyen, Y. and Haber, P. S. (2014), Twenty-year trends in benzodiazepine dispensing in the Australian population. Internal Medicine Journal, 44: 57–64. doi: 10.1111/imj.12315
Conflict of interest: None.
- Issue published online: 23 JAN 2014
- Article first published online: 23 JAN 2014
- Accepted manuscript online: 25 OCT 2013 06:06AM EST
- Manuscript Accepted: 3 OCT 2013
- Manuscript Received: 28 JUL 2013
- anxiolytic drug;
- defined daily dose;
- Ashton equivalent dose
Considerable concern has been expressed about overprescribing of benzodiazepines and related harms. Past analyses have relied on World Health Organization-defined daily doses (DDD) which are sometimes out of keeping with clinical usage. This study examines 20-year (1992–2011) trends of benzodiazepine dispensing in Australia using both DDD and Ashton equivalent dose.
Data from the Drug Utilisation Sub-Committee and the Pharmaceutical Benefits Scheme (PBS) website were analysed. Trends in number of prescriptions, DDD/1000 people/day and DDD/prescription were examined over time, and between states/territories.
In the 20-year period, 174 080 904 scripts were recorded, with temazepam the most dispensed benzodiazepine (35% of scripts), followed by diazepam (23%). Overall recorded utilisation fell from 27.7 DDD/1000 people/day in 1992 to 20.8 in 2011 (24.9% decrease). There were striking changes in use of individual benzodiazepines over time, with reductions in oxazepam and flunitrazepam and dramatic increases in alprazolam. Since 1998, there has been a steady increase, albeit modest, in per script DDD. The DDD/1000 people/day for items dispensed through PBS/Repatriaton-PBS was highest in Tasmania and lowest in Northern Territory.
Despite a modest overall decline in the amount of benzodiazepine dispensed, the level of use is still likely to reflect relative over-prescribing given the paucity of accepted indications for long-term use. Since 1998, there was a polynomial increase in quantity dispensed per script. The WHO-defined DDD for clonazepam seems inappropriate and could impede monitoring of its abuse. Other problems include lack of national data for medications not subsidised on PBS/Repatriation PBS. A broad policy approach is required, not one which targets only one particular benzodiazepine.