Prescribing trends in cognition enhancing drugs in Australia.

BACKGROUND

This study sought to examine the trends in the prescribing of subsidized and unsubsidized cognition enhancing drugs (CEDs) in Australia over five years from 2002 to 2007. Subsidized cholinesterase inhibitor medication could be prescribed to people with mild to moderate Alzheimer's disease (AD) once a specialist physician had confirmed this diagnosis. Memantine was available for use in moderately severe AD but not subsidized.

METHODS

We analyzed the Medicare Australia and Drug Utilisation Sub-Committee databases for CED prescription data, 2002-2007, by gender, age and prescriber class. Aggregated prescription data for each medication were converted to defined daily doses (DDD) per 1000 persons per day using national census data.

RESULTS

There were 1,583,667 CED prescriptions dispensed during the study period. CED use increased 58% from 0.91 to 1.56 DDD/1000 persons/day between 2002 and 2007. Peak use was in those aged 85-89 years. Age-adjusted utilization was slightly higher in females than males. Donepezil was the most widely used CED (66%), followed by galantamine (27%) then memantine (4%). General practitioners prescribed the majority of CEDs. Geriatricians exhibited a greater preference for galantamine than other prescribers. CED dispensing peaked towards the end of each calendar year, reflecting stockpiling by patients under the influence of a federal safety net subsidy.

CONCLUSIONS

Despite subsidized access to CEDs in Australia, only a minority of people with AD was prescribed these drugs during the period of the study. It is likely that the combination of complex prescribing rules and negative perceptions about efficacy or cost-effectiveness might have contributed to these findings.