Dementia affects a growing number of Australians, with estimates placing the number living with the condition at around 425,000 in recent years. Projections suggest this figure will more than double by mid-century as the population ages.
While medications such as cholinesterase inhibitors (donepezil, galantamine, rivastigmine) and memantine play a valuable role in managing symptoms for many people, particularly those with Alzheimer’s disease, their use often occurs within a broader context of multiple medications. This polypharmacy, especially when it includes potentially inappropriate medicines (PIMs), raises important safety considerations.
Recent Australian research highlights the scale of the issue. In residential aged care facilities, where a significant proportion of people with dementia reside, exposure to polypharmacy, defined as five or more regular medications, though often higher thresholds such as nine or more are used, and PIMs is widespread.
One 2024 study analysing data from over 16,000 residents who received a residential medication management review (RMMR) in 2019 found that 74% of those with dementia experienced polypharmacy compared with 70% without dementia. It also found that 83% were exposed to at least one PIM versus 73% of residents without dementia. These differences were statistically significant, underscoring how dementia can amplify risks associated with complex medication regimens.
Other studies reinforce this pattern. In a repeated cross-sectional analysis of older people in residential aged care, 92% were exposed to polypharmacy, defined as five or more medicines, with an average of more than 10 regular medications taken daily, and 85% had highly complex regimens.
Longitudinal cohort research tracking residents over three years from admission shows persistently high rates of polypharmacy, often around or above 70 to 80%, depending on definitions and time points. In community settings, similar concerns emerge, with one cross-sectional study reporting polypharmacy in 65% of people with dementia and PIM use in 76%.
High-risk prescribing encompasses not just the sheer number of medicines but also the use of drugs flagged as potentially inappropriate under tools such as the Beers Criteria, updated in 2019, or Australian-specific PIM lists. Common culprits include anticholinergics, such as certain bladder or allergy medications, sedatives, proton pump inhibitors, and benzodiazepines.
These medicines can worsen confusion, increase the risk of falls, or contribute to delirium, particularly in frail older adults living with dementia.
Cholinesterase inhibitors themselves, while generally having low to moderate anticholinergic activity, can add to the overall anticholinergic burden when combined with other drugs. Australian and international evidence links higher anticholinergic exposure to risks such as cognitive worsening, falls, and syncope, although findings vary.
Some reviews report no strong association with residential care admission or physical decline, while others highlight potential interactions that may exacerbate symptoms. In practice, concurrent prescribing of anticholinergics alongside cholinesterase inhibitors occurs in a notable minority of cases and is sometimes linked to multiple prescribers and poor coordination of care.
These prescribing patterns are particularly concerning in aged care settings, where residents often have advanced dementia, multimorbidity, sensory impairments, and limited mobility. Polypharmacy in this context heightens vulnerability to adverse drug events, hospitalisations, and reduced quality of life. Behavioural and psychological symptoms of dementia may prompt the addition of psychotropic medications, despite guidelines prioritising non-pharmacological approaches as first-line treatment.
Post-Royal Commission reforms, including updated psychotropic prescribing guidelines released in 2023 and strengthened deprescribing recommendations, aimed to curb inappropriate use, though implementation remains uneven.
That said, dementia-specific medications can offer real benefits for appropriate candidates. Cholinesterase inhibitors may provide modest improvements in cognition, function, and sometimes behaviour in mild to moderate stages of the disease, while memantine can help stabilise symptoms in moderate to severe dementia.
Pharmaceutical Benefits Scheme data from 2023–24 shows nearly 737,000 prescriptions dispensed to approximately 77,500 people aged 30 and over, with donepezil accounting for roughly two-thirds of all scripts. This reflects its established role and perceived clinical value for many patients.
The key lies in careful, individualised management. Regular medication reviews involving GPs, pharmacists, specialists, and families are essential to determine when benefits continue to outweigh risks and when deprescribing may be appropriate.
Tools such as RMMRs and emerging pharmacist-led safety rounds can support this process. Shared decision-making helps families understand both the potential benefits, such as preserved independence or meaningful time with loved ones, and the limitations, including side effects and interactions within complex medication regimens.
Addressing high-risk prescribing requires sustained effort to promote appropriate medicine use, improve continuity of care, and prioritise non-drug strategies wherever possible. In Australia’s evolving aged care landscape, striking this balance is critical to maximising safety and quality of life for people living with dementia.
