Purpose: While some people remain fit and active as they grow older, others experience complex problems: disease, dependency and disability. Frailty is a term used to describe this latter group, capturing differences in health status among older people. Many frail older people have multiple chronic co-morbidities and functional impairments and, according to guidelines for the management of individual conditions, should be prescribed long lists of medications. However, older people (particularly those who are frail) are often excluded from drug trials, and treatment decisions are therefore based on evidence extrapolated from more robust patient groups with fewer physiological deficits. The risk of adverse drug reactions (ADRs) increases with increasing patient frailty, and polypharmacy has negative consequences above and beyond the risks of individual drugs. Increasing numbers of medications are associated with a higher likelihood of non-adherence and a significantly greater risk of ADRs. Older people taking five or more medications are at higher risk of delirium and falls, independent of medication indications.
Methods: This is a short review of the different approaches to defining and measuring frailty. We summarise the factors contributing to ADRs in frail older people and describe the pharmacokinetic and pharmacodynamics changes associated with ageing and frailty. By considering goals of care for frail older people, we explore how the appropriateness of medication prescribing for older people could be improved.
Conclusion: Since all physicians are likely to provide care for this group of vulnerable patients, understanding the concept of frailty may help to optimise medication prescribing for older people. The incorporation of frailty measures into future clinical studies of drug effects and pharmacokinetics is important if we are to improve medication use and guide drug doses for fit and frail older people.