Polypharmacy

Polypharmacy is conventionally defined as the concurrent use of five or more medications by one patient, though thresholds vary by definition (some use ≥4, hyperpolypharmacy typically ≥10); it must be distinguished from appropriate polypharmacy, in which multiple drugs are each evidence-based for the individual's conditions. Prevalence increases sharply with age and multimorbidity — over 40% of adults aged 65 and older in many high-income countries take five or more drugs. The clinical risks include drug-drug interactions, additive adverse effects, prescribing cascades (where a drug side effect is treated with another drug), impaired adherence, falls, cognitive impairment and hospitalisation. Deprescribing — the structured reduction of medications that lack net benefit — is an emerging discipline in geriatric and longevity medicine, supported by a growing evidence base for specific drug classes including proton pump inhibitors, benzodiazepines and anticholinergics in older adults.