Polypharmacy is an important aspect of medication management and particularly affects elderly and
chronically ill people. Patients with
dementia,
Parkinson's disease (PD), or
multiple sclerosis (MS) are at high risk of multi medication due to their complex symptomatology. Our aim was to provide an overview of different definitions of
polypharmacy and to present the current state of research on
polypharmacy in patients with
dementia, PD, or MS. The most common definition of
polypharmacy in the literature is the concomitant use of ≥5 medications (quantitative definition approach).
Polypharmacy rates of up to >50% have been reported for patients with
dementia, PD, or MS, although MS patients are on average significantly younger than those with
dementia or PD. The main predictor of
polypharmacy is the complex symptom profile of these
neurological disorders. Potentially inappropriate medication (PIM), drug-drug interactions, poor treatment adherence, severe disease course,
cognitive impairment, hospitalisation, poor quality of life,
frailty, and mortality have been associated with
polypharmacy in patients with
dementia, PD, or MS. For patients with
polypharmacy, either the avoidance of PIM (selective
deprescribing) or the substitution of PIM with more suitable drugs (appropriate
polypharmacy) is recommended to achieve a more effective therapeutic management.