Polypharmacy in multiple sclerosis: relationship with fatigue, perceived cognition, and objective cognitive performance

Patients with multiple sclerosis (MS) commonly use a variety of medications to slow disease progression, alleviate symptoms, and treat comorbid conditions. Polypharmacy has been linked to adverse outcomes in other patient groups, but has not been studied extensively in MS. We investigated the impact of polypharmacy on fatigue, objective neuropsychological performance, and subjective cognitive impairment in a sample of patients with MS.

MS patients (n=85) completed a medication inventory, self-report questionnaires, and a battery of neurocognitive tests. MS patients with polypharmacy were compared to MS patients without polypharmacy, using multivariate analysis of covariance (MANCOVA).

After controlling for disease characteristics, MS patients with polypharmacy (n=28) exhibited prospective memory deficits and reported significantly more fatigue and subjective cognitive problems than MS patients without polypharmacy.

Clinicians and patients should carefully weigh the costs and benefits of prescribing multiple medications, as these may contribute to iatrogenic fatigue and cognitive problems in MS. Moreover, researchers should account for polypharmacy when conducting studies examining fatigue and cognition in MS.