Polypharmacy, Potential Drug-Drug Interactions and Medication Non-Adherence in Patients with Multiple Sclerosis: A Longitudinal Study.

In contrast, monthly medication non-adherence remained stable (25.7% to 27.3%, p = 0.855).

Major interactions accounted for 7.1% of all identified DDIs.

Older age, disability pension status, higher disability levels, coexisting medical conditions, and lower educational attainment were associated with polypharmacy and the presence of DDIs, whereas non-adherence was linked to prior non-adherent behavior and inpatient care at baseline.