The risk of polypharmacy, comorbidities and drug–drug interactions in women of childbearing age with multiple sclerosis

BACKGROUND AND AIMS: Multiple sclerosis (MS) is the most common neuroimmunological disease of the central nervous system in young adults. Despite recommended contraception, unplanned pregnancies can occur in women of childbearing age with MS. MS- and comorbidities-related multimedication in these patients represents a potential risk. We aimed to raise awareness regarding the frequency of polypharmacy and drug–drug interactions (DDIs) in female MS patients of childbearing age. METHODS: Sociodemographic, clinical and pharmaceutical data were collected through patient records, clinical investigations and structured patient interviews of 131 women with MS. The clinical decision support software MediQ was used to identify potential DDIs. A medication and DDI profile of the study population was created by statistical analysis of the recorded data. RESULTS: Of the 131 female MS patients, 41.2% were affected by polypharmacy (concurrent use of ⩾5 drugs). Polypharmacy was associated with higher age, higher degree of disability, chronic progressive MS disease course and comorbidities. With an average intake of 4.2 drugs per patient, a total of 1033 potential DDIs were identified. Clinically relevant DDIs were significantly more frequent in patients with polypharmacy than in patients without polypharmacy (31.5% versus 5.2%; Fisher’s exact test: p < 0.001). CONCLUSION: For the first time, a comprehensive range of potential DDIs in women of childbearing age with MS is presented. Polypharmacy is associated with the occurrence of clinically relevant DDIs. This shows the need for effective and regular screening for such interactions in order to prevent avoidable adverse effects.