Solifenacin improves urinary symptoms but worsens constipation in MS patients with OAB

In the treatment of multiple sclerosis (MS) patients with overactive bladder (OAB) symptoms, mirabegron and solifenacin yield similar response rates, with the latter producing a greater decrease in urinary symptom severity but exerting a less favourable effect on constipation, a study has found.

The study included 61 MS patients who had not received treatment for their OAB symptoms. Patients enrolled in years 1–2 were administered mirabegron, whereas those enrolled in years 3–4 were prescribed solifenacin. All of them completed the OAB Questionnaire Short Form (OAB-q SF) and Patient Assessment of Constipation Symptoms (PAC-SYM) at baseline and 6-week follow-up.

A similar number of patients in the mirabegron and the solifenacin groups achieved the primary outcome of minimal clinically important difference (MCID) in OAB-q SF symptom severity (70 percent vs 69 percent, respectively).

However, patients on solifenacin showed a significantly greater improvement in the OAB-q SF score at the end of the study (−37.87 vs −20.43; p=0.02).

Meanwhile, constipation improved in the mirabegron group and worsened in the solifenacin group (change in PAC-SYM, −0.38 vs 0.22; p=0.02), and 30 percent of patients who were prescribed the latter experienced worsening above the MCID threshold.

Although there is short-term evidence of a more favourable improvement in urinary symptom severity with solifenacin, this potential benefit must be weighed against the observed risk of worsening constipation, according to researchers. Additional investigation is required to confirm these findings.