A prospective, observational study to assess the association between dry mouth and solifenacin treatment in patients with overactive bladder syndrome

Purpose: Dry mouth is among the most common side effects of antimuscarinic therapy. This study evaluated the drug-related change in dry mouth after the solifenacin treatment and the impact of dry mouth on the drug efficacy against overactive bladder syndrome (OAB).

Materials and methods: OAB patients (n = 331) were enrolled in a prospective, multicenter, 8-week observational study of solifenacin treatment. Participants were >20 years of age and presented with OAB symptoms for ≥3 months, a total overactive bladder symptom score (OABSS) of ≥3, and an urgency score of ≥2. Primary endpoints were changes in dry mouth according to baseline dry mouth status using Xerostomia Inventory (XI) and the effect of dry mouth to the drug efficacy according to improvements in the OABSS.

Results and conclusions: Three hundred and thirty-three patients were initially screened for the study, with 331 actually enrolled. One hundred and ninety-four patients completed the study. Mean total XI scores increased by 2.8 points in the entire patient population, with larger increases for patients stratified into the non-dry mouth group (NDG) versus the dry mouth group (DG) (4.0 vs. 1.9, p = 0.015) at study baseline. Mean total OABSSs decreased by 3.2 points, with no significant differences between the NDG and the DG (−3.4 vs. −3.0 points, p = 0.578). The dry mouth aggravated in 71 patients (29.2 %) (NDG 30.1 % and DG 27.1 %), but only 10/331 individuals (3.0 %) stopped medication due to xerostomia. Dry mouth progressed in approximately 30 % of the OAB patients, regardless of its presence before solifenacin treatment. However, OAB symptoms were well relieved by solifenacin, and the adverse influence of dry mouth on drug persistence was low.