Comparison of the efficacy and tolerability of solifenacin succinate with or without previous use of trospium chloride

Overactive bladder syndrome (OBS) is described as urinary urgency with or without incontinence, usually with increased daytime frequency and nocturia in the absence of another identifiable pathological process. Nowadays and despite other alternative therapies, the mainstay of OBS is still the pharmacological approach, mainly with anti-muscarinic drugs. To compare the efficacy of a 30-day solifenacin succinate (5 mg OD) treatment with or without previous medication with trospium chloride, a prostective open, two-arm, parallel group study was conducted for 5 weeks in 40 patients with OBS. The primary endpoint was patient self-assessment of improvement after 30 days of medication. Secondary endpoints included the reduction of the daily number of voids and urgency or involuntary leakage episodes. Adverse reactions and therapeutic stoppage were also evaluated. To be included in the trospium chloride treatment group, patients were required to have been treated with such drug for 1 to 6 months before the present study. Evaluation and efficacy assessment were accomplished using a 3-day bladder diary and an urgency severity scale (USS). Safety assessment was done by recording all the patients’ complaints after starting medication. A total of 40 patients were enrolled for this study, 19 without previous medication and 21 who had already tried trospium chloride. Two patients from the non-previous medication group were excluded. Globally, there was a statistically significant reduction for the USS (2.73→1.73), the daily number of voids (9.5→7.0), of urgency episodes (9.1→4.0) and of involuntary leakage episodes (3.6→1.0) over the 24 h. Six patients had no improvement, four from the previous trospium chloride group and two from the non-previous medication group. Three patients reported side effects, two cases of dry mouth and one case of constipation. One patient dropped out of the treatment due to an unspecified intolerance. Solifenacin succinate 5 mg seems to be effective concerning patients’ self-assessment of improvement and decrease in the mean number of daily voids, urgency episodes and incontinence episodes. This was reported both in patients who have already been medicated with trospium chloride and those who have never taken any kind of medication. Regarding side effects, solifenacin is quite well-tolerated in both groups.