Solifenacin plus tamsulosin combination treatment in men with lower urinary tract symptoms and bladder outlet obstruction: A randomized controlled trial

Background: Alpha blockers are prescribed to manage lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). Antimuscarinics are prescribed to treat overactive bladder (OAB). Objective: To investigate the safety of a combination of solifenacin (SOLI) and tamsulosin oral controlled absorption system (TOCAS) in men with LUTS and bladder outlet obstruction (BOO). Design, setting, and participants: Randomized, double-blind, parallel-group, placebo-controlled study in men aged >45 yr with LUTS and BOO for ≥3 mo, total International Prostate Symptom Score (IPSS) ≥8, BOO index ≥20, maximum urinary flow rate (Q_max) ≤12 ml/s, and voided volume ≥120 ml. Interventions: Once-daily coadministration of TOCAS 0.4 mg plus SOLI 6 mg, TOCAS 0.4 mg plus SOLI 9 mg, or placebo for 12 wk. Outcome measurements and statistical analysis: Primary (safety) measurements: Q_max and detrusor pressure at Q_max (P_detQ _max). Other safety assessments included postvoid residual (PVR) volume. Secondary end points included bladder contractile index (BCI) score and percent bladder voiding efficiency (BVE). An analysis of covariance model compared each TOCAS plus SOLI combination with placebo. Results and limitations: Both active treatment groups were noninferior to placebo at end of treatment (EOT) for P_detQ_max and Q_max. Mean change from baseline PVR was significantly higher at all time points for TOCAS 0.4 mg plus SOLI 6 mg, and at weeks 2, 12, and EOT for TOCAS 0.4 mg plus SOLI 9 mg versus placebo. Both treatment groups were similar to placebo for BCI and BVE. Urinary retention was seen in only one patient receiving TOCAS 0.4 mg plus SOLI 6 mg. Limitations of the study were that prostate size and prostate-specific antigen level were not measured. Conclusions: TOCAS 0.4 mg plus SOLI 6 mg or 9 mg was noninferior to placebo at EOT for P_detQ_max and Q _max in men with LUTS and BOO, and there was no clinical or statistical evidence of increased risk of urinary retention.