Combination treatment with propiverine hydrochloride plus doxazosin controlled release gastrointestinal therapeutic system formulation for overactive bladder and coexisting benign prostatic obstruction: A prospective, randomized, controlled multicenter study

Purpose: We evaluated the efficacy and safety of a therapeutic modality involving propiverine combined with doxazosin in patients with overactive bladder (OAB) and benign prostatic obstruction. Materials and Methods: Men 50 years or older with OAB symptoms and urodynamically proven bladder outlet obstruction (Abrams-Griffith score greater than 20) were randomized (1:2) into 2 groups, namely group 1-doxazosin controlled release gastrointestinal therapeutic system formulation (4 mg once daily) only and group 2-propiverine hydrochloride (20 mg once daily) plus doxazosin controlled release gastrointestinal therapeutic system formulation for an 8-week treatment regimen. Results: A total of 211 men, including 69 in group 1 and 142 in group 2, were treated and 198 (93.8%) completed the 8 weeks of treatment. Significant improvements were noted in each group after treatment in urinary frequency, maximum flow rate, average micturition volume and International Prostate Symptom Score. Compared with group 1 improvement rates with regard to urinary frequency (23.5% vs 14.3%, p = 0.004), average micturition volume (32.3% vs 19.2%, p = 0.004), and storage (41.3% vs 32.6%, p = 0.029) and urgency (p = 0.019) International Prostate Symptom Score symptoms were more significant in group 2. Post-void residual urine was found to be significantly increased only in group 2 but this was not accompanied by urinary retention. Patient satisfaction rates were found to be significantly higher in group 2 than in group 1 (p = 0.002). Overall adverse event rates were higher in group 2 (p = 0.002), although discontinuation rates and discontinuation rates due to adverse events were not different between the 2 groups. Conclusions: This study reveals that combination therapy consisting of α1-adrenoceptor antagonists with antimuscarinics represents an effective and relatively safe treatment modality in select patients with OAB coexisting with benign prostatic obstruction.