Improvement of Overactive Bladder Symptoms and Bladder Ischemia with Dutasteride in Patients with Benign Prostatic Enlargement.

OBJECTIVES To evaluate the correlation of clinical and urodynamic parameters with bladder vascular resistance before and after dutasteride treatment in patients with lower urinary tract symptoms associated with benign prostatic enlargement. METHODS A prospective study was conducted in 30 consecutive patients with benign prostatic enlargement who had not been satisfied with alpha-adrenergic antagonist monotherapy. Before and 24 weeks after dutasteride add-on treatment, we assessed International Prostate Symptom Score (IPSS), prostate volume (PV), urodynamic study and contrast-enhanced color Doppler ultrasonography to measure bladder vascular resistive index (RI). RESULTS Twenty-four weeks after dutasteride, PV significantly decreased from 68 ± 29 to 48 ± 28 mL (P < 0.001), and there was significant improvement of IPSS (from 18.8 ± 7.7 to 13.4 ± 7.2, P < 0.001). Urgency score of IPSS was also significantly improved from 2.3 ± 1.9 to 1.4 ± 1.4 (P < 0.01) after dutasteride. On pressure-flow study, bladder outlet obstruction index (BOOI) (from 58 ± 36 to 38 ± 27, P < 0.001) and detrusor pressure at Qmax (PdetQmax) (from 73 ± 34 to 54 ± 25 cmH2 O, P < 0.001) were significantly improved. RI significantly decreased after dutasteride (from 0.548 ± 0.069 to 0.486 ± 0.064, P < 0.001). In 20 patients with persistent urgency after dutasteride, RI was less improved than in another 10 patients without urgency (change of RI 0.045 ± 0.091 vs. 0.096 ± 0.042, P < 0.05). Post-treatment BOOI and PdetQmax in patients with persistent urgency was significantly higher than in those without urgency after dutasteride (BOOI: 46 ± 28 vs. 24 ± 20, P < 0.05, PdetQmax: 62 ± 26 vs. 40 ± 17 cmH2 O, P < 0.01). CONCLUSIONS Reduction of obstruction and improvement of bladder ischemia might play an important role in a beneficial impact of dutasteride on overactive bladder symptoms.