Urodynamic effects of silodosin, a new α1A‐adrenoceptor selective antagonist, for the treatment of benign prostatic hyperplasia

Abstract

To investigate urodynamically the effects of silodosin, a new alpha(1A)-adrenoceptor-selective antagonist, in the treatment of benign prostatic hyperplasia (BPH). Thirty six male patients with BPH (69.9 +/- 7.3 years), who were referred as candidates for surgery, were treated with silodosin (4 mg twice daily). The total International Prostate Symptom Score (IPSS) was 20.7 +/- 7.4, maximum flow rate (Q(max)) was 6.7 +/- 3.0 ml/sec, and prostate volume was 45.6 +/- 24.5 ml. Total IPSS, storage and voiding symptom subscores and QOL score decreased significantly, and Q(max) increased significantly after 1-12 months of therapy (all P < 0.05). In urodynamic study (n = 29), maximum cystometric capacity increased significantly (P = 0.0027), and detrusor overactivity disappeared in 8 of 20 patients (40%) and improved (bladder capacity increased more than 50%) in 7 (35%) after the therapy. In pressure/flow studies (n = 27), the obstruction grade was improved in 15 patients (56%). Detrusor opening pressure, detrusor pressure at Q(max), bladder outlet obstruction index, and Schäfer's obstruction class decreased significantly after therapy (all P < 0.01). After 12 months, 16 patients (44%) are still on silodosin for 23.3 +/- 7.0 (range 12-36) months, and the improvements in IPSS and Q(max) were stable. Twenty patients withdrew because of insufficient effectiveness in 13 patients (12 patients underwent surgery), side effects in 3, and unknown reasons in 4. Silodosin appears to improve detrusor overactivity and obstruction grade in patients with BPH. With silodosin treatment, LUTS could be managed effectively for more than a year in at least 44% of the patients.