Comparison of 25 and 75 mg/day naftopidil for lower urinary tract symptoms associated with benign prostatic hyperplasia: A prospective, randomized controlled study

Background: The present study investigated the efficacy, safety, and utility of starting an α _1d-selective antagonist, naftopidil, at 75 or 25 mg/day in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). Methods: In this prospective comparative study, the subjects comprised 153 patients with LUTS associated with BPH. Patients were randomized to receive either 25 mg/day (Group LD) or 75 mg/day (Group HD) of naftopidil for 4 weeks. The lower urinary tract disease symptom score (LUTDSS), the International Prostate Symptom Score (IPSS), the Quality of life assessment index, the maximum flow rate (Q _max), and the residual urine volume were compared between the groups. Results: In both groups, the LUTDSS and the IPSS were significantly improved at the endpoint and no significant intergroup differences were identified. However, the improvement in the Q _max was significantly better for Group HD than for Group LD. The overall efficacy did not differ significantly between the groups. The degree of improvement in voiding symptoms and LUTDSS among patients with moderate symptoms was significantly greater for Group HD than for Group LD. The frequency of adverse reactions did not differ significantly between the groups. Conclusions: Starting administration at 75 mg/day rather than 25mg/day is helpful for LUTS associated with BPH for patients with moderate symptoms, particularly in improving voiding symptoms. The 75 mg/day administration was considered to be a recommendable therapeutic dose in some patients.