Cutoff level of prostate volume to predict the efficacy of α1-D/A adrenoceptor antagonist, naftopidil.

INTRODUCTION: In lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH) patients, prostate volume (PV) at baseline affects the improvement of International Prostate Symptom Score voiding symptoms (IPSS-VS) by naftopidil (NAF), but not total IPSS (IPSS-TS). To predict the efficacy of NAF, the PV cutoff point was examined using IPSS-VS. MATERIALS AND METHODS: Seventy-seven patients with LUTS/BPH were administrated with NAF 50 mg/day for 4 weeks. Age, PV, IPSS, IPSS quality-of-life (IPSS-QoL), and maximum flow rate (MFR) were evaluated at baseline, and IPSS, IPSS-QoL, and MFR were evaluated after the treatment (at 4 weeks). Responders and nonresponders were divided by IPSS-VS at 4 weeks, and the PV cutoff point was calculated. RESULTS: At baseline, the mean age and PV were 70.7 ± 8.2 years (range, 54-88 years) and 43.3 ± 24.5 mL (range, 20.6-141.7 mL), respectively. After 4 weeks, area under the receiver operating characteristic curve was largest in the patients with <4 points of IPSS-VS. The best standard value to evaluate the efficacy IPSS-VS at 4 weeks was 4 points for the NAF treatment, and the best PV cutoff point was 37.3 mL (sensitivity 60.5%, specificity 71.9%). CONCLUSIONS: PV at baseline was one of the predictive factors which affected the efficacy of NAF for IPSS-VS, and LUTS/BPH patients who had PV more than 37.3 mL indicated poor improvement of IPSS-VS, even if IPSS-TS was improved.

The predictive factors of α1-D/A adrenoceptor antagonist, naftopidil, dose increase therapy for male lower urinary tract symptoms caused by benign prostatic hyperplasia: INFORM study.

INTRODUCTION: We evaluated the predictive factors which affect the efficacy of naftopidil 50 mg/day therapy and dose increase therapy to administration of 75 mg/day after an initial dose of 50 mg/day. MATERIALS AND METHODS: A total of 92 patients with male lower urinary tract symptoms/benign prostatic hyperplasia were administrated naftopidil 50 mg/day for 4 weeks (50 mg therapy). At week 4, the patients were divided into an effective and an ineffective group (Group E and Group I, respectively). For further 4 weeks, the dosage of naftopidil was increased to 75 mg/day in all patients. At week 8, the patients of Group E and Group I were divided into an effective and an ineffective group (Group EE, Group EI, Group IE, and Group II, respectively). RESULTS: Postvoid residual (PVR) urine volume at baseline was a predictive factor for efficacy of 50 mg therapy. In Group E, change in International Prostate Symptom Score storage symptoms subscore from baseline to week 4 was a predictive factor for efficacy of this dose increase therapy. In Group I, change in maximum flow rate from baseline to week 4 was a predictive factor for efficacy of this dose increase therapy. CONCLUSIONS: The short term of naftopidil 50 mg therapy was ineffective for the patients who had large PVR. The predictive factor of this dose increase therapy might be a dynamic variable in 50 mg/day of dose period, but not a baseline variable at the time of 75 mg/day dosage starts.

Does prostate volume affect the efficacy of α1D/A: Adrenoceptor antagonist naftopidil?

INTRODUCTION: There have been reports that one of the factors affecting the efficacy of α1-adrenoceptor antagonists (α1-blocker; α1-B) was prostate volume (PV). However, there are few reports of short-term prospective trials comparing the efficacy of α1-B by PV. We examined the influence of PV on the short-term efficacy of naftopidil dose increase therapy to administration of 75 mg/day after an initial dose of 50 mg/day. MATERIALS AND METHODS: A total of 85 patients with lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH) received 50 mg/day of naftopidil for 4 weeks. After 4 weeks, the dosage of naftopidil was increased to 75 mg/day for a further 4 weeks. We divided the patients into two groups of PV ≥40 mL at baseline (Group L) and PV <40 mL at baseline (Group S). RESULTS: International Prostate Symptom Score (IPSS), IPSS storage symptoms, and IPSS quality-of-life score were significantly improved at 4 and 8 weeks compared with baseline in both Groups. IPSS voiding symptoms (IPSS-VS) were significantly improved at 4 and 8 weeks compared with baseline in Group S. IPSS and IPSS-VS were significantly improved at 8 weeks compared with 4 weeks only in Group L. IPSS-VS and intermittency at 4 weeks were significantly decreased in Group S compared with Group L. Maximum flow rate was significantly improved at 8 weeks compared with baseline in Group L. CONCLUSIONS: PV is a predictive factor affecting the efficacy of naftopidil 50 mg/day for IPSS-VS, and the dose increase to 75 mg/day effective for IPSS-VS. A total of 50 mg/day of naftopidil is the maintenance dose for LUTS/BPH patients with a small PV, and 75 mg/day of dose increase therapy should be chosen for patients with a large PV.