title: Does prostate volume affect the efficacy of α1D/A: Adrenoceptor antagonist naftopidil?
abstract: BACKGROUND
  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.
  
  
  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.
authors.affiliation: Department of Urology, Hokkaido Social Welfare Association Hakodate Hospital, Hakodate, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Tanuma
authors.affiliation: Department of Urology, Hokkaido Prefectural Esashi Hospital, Esashi, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Urology, Hakodate National Hospital, Hakodate, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Takeyama
authors.affiliation: Okamoto Urology Clinic, Hokkaido, Japan.
authors.forename: Tomoshi
authors.initials: T
authors.lastname: Okamoto
keywords: Dose increase therapy; naftopidil; prostate volume
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