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Early Efficacy of an α 1 Adrenoceptor Antagonist, Naftopidil, against Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Hyperplasia
Author(s) -
ISHIZUKA Osamu,
NISHIZAWA Osamu,
TAKEDA Masayuki,
NOMURA Teruhisa,
KAGAWA Susumu
Publication year - 2011
Publication title -
luts: lower urinary tract symptoms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.451
H-Index - 15
eISSN - 1757-5672
pISSN - 1757-5664
DOI - 10.1111/j.1757-5672.2010.00084.x
Subject(s) - hyperplasia , lower urinary tract symptoms , urology , antagonist , medicine , urinary system , prostate , receptor , cancer
Objectives: The present study investigated the early efficacy of naftopidil against lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). Methods: Subjects comprised patients with LUTS suggestive of BPH who were followed prospectively for 8 weeks. Inclusion criteria were: (i) international prostate symptom score (IPSS) ≥8; (ii) no previous treatment for BPH; and (iii) eligibility for naftopidil monotherapy. IPSS and quality of life index were evaluated, and uroflowmetry and residual urine volume were determined optionally. In the previous study, patients who demonstrated a decrease in total American Urological Association symptom score of 25% or more from baseline were considered responders. The ratio of onset of efficacy of naftopidil was calculated by the ratio of the number of responder in each group with the starting dose. Results: Naftopidil efficacy was analyzed for 243 patients. Significant improvement of IPSS was achieved within 1–3 days after medication. Starting dosage and average dosage were identified as factors associated with the period until onset of naftopidil efficacy. Onset of efficacy was significantly quicker with a starting dosage of 50 mg/day as compared with 25 mg/day ( P = 0.0047). However, ratios of onset of efficacy with starting dosages of 25, 50 and 75 mg/day were 77.9, 76.7 and 85.7%, respectively, showing no significant difference between groups ( P = 0.7463). Duration to onset of efficacy with naftopidil dosage ≥50 mg/day was 11.2 days, significantly early compared to dosage <50 mg/day. Incidence of adverse effect was 3.8%. Conclusion: Naftopidil showed early effects against LUTS suggestive of BPH within a few days.