Predictive factors for the effect of the α1‐D/A adrenoceptor antagonist naftopidil on subjective and objective criteria in patients with neurogenic lower urinary tract dysfunction
Authors: Takeda Masayuki , Homma Yukio , Araki Isao , Kakizaki Hidehiro , Yamanishi Tomonori , Yokota Takashi , Gotoh Momokazu , Igawa Yasuhiko , Seki Narihito , Takei Mineo , Yoshida Masaki , Sugaya Kimio , Nishizawa Osamu ,   The Japanese Naftopidil Neurogenic Lower Urinary Tract Dysfunction Study Group
Published: November 2010

Study Type – Therapy (RCT)  Level of Evidence 1b

What's known on the subject? and What does the study add?

α‐blockers may have little effect in the facilitation of storage and emptying in patients with neurogenic lower urinary tract dysfunction (NLUTD).

Naftopidil is a novel α‐blocker, which is selective for the α1‐D/A adrenoceptor. This study showed the first objective evidence for the effect of naftopidil in treatment of NLUTD patients by pressure‐flow study.

OBJECTIVES

• To assess the effect of α1‐D/A adrenoceptor antagonist naftopidil on patients with neurogenic lower urinary tract dysfunction (NLUTD) and voiding difficulty.

• To explore the effectiveness of naftopidil in these patients by using urodynamic variables, including pressure flow study (PFS), and to find good and simple parameters (International Prostate Symptom Score (IPSS), Post‐void residual urine (PVR), and uroflowmetry (UFM) parameters) as substitution of PFS for predicting the effect of naftopidil.

PATIENTS AND METHODS

• The main inclusion and exclusion criteria were, IPSS ≥8, voiding symptoms with IPSS ≥5, IPSS‐quality of life (QOL) ≥2, PVR ≥50 mL, and without prostatic enlargement ≥20 mL.

• After initial assessment, patients were stepwisely administered for 12 weeks with the following: placebo for 2 weeks, naftopidil 25 mg/day for 2 weeks, naftopidil 50 mg/day for 2 weeks, and naftopidil 75 mg/day for 6 weeks. At the end of both placebo and 6 weeks’ naftopidil 75 mg/day, their IPSS, UFM, PVR, and PFS were assessed.

• A total of 82 Japanese patients (men 40, women 42) with lower urinary tract symptoms complicated by NLUTD, with a mean age of 63.9 years, were included from private or institutional clinics.

• The lesions were spinal cord 42, and peripheral nervous system 40. The spinal cord lesions were all lumbar spine (injury or lumbar canal stenosis).

RESULTS

• In all patients, pressure at maximum urinary flow rate (PdetQmax) in PFS significantly decreased (P < 0.05), and maximum urinary flow rate in UFM significantly increased (P < 0.01). Analysis of data for men and for women also showed a significant decrease in PVR, %PVR, and total IPSS score.

• The degree of improvement of voided volume, PVR (%), and IPSS in patients with PVR <300 mL was significantly greater than those in patients with PVR ≥300 mL.

• The degree of improvement of PdetQmax in PFS, and IPSS in patients with bladder contractility was significantly greater than that in patients without bladder contractility.

CONCLUSIONS

• α1‐D/A adrenoceptor antagonist naftopidil has a significant effect on both symptoms and urodynamic variables of patients of both genders with NLUTD in Japan.

• PVR <300 mL and bladder contractility are predictive factors for the efficacy of naftopidil on patients with NLUTD.