Naftopidil for the treatment of urinary symptoms in patients with benign prostatic hyperplasia

Abstract

Naftopidil, approved only in Japan, is an α1-adrenergic receptor antagonist (α1-blocker) used to treat lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). Different from tamsulosin hydrochloride and silodosin, in that it has higher and extremely higher affinity respectively, for the α1A-adrenergic receptor subtype than for the α1D type, naftopidil has distinct characteristics because it has a three times greater affinity for the α1D-adrenergic receptor subtype than for the α1A subtype. Although well-designed large-scale randomized controlled studies are lacking and the optimal dosage of naftopidil is not always completely determined, previous reports from Japan have shown that naftopidil has superior efficacy to a placebo and comparable efficacy to other α1-blockers such as tamsulosin. On the other hand, the incidences of ejaculatory disorders and intraoperative floppy iris syndrome induced by naftopidil may be lower than for tamsulosin and silodosin having high affinity for the α1A-adrenergic receptor subtype. However, it remains unknown if the efficacy and safety of naftopidil in Japanese is applicable to white, black and Hispanic men having LUTS/BPH in western countries.

Enantiospecific determination of naftopidil by RRLC–MS/MS reveals stereoselective pharmacokinetics and tissue distributions in rats

“…Naftopidil (NAF; R,S-1-(4-(2-methoxyphenyl)-1-piperazinyl)-3-(1-naphthyloxy)-2-propanol) is a specific subtype of selective ␣ 1 -adrenoceptor blocker frequently used for LUTS/BPH treatment [4,5]. Previous studies have shown that NAF exhibits superior efficacy compared with other ␣ 1 -adrenoceptor blockers, such as tamsulosin, and incidence rates of ejaculatory disorders and intraoperative floppy iris syndrome induced by NAF are lower than those induced by tamsulosin and silodosin [5,6].…”

α1‐blocker tamsulosin as initial treatment for patients with benign prostatic hyperplasia: 5‐year outcome analysis of a prospective multicenter study

“…8 However, the study was carried out as a retrospective study using naftopidil, which has a threefold higher affinity for a1D than for the a1A subtype and is only available in Japan. 12 Thus, in the present study, we prospectively evaluated what percentage of patients dropped out during a 5-year follow-up period after administration of tamsulosin, which has a threefold higher affinity for a1A than for the a1D subtype and is universally available, and the reasons why they terminated medication, including patients who were lost to follow up. In addition, static and dynamic variables to predict treatment failure and conversion to surgery were determined, as well as the long-term efficacy and safety of tamsulosin.…”

A Randomized Study Comparing Once-Daily and Thrice-Daily Naftopidil 75 mg/Day for Lower Urinary Tract Symptoms of Benign Prostatic Hyperplasia

“…Naftopidil was approved at an OD dosage [2]. Generally, OD dosing contributes to improved drug compliance.…”

“…Therefore, it shows fewer adverse effects related to blood pressure [1]. The effects of naftopidil are dose-dependent, and the optimal dosage for the treatment of LUTS associated with BPH (LUTS/BPH) in Japan is recommended to be from 25 mg/day to 75 mg/day [2].…”