Involvement of magnitude of ambient temperature change in nonspecific effect in perceived placebo effect on lower urinary tract symptoms: study on switching of naftopidil in patients with benign prostatic hyperplasia.

Purpose: To determine if switching from one brand of the α1-adrenoceptor antagonist naftopidil (Avishot™) to another brand (Flivas™) under the same conditions causes the same changes in lower urinary tract symptoms (LUTS) and quality of life (QOL) as the perceived placebo effect, and if ambient temperature as a nonspecific factor is related to those changes in benign prostatic hyperplasia (BPH) patients.

Patients And Methods: A retrospective study was carried out on 217 BPH patients who had received Avishot™ for more than 6 months and then were switched to Flivas™ at the same dose and timing. The two drugs contain the same principal ingredient and display the same pharmacokinetic properties.