Login to Access Video or Poster Abstract: MP09-07
Sources of Funding: none

Introduction

Tadalafil is a phosphodiesterase 5 inhibitor that affects cyclic guanosine monophosphate (cGMP). It is known to improve not only smooth muscle relaxation of the prostatic urethra and bladder, but also pelvic ischemia. In the daily clinic, tadalafil is usually prescribed for patients with lower urinary tract symptoms (LUTS), but not all patients respond to tadalafil treatment. The purpose of this study was to identify those who would be good candidates for tadalafil. This evaluation used penile blood pressure (PBP) as a feasible and reproducible method related to pelvic blood perfusion.

Methods

A prospective study was performed in our hospital between September 2014 and October 2016. Patients showing poor response to α1 blockers for benign prostate hyperplasia (BPH) were eligible for this study. Tadalafil was administered in exchange of the α1 blocker. Demographic data, I-PSS, I-PSS QOL, IIEF-5, uroflowmetry (UFM), post-voiding residue (PVR), prostate volume (by transabdominal ultrasound), PBP, and axial brachial index (ABI) were evaluated before and at 4 and 12 weeks after switching to tadalafil. The relationship between I-PSS scores and PBP was examined in these patients. To measure PBP, a cuff for the big toe was wrapped around the penis. This study was approved by the institutional review board.

Results

A total of 55 patients were eligible. Within 4 weeks after switching to tadalafil, 3 patients dropped out of the study because of adverse events and another three dropped out because of worsening LUTS. Overall, 49 patients tolerated tadalafil for the entire 12 weeks and were investigated. Median age was 74 years. 25 patients with PBP less than 110 mmHg at baseline responded better to tadalafil, with improvement of I-PSS at 12 weeks compared to those with higher PBP (p= 0.006, Figure). Lower PBP at baseline was significantly associated with improved I-PSS by tadalafil at 12 weeks on uni- and multivariate analyses (p<0.001 and p=0.001, respectively). On multivariate analysis, improved I-PSS was also related to previous anticholinergic drug use (p=0.021).

Conclusions

This study demonstrated that PBP could reliably identify BPH patients who could benefit from tadalafil treatment. Especially in cases with PBP <110 mmHg, we can consider changing administration to tadalafil.

Funding

none