Login to Access Video or Poster Abstract: MP91-20
Sources of Funding: This study was funded with grants from the Manitoba Medical Services Foundation and the Health Sciences Centre Foundation.

Introduction

Men with spinal cord injury (SCI) commonly have erectile dysfunction, for which PDE5 inhibitors can have good effect in treating. People with SCI above thoracic-6 (T6) are prone to hypotension. Side effects of PDE5 inhibitors can include hypotension. Thus our goal was to determine the effects of tadalafil 20 mg compared to placebo on blood pressure (BP), heart rate (HR), and dizziness of men with complete American Spinal Injury Association Impairment Scale-A (AIS-A) SCI between cervical-4 (C4) and thoracic-5 (T5), and how long these effects last.

Methods

This was a double blind, randomized cross-over placebo-controlled study of 20 males with AIS-A SCI, C4-T5. Subjects received either tadalafil or placebo for the first arm, then were crossed-over after 1 week to the second arm. BP, HR, and Visual Analogue Scale (VAS) for dizziness upon sitting up from laying were measured at baseline and again 1, 2, 4, 12, 22, 29, and 36 hours post each dose administration. The change in each outcome measures (systolic BP, HR, VAS) was observed from pre-dose to each time point. A change at any point in VAS of 2cm or greater (scale 0-10cm) was considered positive.

Results

Systolic BP did not change significantly in either group. However, HR increased significantly in the tadalafil group at several time points (12h p>0.05, 22h p>0.05, 29h p>0.01, and 36h p>0.05), with no change in the placebo group. The VAS for dizziness significantly increased (range 2-6cm change) at some time point in 1/4 of the subjects after tadalafil but not in the placebo group; all reports of dizziness were at 12 hours or later.

Conclusions

It appears that tadalafil use in people with SCI above T6 is safe with respect to not causing hypotension; hemodynamic changes that occur 12-36 post administration are compensated for by elevations in HR. This should be further investigated with larger sample sizes, focusing on the tetraplegic population, as those without spinal cord sympathetic outflow may not be able to have adaptations in HR to maintain BP.

Funding

This study was funded with grants from the Manitoba Medical Services Foundation and the Health Sciences Centre Foundation.