Sexual dysfunction induced by intrathecal baclofen administration: is this the price to pay for severe spasticity management?

Abstract

Introduction: Intrathecal administration of baclofen (ITB) is widely recognized as an effective treatment for severe spasticity of both spinal and supraspinal origin with fewer side effects. The lower drug dosages used for spinal intrathecal administration, acting directly on the receptor sites, result in greater therapeutic efficacy with less systemic toxicity than with oral preparations.

Aim: This study aims to prospectively evaluate the effects of ITB on erectile function in male patients affected by severe spasticity.

Methods: Twenty adult male patients, with a 34.85 ± 10.27 mean age, affected by severe spasticity mainly due to spinal cord lesions (10 traumatic, three vascular, six degenerative, and one congenital in origin) and treated with ITB, were enrolled in the study. All participants underwent specific clinical scales to evaluate force, muscle tone, cognition and mood, and specific sexual questionnaires, including an accurate semi-structured interview.

Main outcome measure: The International Index of Erectile Function (IIEF) was used to evaluate sexual function before and after pump implantation.

Results: A comparative analysis of the neurological scales and psychometric scores at T1 (baseline) and T2 (follow-up) showed statistically significant differences before and after pump implantation. In particular, we noted a significant decrease in the IIEF median scores (from 0.42 ± 0.07 to 0.14 ± 0.02, P value < 0.0001) and a correlation between ITB dosage and IIEF scores (ρ = -0.60; P < 0.05).

Conclusions: This study supports previous findings on a possible negative effect of ITB on sexual function, with regard to erection. Patients who are considering ITB for treatment of severe spasticity should be informed about possible but reversible sexual side effects, especially at higher dosage. Future studies with larger samples should be fostered to confirm these findings for a better management of these, often young, patients.

Keywords: Baclofen; Ejaculation; Erection; ITB; Sexual Dysfunction; Spinal Cord Injury.