Intraprostatic botulinum toxin type A administration: evaluation of the effects on sexual function

Abstract

Objective: • To evaluate the consequences on male sexual function of intraprostatic injection of botulinum toxin type A (BoNT/A) as a treatment for benign prostatic hyperplasia (BPH). Although BoNT/A is effective in decreasing symptoms of BPH, neuronal impairment caused by the neurotoxin might affect emission/ejaculation. These aspects have not been evaluated before.

Patients and methods: • In all, 16 sexually active men aged >60 years with BPH/benign prostatic enlargement (BPE), International Prostate Symptom Score (IPSS) ≥8 and a maximum urinary flow rate (Q(max)) <15 mL/s refractory to standard medical therapy volunteered for the study. • Patients were injected transrectally, under ultrasonographic control, with 200 U of BoNT/A in the prostate. Evaluation was carried out at baseline and 1, 3 and 6 months post-treatment. Erectile function was evaluated using the International Index of Erectile Function - Short Form (IIEF-5) questionnaire. • Orgasmic/ejaculatory function and libido were evaluated using questions 9, 10, 11 and 12 of the IIEF - Long Form. Total testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prolactin were also investigated.

Results: • The mean age was 73 ± 6 years. The IIEF-5 score was 16.5 ± 6 at baseline, 15.7 ± 6 at 1 month, 16.6 ± 6 at 3 months and 15.7 ± 5 at 6 months (differences nonsignificant). • The score for ejaculatory/orgasmic function (questions 9 and 10) remained fairly constant from baseline to the sixth month, 8.3 ± 1.9 and 8 ± 2.1 respectively. • The sexual desire score (questions 11 and 12 of the IIEF) also remained little changed from baseline (5.9 ± 1.6) to month 6 (6.1 ± 2). Total serum testosterone, LH, FSH and prolactin did not change during the study.

Conclusions: • Intraprostatic injection of BoNT/A in patients with BPE does not impair erectile, orgasmic or ejaculatory functions and does not change libido. • The male hormonal profile is not altered by BoNT/A injection. This facilitates the acceptance of BoNT/A as a treatment for BPH/BPE lower urinary tract symptoms (LUTS) refractory to standard medical management.