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

Abstract

Study Type – Therapy (case series) Level of Evidence 4 What’s known on the subject? and What does the study add? Intraprostatic injection of botulinum toxin type A was shown to be effective in decreasing symptoms of BPH in several recent studies. However, the possible impairment of sexual function caused by the neurotoxin had never been investigated. This study shows that intraprostatic administration of botulinum toxin type A neither causes deterioration of sexual function (libido, orgasm, erectile function or ejaculation), nor alteration of serum testosterone levels. 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 (Qmax) <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.

Patient‐reported outcomes in men with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH) treated with intraprostatic OnabotulinumtoxinA: 3‐month results of a prospective single‐armed cohort study

“…[ 41 ] , we confi rmed in the present study that intraprostatic BTX-A injection in patients with BPH does not impair erectile, orgasmic or ejaculatory functions and does not change libido. This is of utmost importance because sexual dysfunctions commonly occur in parallel with BPH [ 42 ] and are often associated with α -blockers and 5-ARIs.…”

Treating Benign Prostatic Hyperplasia with Botulinum Neurotoxin

“…Intraprostatic injection of BoNT-A in patients with BPH does not impair erectile, orgasmic or ejaculatory functions and does not change libido [84]. The male hormonal profile is not altered by BoNT-A injection.…”

New intraprostatic injectables and prostatic urethral lift for male LUTS

“…However, the studies have shown no consistency in clinical response in terms of outcome parameters such as symptom scores (for example, the American Urological Association Symptom Index [AUASI] and the International Prostate Symptom Score [IPSS]), reduction in prostate volume, postvoid residual urine volume, peak urinary flow rate (Q max ) and PSA (Table 1). [62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79] One intriguing finding is the observation that, even without a relevant impact on prostate volume in selected patients, the application of BoNT-A resulted in an increase in peak urinary flow rate and amelioration of LUTS. 65 This observation highlights the various pathophysiological aspects underlying LUTS suggestive of BPH.…”

“…Interestingly, the intraprostatic injection of BoNT-A does not seem to impair erectile, orgasmic and ejaculatory function. 64,78 One study even reported a significant improvement in ejaculatory function with no change in erectile function after injection of BoNT-A. 81 Adequately powered, randomized, placebo-controlled and blinded clinical trials are required to address essential aspects of BoNT-A treatment, such as the preferred route of administration (transperineal, transrectal or transurethral), optimal sites of injection, dose-dependent efficacy, long-term outcomes and safety profiles, which have not yet been defined.…”