(287) INTRACAVERNOSAL BOTULINUM TOXIN USE IN THE TREATMENT OF ERECTILE DYSFUNCTION: A PROSPECTIVE, DOUBLE-BLIND, RANDOMIZED STUDY
Authors: Moreira Crelier G , Ribeiro Julio Júnior H , De Teófilo E Figueiredo Filho R , Borges Carrerette F , Mario Costa Lara C , Luiz Schiavini J , Damião R 
Published: December 2024

Abstract

Introduction
Erectile dysfunction (ED) is a significant public health issue that greatly impacts patients’ quality of life. Its prevalence increases with age and is associated with several risk factors, including diabetes, hypertension, hypercholesterolemia, smoking, sedentary lifestyle, obesity, and hypogonadism. These factors often lead to vascular endothelial alterations, resulting in atherosclerosis, arterial obstruction, and reduced penile blood flow. Traditional treatments for ED focus on vasodilators to facilitate erections. In the 1980s, intracavernosal injections of vasoactive drugs became prevalent, and the 1990s saw a revolution with the introduction of phosphodiesterase-5 (PDE5) inhibitors, such as sildenafil. Despite their effectiveness, about 30% of patients do not respond adequately to these treatments, prompting the search for more effective alternatives. Botulinum toxin (BT), known for its muscle relaxation properties, emerges as a promising candidate. Preliminary studies, including those by Ghanem (2018) and El-Shaer (2021), show promising results for intracavernosal BT in ED treatment, though further research is needed.

Objective
The primary objective of this study is to determine the safety and efficacy of intracavernosal botulinum toxin application in the treatment of erectile dysfunction. Specifically, the study aims to assess the improvement in erectile function in patients with ED refractory to standard treatments and evaluate the occurrence of any adverse events associated with BT use.

Methods
This prospective, double-blind, randomized study involves evaluating botulinum toxin (study drug) versus placebo, alongside standard ED treatments. The study includes male patients aged 18 and above, with an International Index of Erectile Function (IIEF-5) score of 21 or less, and currently undergoing at least one form of standard ED treatment. Exclusion criteria include urogenital neoplasms, radical prostatectomy, testosterone levels below 350 ng/ml, diagnosed depression on antidepressants, genital tract anatomical alterations, and insufficient sexual activity for analysis. Participants will be randomly assigned to either the BT or placebo group. The active treatment involves injecting 100 units of botulinum toxin, diluted in 4 ml of 0.9% saline, into the penile base and distal shaft, with a penile base tourniquet applied for 20 minutes. The placebo group will receive 0.9% saline injections. Patients will be monitored for 12 months, with evaluations at 1, 3, 6, and 12 months post-treatment. These evaluations include the IIEF-5 score, penile length (CRT max), and blood tests. After 6 months, the blind will be lifted, allowing placebo group patients to opt for BT treatment, and active group patients to receive another BT dose if desired.

Results
Initial findings from the study indicate that of the 15 patients treated, 8 have shown improvements in their IIEF-5 scores. However, it is important to note that the study is still blinded, and we do not yet know which patients receives botulinum toxin and which received the placebo. As such, the observed improvements cannot yet be attributed to the botulinum toxin treatment. The study will continue the 6-month mark, at which point the blind will be lifted, allowing for a more precise evaluation of the treatment’s efficacy. To date, the treatment has been well-tolerated, with no severe adverse events reported, aligning with previous research on the safety and efficacy of BT for ED.

Conclusions
This study provides evidence supporting the uso of intracavernosal botulinum toxin as a safe and effective treatment for erectile dysfunction, particularly in patients who do not responde to conventional therapies. The results indicate improvements in erectile function and minimal adverse effects, suggesting that BT could become a valuable addition to the current ED treatment options. Further research with larger sample sizes and longer follow-up periods is necessary.

Disclosure
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