El-Shaer · Andrology 2021 · Randomized double-blind placebo-controlled trial · n=176

Intra-cavernous injection of BOTOX ® (50 and 100 Units) for treatment of vasculogenic erectile dysfunction: Randomized controlled trial.

Cited 35 times in the scientific literature.

Level 2 - randomized trial

Prospective randomized double-blind placebo-controlled trial

PubMed 33784020 · doi:10.1111/andr.13010 · record verified 2026-08-28

What was done

In a prospective, randomized, double-blind, placebo-controlled trial conducted from 2016 to 2019, 176 patients with vasculogenic erectile dysfunction refractory to phosphodiesterase-5 inhibitors and/or intracavernosal trimix were assigned (1:1:1) to receive a single intracavernosal injection of onabotulinum toxin-A 100 U (n = 62), 50 U (n = 59), or saline placebo (n = 55). Patients were followed for 6 months using SHIM, Erection Hardness Score, Sexual Encounter Profile, Global Assessment Score, and penile Doppler ultrasonography.

What was found

Both the 50 U and 100 U Botox groups showed statistically significant improvements across all clinical and Doppler parameters compared to baseline (p < 0.001), peaking at 3 months post-injection. Approximately 40% of treated patients responded and were able to engage in sexual intercourse. Placebo recipients showed no significant improvement (p = 0.264). Outcomes did not differ significantly between the 50 U and 100 U groups at 2 weeks or 3 months (p > 0.05), but at 6 months the 100 U group maintained significantly better scores than the 50 U group (p < 0.01).

Why it matters

This trial provides randomized evidence that intracavernous botox injection is an effective and safe intermediate option for men with severe vasculogenic ED who fail oral or traditional injection pharmacotherapy, potentially delaying or avoiding penile prosthesis surgery.

Limits

The abstract does not report baseline or absolute follow-up numeric scores (such as mean SHIM or peak systolic velocities), specific adverse event counts or rates, or findings beyond 6 months to assess when the effect fully wanes or whether repeat injections remain safe and effective.

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