Trimix

Trimix is a three-drug compounded injection used directly into the penis for men with erectile dysfunction unresponsive to oral medications. The combination — alprostadil (PGE-1), phentolamine, and papaverine — is the standard second-line treatment for ED after PDE5 inhibitors fail or are contraindicated.¹

How it works

Each component contributes a different vasodilatory mechanism. Alprostadil directly relaxes corpus cavernosum smooth muscle.² Phentolamine blocks alpha-adrenergic receptors that normally cause vasoconstriction. Papaverine inhibits phosphodiesterase. Together they bypass the need for the normal nerve-driven nitric-oxide signal — making Trimix effective even in men with neurogenic ED (e.g., post-prostatectomy) or severe vasculogenic causes where PDE5 inhibitors don't work.³

Who it is for

Men with ED who have failed an adequate trial of PDE5 inhibitors, or who cannot take them due to nitrate use or other contraindications. Often the right choice after radical prostatectomy with cavernous nerve injury, severe diabetic neuropathy, or significant arterial insufficiency. Initial dose titration happens in clinic so the provider can confirm response and rule out priapism risk.

What to expect

Self-administered injection with a fine-gauge needle into the lateral corpus cavernosum, 5–15 minutes before intended activity. An erection develops within 5–20 minutes and typically lasts 30–90 minutes — longer if the dose is too high. Most men adapt quickly to the technique with brief in-clinic training. Effectiveness rate exceeds 90% with appropriate dose titration.

Important considerations

• Priapism (erection lasting >4 hours) is the most important risk. Patients must know how to recognize and respond — go to an ER. Risk is highest during initial titration.
• Penile fibrosis can develop with long-term use; rotation of injection sites and proper technique mitigate it.
• Bruising at the injection site is common but minor.
• Compounded only; not FDA-approved as a combination product (individual components are approved). Quality depends on compounding pharmacy.
• Contraindicated in sickle cell disease, hypercoagulability, or anatomic deformity of the penis.