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Bimix vs. Trimix: How They Work to Treat Erectile Dysfunction
Erectile Dysfunction

Bimix vs. Trimix: How They Work to Treat Erectile Dysfunction

Bimix vs. Trimix—these two medications are both penile injectables that treat erectile dysfunction (ED). Trimix is a well-established medication used as a second-line ED treatment for men who cannot take phosphodiesterase class 5 (PDE-5) inhibitors such as Cialis and Viagra, have side effects when taking these medications, or have not had satisfactory results from PDE5 inhibitors.1 Trimix comprises three medications that work synergistically to increase blood flow into the penis. Bimix is a combination of two of these medications. Younger men with ED more commonly use it.

What is the difference between Trimix and Bimix injections?

Trimix is a mixture of three medications: papaverine, phentolamine, and prostaglandin. Bimix is made up of papaverine and prostaglandin. These medications can be used in varying concentrations, which allow for a wide range of options and make it possible to customize penile injection therapy for each patient.

The goal of treatment is to use the minimum effective dose that helps a man get and maintain an erection suitable for penetrative sex. Trimix has been shown to be about 80% effective in helping men get and maintain an erection.1 It does not impact libido, prevent pregnancy, or protect against sexually transmitted diseases.

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Which is better, Bimix or Trimix?

Bimix and Trimix are similar. They both contain papaverine and phentolamine. To make Trimix, prostaglandin is added. Most men are prescribed Trimix to start treatment and move to Bimix if they are sensitive to prostaglandin. One of the benefits of using penile injections is that the medication dose can be customized for each man. Also, systemic medication side effects are minimized by injecting the medication directly into the penis.

How long does it take for Bimix to work vs. Trimix?

Trimix and Bimix should produce an erection within 5 to 20 minutes, and an erection should last for about 30 to 60 minutes.

How often can you use Bimix compared to Trimix?

Trimix and Bimix should never be used more than once in a 24-hour period, more than two days in a row, or more than two to three times a week. Using Trimix or Bimix with oral ED medications increases the risk of adverse effects, such as priapism. Advise your healthcare provider if you have taken any oral ED medications in the week prior to the intended use of Trimix or Bimix.

Who should not take Bimix or Trimix?

Trimix should not be prescribed for people who:2 

  • Have a hypersensitivity or an allergy to any component in the formulation.
  • Have a condition that predisposes to priapism (a painful erection lasting over 4 hours).
  • Have sickle cell anemia, multiple myeloma, or leukemia.
  • Have an anatomical deformity of the penis.
  • Are taking any medications that interfere with blood clotting.
  • Have a condition with which sexual activity is not advised.

What are the potential side effects of Bimix and Trimix?

Many people are surprised to learn that Trimix and other penile injectables are so popular because the idea of injecting a medication into the side of the penis seems a bit overwhelming.

Research studies

In a large study that surveyed men taking penile injections, only 4.9% discontinued treatment due to pain from the injection.2  

In another study of 65 men, on a score of one to ten, men rated the pain from injection a 0.8/10 with a range of 0-3, and 40 percent reported no pain. Study participants rated the pain from the medication being injected as 1 out of 10, with a range of zero to five, with 64.6 percent reporting no pain.3

In another study, 12-15% of men reported pain with injection. Most men reported decreased pain throughout treatment.4  

In one study of 116 men in whom both oral ED and penile injectables were successful, one-third of the men preferred penile injectables over oral medications.5

Prostaglandin in Trimix tends to correlate the most with the degree of erectile firmness, but it is also the medication most likely to cause a stinging or burning sensation, especially in people with prostaglandin sensitivity. This would be a good reason to switch to Bimix because you would still get the benefits of papaverine and phentolamine without the side effects of prostaglandin.

Side effects

The most common side effects associated with Trimix use include:

  • Stinging, pain, or soreness at the injection site: usually temporary but may require switching to Bimix
  • Slight bleeding: applying pressure after injection can mitigate this issue
  • Bruising: learning the best injection techniques can help reduce bruising
  • Infection: good hygiene and injection techniques can reduce infection risk

Less common side effects include:

  • Diarrhea, nausea, stomach cramps, or vomiting
  • Allergic reactions: hives, swelling, itching
  • A sudden drop in blood pressure
  • Increased heart rate
  • Abnormal heart rhythm
  • Fibrosis or scarring at the injection site

Other potential side effects of Trimix include the following:

  • Priapism is an erection that has lasted more than four hours. Untreated priapism can damage the structure of the penis
  • Fibrosis or scarring of the penis
  • Pain or redness at the injection site
  • Lumps, swelling, tenderness, or curvature of the erect penis

The most serious Trimix injection side effects tend to result from too high a dose or overuse—injecting Trimix more frequently than the prescribing instructions state. Follow the directions carefully and ask questions if anything is unclear.

A man looking at a computer screen

The American Urological Association advises men to take ED seriously because it can be a precursor to future cardiovascular disease. They advise men to consider and discuss all ED treatment options in order to determine which class of medications has the best risk versus benefit profile.

Still have questions about Bimix and Trimix and their risks and benefits? Connect with one of the treatment specialists at Invigor Medical to learn more about these medications and others that can treat ED. Trimix and other ED medications require a prescription.

Learn more about buying Trimix injections online.


While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider.  You should always consult a practicing professional who can diagnose your specific case.  The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice. 


1. Coombs, P. G., Heck, M., Guhring, P., Narus, J., & Mulhall, J. P. (2012). A review of outcomes of an intracavernosal injection therapy programme. BJU International, 110(11), 1787–1791.

2. McVary, K. (2010). Contemporary Treatment of Erectile Dysfunction: A Clinical Guide. United Kingdom: Humana Press.

3. Albaugh, J. and Ferrans, C.E. (2009), ORIGINAL RESEARCH—ED PHARMACOTHERAPY: Patient‐Reported Pain with Initial Intracavernosal Injection. The Journal of Sexual Medicine, 6: 513-519.

4. Bennarchik, C. Kottwitz, M. & Geiger, S. (2010). Self-injection, Transurethral, and Topical therapy in Erectile Dysfunction.

5. Bennarchik, C. Kottwitz, M. & Geiger, S. (2010). Self-injection, Transurethral, and Topical therapy in Erectile Dysfunction.

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Published: Jun 15, 2023


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