Intracavernosal Injections for Erectile Dysfunction: Efficacy, Safety, and Patient Acceptance

Erectile dysfunction is one of the most common diseases among men. Modern pharmacology provides many solutions to relieve unpleasant symptoms.Thus, PDE5 inhibitors have long been proven to be the best for this purpose. Sildenafil, Vardenafil, Tadalafil, and Avanafil are the four PDE5Is that have been granted regulatory approval around the world.

Sometimes, however, these effective drugs do not work. It can be due to low testosterone levels, absence of sexual arousal, or different health issues. In this case, it is worth pursuing other treatments. Intracavernosal injections are second-line therapy that many men with severe ED can consider. This article will discuss intracavernosal injections, their efficacy, safety, and patient acceptance. Read on for details.

ED: Widely Spread Reasons

Due to the high prevalence of severe comorbidities, the treatment of ED requires a thorough medical history and diagnostic evaluation. Each person with erectile dysfunction has a unique combination of symptoms, stress levels, and health concerns. Doctors should develop treatment plans that consider everyone's priorities.

There must be harmony between psychological, hormonal, neurological, vasculature, and cavernosal components for an erection to form correctly. When any of these functions are impaired, ED develops. ED has a complex etiology, although vascular issues are usually at the root of the problem. The leading risk factors for erectile dysfunction are the same as those for atherosclerosis: high blood pressure, diabetes, high cholesterol, and smoking.

What Is Intracavernosal Injection Treatment

Since its introduction in 1983, intracavernosal injections have proven effective even in the most severely affected males. To get an erection, men are instructed to inject medicine straight into the penile erection chambers. Injection therapy is helpful in treating a broad range of erection problems, including those related to blood vessels, nerves, and mental conditions. A patient injects a small dose of medication into the side of his penis. The drug causes the blood arteries to loosen up, increasing blood flow to the genitals. Since the 1980s, this therapy has enjoyed widespread adoption and use.

Prostaglandin E1 (Alprostadil), Papaverine (Papacon), and Phentolamine (Regitine) are the three most widely used treatments. They can be used either alone or in combination. Although Prostaglandin E1 may be mixed with Phentolamine and Papaverine, Alprostadil is the only proprietary intracavernosal injection authorized by the FDA. Automatic injectors have been designed to make the procedure as simple and painless as possible. Such devices also facilitate easy follow-up and allow for prolonged usage.

How It Works

Intracavernosal injection treatment has been shown to be effective, has few side effects, and is well-liked by patients. In most cases, intracavernosal injections are reserved for males without a prior history of Peyronie's disease who have not responded to oral treatments. The most commonly prescribed first-line medication is prostaglandin E1. It causes an erection by increasing cAMP concentrations via modulation of adenylate cyclase. This, in turn, decreases intracellular free calcium via the relaxation of smooth muscle in the arterioles of the corpora cavernosa.

Different amounts of Prostaglandin E1, Papaverine, and Phentolamine are widely used in combination therapy. Injections of new medications or new combinations of medications are always done at the doctor's office so that the patient's progress can be tracked, priapism may be prevented, and the patient can learn a proper injection technique. A fine-gauge diabetic needle is placed at the 2 o'clock or 10 o'clock midshaft location to provide injections. As a reasonably invasive treatment option, ICI injections call for some physical skill on the part of the patient or their caretaker.

Due to the danger of priapism, patient counseling is advised as key, with instruction on ICI administration practices and frequent patient follow-up being equally important. Penile blood flow may be improved with intracavernous injections of medicines that work by relaxing the smooth muscle in the penile vascular system. In 10-15 minutes after the injection, an erection will occur even without a sexual stimulus.

Available Medications and their Effectiveness


Name of the drug


Mechanism of action



Non-xanthine phosphodiesterase inhibitor

Acts as a general PDE inhibitor, elevating levels of both cAMP and cGMP.

Papaverine is a less effective med compared to others.

Hence it is usually combined with stronger medications. Most males can return to normal erection function after receiving either papaverine injections or papaverine injections combined with an alpha-blocker.


Alpha blocker

Helps relax blood vessels, leading to more blood flowing to the genitals.

This medication is only ever prescribed as part of a more complex regimen, such as a Bimix or Trimix.



Alprostadil binds to PGE1 receptors and triggers the cyclic adenosine monophosphate pathway, causing erections. It stops intracellular potassium and calcium flow, relaxing smooth muscles.

This medicine works directly. It is an effective and FDA-approved drug.

In its most common form, Bimix consists of Papaverine and Phentolamine. Patients with autonomic neuropathy and Prostaglandin E1 hypersensitivity, who may have penile discomfort after receiving injections of Trimix or Alprostadil, may find relief in using Bimix, which contains no Prostaglandin.

Available Medications and their Effectiveness

Because it contains three drugs in one, Trimix is a powerful and effective drug. Trimix includes Prostaglandin, Papaverine, and Phentolamine. Using a Trimix, commonly composed of 5-10 g (up to 40 g) of Prostaglandin E1, 0.5-1.0 mg of Phentolamine, and 15-30 mg of Papaverine, decreases the likelihood of suffering pain. However, this procedure may only be performed if your doctor prescribes it.


Each patient will need a unique dosage of the medication. Take drugs as directed by your doctor. The dose you take should be based on the medicine potency. The duration of treatment, the number of doses taken daily, and the amount of time between doses - all vary from one medical condition to the other.

●       The usual Alprostadil dose is the following:

1 to 40 mcg intracavernous injection into the lateral side of the penis given over 5 to 10 seconds.

●       The maximum dose is 3 times weekly, with at least 24 hours between each use.

The medical specialist will calculate the proper dosage for you. Drugs are usually injected ten to thirty minutes before sexual activity. Never give yourself more than one injection in 24 hours. In addition, this medication shouldn't be used more than twice in a row or thrice weekly.

If the recommended dosage is exceeded, the erection will be unnaturally prolonged. Priapism is the medical term for this problem. The penis might suffer lasting injury if the blood supply is suddenly cut off when the erection is not reversed. Don't wait to see a doctor if the erection hurts or lasts more than 4 hours.

Side Effects

Penis pain during erection is the most prevalent adverse effect of injections. About one in ten injections will result in this, and the discomfort will subside after the erection stops.

The list of side effects also includes:

●       incidence of pain in the injection site or during erection;

●       hematoma or ecchymosis;

●       priapism (defined as a painful erection exceeding four hours in duration);

●       scar formation;

●       fibrosis;

●       tissue damage.

Pain, fibrosis, a lack of spontaneity, and anxiety are common causes of dropping out during the first three to six months after starting the treatment.

Side Effects


If you have an allergy to any of the drug constituents, are at risk for priapism, or use anti-clotting medicines, you should not utilize intracavernous injections. You can get in-depth explanations of these warnings and a discussion of your specific case from your urologist.

The medications for intracavernous injections shouldn't be used in patients with the following medical issues:

●       multiple myeloma;

●       leukemia;

●       sickle cell anemia;

●       increased risk of bleeding due to clotting disorder;

●       Peyronie's disease;

●       bent penis during erection;

●       fibrous tissue formation in the penis;

●       sickle cell trait;

●       lymphoid leukemia;

●       deformity in the penis when it is erect.

If you have any of the mentioned conditions, it's important to see a doctor. Because of the potential for interactions, it is essential to avoid taking certain medications just before, during, or after injections. Some medicines may interact negatively with alcohol or tobacco use. You should also talk to your doctor before combining medication with food, drink, or cigarettes.


If other therapy methods, such as modifying one's lifestyle or taking PDE5Is, have failed, intracavernous injections may be an excellent solution. Although some men may be reluctant to try injectable treatment because of the fear of needles. Those who do, usually find that the advantages exceed the slight discomfort of the injection.

Such a method is effective even for severe ED and when a man has injuries and other health issues. The effect takes place quickly and happens even without sexual arousal or stimulation. Common side effects include pain in the injected area and fibrosis. All men who use intracavernous injections are at risk of priapism. Every patient should know that erections lasting more than 4 hours need medical attention. However, the right choice of med and having enough skills to do an injection can help you avoid unwanted consequences.

Read this next

How is the work of Viagra for sex compared to sex shop alternatives
Medically reviewed by Michael K. Milton

Do sex shop Viagra alternatives work

Sex is important for maintaining...

Read more
Best sex pills: Viagra and its legal alternatives
Medically reviewed by Michael K. Milton

Best legal Viagra

Erectile dysfunction can significantly complicate the life of...

Read more
When to Take Viagra Before Sex, and Everything You Need to Know About This Drug
Medically reviewed by Michael K. Milton

How Long Before Sex Should You Take Viagra?

Viagra has become...

Read more
Does Viagra help with sex drive – what to know
Medically reviewed by Michael K. Milton

Can Viagra help with my sex drive?

Viagra is not a...

Read more
The Psychological Impact of Erectile Dysfunction and the Role of Medicinal Treatments
Medically reviewed by Michael K. Milton

The Psychological Impact of Erectile Dysfunction and the Role of...

Read more