Alprostadil is the generic version of Caverject, MUSE, Viradil and Vitaros. They are part of a group of medications called Prostaglandin E1 (PGE1) treatments for erectile dysfunction that are seen as a viable alternative to the PDE-5 inhibitor medications such as Viagra and Cialis.

Side effects for Alprostadil treatments tend to be mild and some might find they have less issues with toleration than other types of erectile dysfunction medications. This may depend on how the treatment is administered, such as via an injection (Caverject) or cream (Vitaros), but it is not possible to predict which treatment will work with the least issues for you before trying them.

Clinical trials

Prostaglandin E1 was first isolated in the 1950s, but it was not until 1982 that it was first used as a treatment for erectile dysfunction, providing positive results that had until this point been unavailable to those with the condition.

With the introduction of newer forms of treatment, including PDE5 inhibitors such as Viagra and Levitra in the late 1990s and throughout the 2000s, alprostadil medications were seen to be less effective and convenient, leading to their use dropping dramatically. It soon became apparent, however, that some patients didn’t respond to PDE5 inhibitors in a positive way. As many as 30% ceased treatment within six months, which was thought to be unrelated to their effectiveness. This suggested a minority of issues with toleration, leading to successful treatments with drugs such as Viridal Duo. These older types of erectile dysfunction treatments remain an important option, sometimes used in combination with the newer treatments.

Side effects and administration

Unlike PDE5 inhibitors, such as Spedra, alprostadil medications are not administered orally. Typically, they are applied as creams or injected into the penis, with MUSE being inserted into the tip via the urethra. As such, side effects for these medications will differ to some degree relating to the form they come in. For example, Caverject can cause irritation at the site of the injection. To avoid scarring issues, you should change the injection site each time you use it. For creams, such as Vitaros, skin reactions are more likely to occur.

Should you experience side effects that relate to the administering of treatment you can speak with your doctor, who will be able to provide advice to minimise these risks or change treatment to another form if necessary.

Frequency of Caverject side effects

As previously mentioned, side effects will depend on the drug itself as well as the method of administration. The following information, therefore, might not be relevant for your specific treatment. The following side effects relate to the injectable erectile dysfunction Caverject. If you have any questions regarding side effects, your prescribing clinician should be able to provide you with all the information you need. You can also refer to the patient information leaflet that comes with your medication, which lists all known side effects and their frequency.

Discontinue use of this treatment and seek immediate medical attention if you experience an erection that lasts for longer than four hours. If you cannot contact your doctor, go straight to the emergency room as it will need to be treated within six hours of the initial dosage.

Other side effects include:

Very common (may affect more than 1 in 10 people): pain in the penis

Common (may affect up to 1 in 10 people): bruising of the penis, scarred, bent or kinked, penis after long term use, prolonged erections, swelling and skin discolouration at the injection site and muscle spasms.

Uncommon (may affect up to 1 in 100 people): the injection site becoming irritated, inflamed or swollen or itching or bleeding, or feel numb, warm, tender or painful, the testes or scrotum could become red, swollen or painful, or develop lumps, numbness, painful or prolonged erections, changes in ejaculation, foreskin and head of the penis could feel tight or swollen, frequent urination, blood in the urine, pelvic pain, weakness, sweating, feeling sick or swollen legs or arms, common cold symptoms, dry mouth, thrush, changes in blood pressure, heart rhythm issues, faintness, shallow breathing, skin itching, increased sweating, sensitivity to bright light, excessive dilation of the pupil, impaired sense of touch, leg cramps, cold hands and feet, bleeding from veins and raised levels of creatinine.

Not known (frequency cannot be estimated from available data): Insufficient blood flow to the heart muscle and stroke.

Minimising Caverject side effects

There are many ways in which you can minimise the risks of side effects occurring, the most important of which is by properly following directions. It is essential that you do not increase the dosage of these mediations as this can greatly enhance the risks involved. If you are not getting the results you require from alprostadil you should speak with your doctor about the options available to you. This may include increasing the dosage or trying a different medication or form of prostaglandin E1 treatment.

For Caverject, changing the site of injection each time you use it can minimise skin irritation and scarring.

For a cream like Vitaros, using the treatment immediately after opening can ensure that you get the most from the medication, making it less likely that a stronger dosage will be required.

For urethral stick medications, in drugs such as MUSE, gentle and slow application can avoid irritation and pain. Not using any of these medications more often than is prescribed is also vital for minimising side effects.

Reporting side effects

If you are experiencing side effects that are causing you discomfort, you should tell your doctor so they can adjust your treatment accordingly. With so many options regarding treatments for erectile dysfunction, it is likely there is a dosage, form or type of medication to suit you.

You can also report side effects to the MHRA’s (medicine healthcare products regulatory agency) Yellow Card Scheme, which tracks issues with healthcare treatments and products. This helps to properly list side effects and accurately inform patients of the risks involved.

Page last reviewed:  24/07/2020