Alprostadil is the generic version of the erectile dysfunction medications Caverject, MUSE, Vitaros and Viridal, although they do not all come in the same forms. For example, Caverject and Viridal are directed directly into the penis, Vitaros is applied as a cream to the penis and MUSE is a urethral suppository (placed inside the penis). As such, the contraindications (interactions with pre-existing conditions) will often differ between the products.

Alprostadil and the branded versions of it belong to a group of medications known as Prostaglandin E1 (PGE1), which are different to the other main type of ED treatment, PDE5 inhibitors (the most well known of which is Viagra). While PDE5 inhibitors are highly useful for many men, these oral treatments may not be as suitable or effective as alprostadil medications in some.

Erectile Dysfunction treatments and contraindications

Contraindications exist for all medications and those relating to erectile dysfunction are no different. PGE1 treatments, however, are generally well tolerated and do not interact with many pre-existing conditions or their related medications. This is partly because they are applied to a specific area, the penis, rather than absorbed into the bloodstream after being taken orally, as is the case for PDE5i treatments such as Cialis. Should one form of alprostadil prove unsuitable, your prescribing doctor may suggest another or even lower the dosage to see if the issues you have with the treatment subside without reducing its effectiveness.

Contraindications for PGE1 treatments

It is essential that you inform your doctor about any drugs you are taking currently or have recently taken, any allergies or intolerances that you have or any conditions that you are experiencing or are prone to. Only then can your treatment be safely prescribed and properly managed. Your doctor should be able to inform you of any risks involved with the treatment and you can always refer to the patient information leaflet that comes with your medication, which lists all known contraindications and side effects.

As there are several different types of alprostadil based medications, it’s important to refer to the leaflet for the specific PGE1 treatment you’re using, be it Caverject, MUSE or Vitaros. Because the active ingredient is the same, it’s likely the contraindications will be similar, but there may be some that relate more to how the medicine is administered.

MUSE and Caverject contraindications include: allergies to alprostadil or any of the other ingredients of this medicine, sickle cell anaemia, leukaemia, multiple myeloma, priapism, implants in your penis, conditions where sexual activity should be avoided, a history of or susceptibility to blood clots, heart problems, had a stroke, inflammation of the penis, or a penis that is scarred or significantly bent and tight foreskin.

If any of the following conditions apply to you, your doctor may suggest another treatment: lung, chest or heart disorders, a history of mental illness or addiction, mini-strokes, cardiovascular risk factors or risk factors for strokes. 

Other reasons you may not be prescribed alprostadil

Not all reasons for these drugs being unsuitable relate to pre-existing conditions. Your doctor may decide that these treatments are not suitable for you for a number of reasons. This is why your doctor will ask you about your personal circumstances to see which is the best course of action for you. It is important to be as honest as possible during this consultation. Some of the most common reasons why your doctor may consider medications such as MUSE unsuitable (or likely to be ineffective) include being in a difficult relationship, having alcohol or drug issues and not suffering from erectile dysfunction.

Difficult relationships

All relationships are different and dealing with the issues that come up can be extremely difficult. Such emotional pressures can put a huge strain on a relationship, and it is common in these circumstances for erectile dysfunction to occur. Talking therapies, including counselling, have been proven to be a much more effective way of dealing with these issues than medication.

Alcohol and drug issues

Common causes of erectile dysfunction are alcohol and drug abuse. In these cases, it is likely that your doctor will want to address these underlying issues before tackling the conditions they cause. Alcohol and drug use can also lead to these medications becoming ineffective, so treatments such as Viridal will often be seen as purposeless in these circumstances.

Not suffering from erectile dysfunction

When PDE-5 inhibitors such as sildenafil and vardenafil were released onto the market, they were widely reported in the press as a breakthrough in the treatment of erectile dysfunction. However, many wrongly believe that the medication acts as an aphrodisiac or aid for sexual performance. Therefore, your doctor will not be able to prescribe these medications unless you suffer from erectile dysfunction.

Minimising the risks

There are several things you can do to minimise the risk of contraindications, not to mention side effects, from PGE1 medications such as Caverject, MUSE and Vitaros. Ensuing that your prescribing clinician knows of all other treatments you are currently taking or have recently taken, including supplements and herbal medications, is essential. As is providing all the relevant information on any conditions you have or are prone to.

It is also vital that you do not buy these medications online from disreputable sources. All PGE1 treatments for ED, at time of writing, require a prescription from a doctor or clinician. So you shouldn’t trust a site offering them on a ‘no prescription required’ basis. Check to see that the site you’re using is registered with the GPhC before ordering treatment, or revealing any personal info.

Page last reviewed:  23/07/2020