Caverject was a brand of injectable alprostadil treatment that was available as a dual chamber injection and in individual vials. The vials were used in the same way as generic Alprostadil, while the dual chamber device helped mix the solution for ease of use. It was discontinued early in 2025 after a period of stock shortages.
If you’re after Caverject alternatives, you’ve got a couple of options. Generic Alprostadil contains the exact same active ingredient as Caverject, and is used in the same way as Caverject vials. And if you liked the ease of Caverject Dual Chamber, Viridal Duo is another Alprostadil treatment that comes in a similar easy-to-use syringe.
Do you need a prescription for Alprostadil?
It’s not possible to get Alprostadil without a prescription in the UK. Being a prescription only treatment allows your doctor to properly monitor its use and adjust or change your treatment if needed. Alprostadil prescriptions are only given when your prescribing clinician thinks it safe for you to use.
How to use Alprostadil
There are two different kinds of alprostadil injection available to choose from: generic Alprostadil powder (which comes in vials) and Viridal Duo. The instructions are different for each type, so be sure to follow the correct one for your treatment as you’ll need to know how to correctly mix Caverject powder for the injection. Pfizer provides Caverject instructions with each product, so you can always refer to these if you’re not sure.
Using Viridal Duo can be easier for some as it comes with the device that mixes the powder and solution by pushing the plunger. You just need to attach the needle, push the grey plungers together, then gently shake the mixture before use.
To inject Alprostadil powder you’ll need to fix a needle onto the syringe containing a solution to dissolve the powder – then pierce the syringe through the top of the Alprostadil vial, and push the plunger. After giving it a gentle swirl the mixture should become clear. If the mixture remains cloudy you shouldn’t use it. Draw out the mixture into the syringe by pulling the plunger and it’s ready to use.
For Alprostadil administration, try to relax before using it. You can start by undressing and lying on your bed. Swab the injection area with the antiseptic pad then gently hold your penis from the front at a slight angle so that the injection area, the side of the penis, sticks out.
Taking care to avoid any veins, push the needle into the bulging part of the shaft and slowly press the plunger without forcing the solution. The Caverject needle size will be long enough to reach the area it’s designed for, just be sure that it’s not bent before use.
For full information about how to use Alprostadil, your medication will come with a package insert with all the information you need. Your doctor will make sure you know how to use Alprostadil before prescribing the treatment, so this should only act as a backup.
If you’re still unsure about how to administer alprostadil in either of its forms, speak with your prescribing clinician.
Where does Alprostadil need to be injected?
Now we’ve explained how to inject Caverject, here’s a little more information on the Caverject injection site. This is important as the medication will not work as it should if this aspect of the process is incorrect.
Along the shaft of the penis (the part that leads up to the head) runs two parallel chambers called the corpora cavernosa. It’s here that you need to inject Caverject, past the outer layer of skin.
There is little difference between how to inject Alprostadil vials and Viridal Duo after mixing the powder and solution.
Does Alprostadil need to be refrigerated?
Alprostadil doesn’t need to be refrigerated as it comes in a powdered form, but once you’ve mixed it with the solution, it needs to be used straight away in the case of the vials.
Vials should be used within three months from when you’ve been provided with the medication. Always check the use by date before injecting Caverject.
Can you use Alprostadil and Viagra together?
Despite the fact that they’re different medications, you shouldn’t take alprostadil and Viagra together. When combined these drugs lower blood pressure even further than they would separately, causing dizziness, a rapid pulse and fainting.
Taking alprostadil and Viagra together also won’t provide any benefits. If one drug isn’t working by itself, then trying the other separately is the only way to know if it’s a good replacement. You should speak with your doctor if you want to change your erectile dysfunction medication.
How much Alprostadil should I use?
Everyone is different and how they process any medication is unique to them. Some men find that the lowest dosages of Alprostadil are effective and that they won’t need to take the higher ones. Others might have toleration issues with the standard dose and lowering still provides the benefits of the medication without the side effects.
Prescription dosages typically start between 1.25mcg and 2.5mcg. These are very low dosages that are prescribed to see if you are able to tolerate it. If all goes well, your doctor will begin titration, which is where the dosage is increased slowly to see which strength allows you to get the maximum benefits from the medication with the minimum of side effects.
Most men will find that a dosage of between 5mcg and 20mcg is effective enough to treat their erectile dysfunction. You should be able to find the right dosage for you, with a little patience and guidance from your prescribing clinician.
How well does Alprostadil work?
Alprostadil results from various studies show that the majority of men will gain significant benefits from the treatment. One study reported satisfaction rates at 87% in the men that participated. Alprostadil doesn’t always work for every man. This can be for several reasons, including the cause of the condition and its severity.
When comparing alprostadil vs Viagra, Viagra is preferred by most men, but many found that alprostadil worked best for them. This suggests some trial and error is recommended if you’re having issues with one or other of the treatments. Oral PDE5 inhibitors will usually be the first line of treatment for men with ED but it’s important to note that there are several other non-oral options available.
So how long do alprostadil and Viagra last? You should be able to get the benefits of alprostadil for up to an hour, which is shorter than Viagra at five hours.
Alprostadil does not increase your size and it cannot cause arousal. It’s prescribed to help you achieve erections during sex. None of the erectile dysfunction treatments have aphrodisiac properties.
If alprostadil doesn’t work for you, always remember that there are many other options available. These include alprostadil creams and suppositories as well as oral treatments such as Viagra, Cialis, Levitra and Spedra.
How long will my erection last using Alprostadil?
Like other erectile dysfunction treatments, Alprostadil only works if you’re sexually aroused – so it won’t work if you’re not ‘turned on’. But if you are then there’s a good chance your erection will last for a long as you need it to. Occasionally some men can have prolonged erections when using injectable ED medications. This can be serious, so only use the dose prescribed for you by your doctor.
If your erection persists, becomes painful or lasts longer than four hours, you need urgent medical attention so call 999 or get yourself to the local A+E department straight away.
The 
