Caverject for Erectile Dysfunction Explained

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Caverject for Erectile Dysfunction: How Penile Injections Work

Published: 15 October 2026

Caverject for erectile dysfunction is a prescription-only treatment containing alprostadil, a medicine injected directly into the penis to produce an erection. It is typically considered when oral tablets (PDE5 inhibitors) have not worked, are unsuitable, or cause unacceptable side effects. Caverject works differently from tablets and may be an option for men who need a more direct approach to achieving an erection.

What is Caverject for erectile dysfunction?

Caverject is the brand name for alprostadil, a synthetic version of a naturally occurring substance called prostaglandin E1 [7]. It is administered as a small injection into the side of the penis, directly into the corpus cavernosum (the spongy tissue that fills with blood during an erection). Unlike oral tablets, which require sexual stimulation and work by enhancing the body's natural response, Caverject acts locally to relax smooth muscle and widen blood vessels in the penis, producing an erection within 5 to 20 minutes regardless of sexual arousal [7].

Alprostadil is available in other forms, including Vitaros (a topical cream applied to the tip of the penis), but Caverject injections are generally more effective and are often used when other treatments have failed [7]. The injection is given using a very fine needle and a pre-filled syringe or auto-injector device. Caverject is prescription-only in the UK and is usually initiated under specialist supervision, such as by a urologist or specialist nurse, who will teach you the correct injection technique and determine the appropriate dose [2][7].

How does Caverject work for erectile dysfunction?

Caverject works by directly relaxing the smooth muscle in the walls of the blood vessels and the corpus cavernosum of the penis [7]. When alprostadil is injected, it increases levels of cyclic adenosine monophosphate (cAMP) inside the smooth muscle cells, causing them to relax. This relaxation allows blood to flow into the penis and fill the erectile tissue, producing a firm erection. Because the medicine acts locally at the site of injection, it does not rely on nerve signals or sexual stimulation in the same way that oral tablets do.

The erection usually begins within 5 to 20 minutes of injection and typically lasts for about 30 minutes to an hour, though this can vary depending on the dose and individual response [7]. One important difference from oral ED tablets is that Caverject can produce an erection even in the absence of sexual arousal, which can be helpful for men with nerve damage (for example, after prostate surgery or in diabetes) or those who do not respond to tablets [2][7].

Who may benefit from Caverject?

Caverject may be suitable for men who have not had success with oral PDE5 inhibitors (such as sildenafil, tadalafil, vardenafil, or avanafil), or for whom tablets are contraindicated—for example, men taking nitrates for angina [2][7]. It is also an option for men with erectile dysfunction caused by nerve damage, such as after radical prostatectomy (prostate removal), spinal cord injury, or poorly controlled diabetes. Because Caverject works independently of the nervous system's usual pathways, it can be effective even when the nerves that control erection are impaired. However, it requires manual dexterity and confidence to self-inject, and some men may find the idea of an injection off-putting. Your doctor or specialist nurse will assess whether Caverject is appropriate for you and provide training on how to use it safely.

Effectiveness of Caverject for erectile dysfunction

Clinical studies have shown that alprostadil injections are highly effective, with success rates often reported between 70% and 90% in producing erections sufficient for sexual intercourse [7][8]. The effectiveness can be higher than oral tablets in certain groups, particularly men with neurogenic ED (nerve-related) or those who have not responded to PDE5 inhibitors. The dose of Caverject is individualised; your specialist will start with a low dose and gradually increase it during supervised sessions until the right dose is found—one that produces an erection lasting about 30 to 60 minutes without causing prolonged or painful erections.

It is important to note that while Caverject is effective at producing an erection, it does not address the underlying causes of erectile dysfunction, such as cardiovascular disease, diabetes, or psychological factors [1][2]. For this reason, it is still important to see your GP to investigate and manage any underlying health conditions. Lifestyle changes—such as stopping smoking, reducing alcohol, losing weight, and increasing physical activity—can also improve erectile function and overall health.

Side effects and risks of Caverject

The most common side effect of Caverject is pain or aching in the penis, which occurs in a significant proportion of men [7]. This is usually mild and temporary. Other local side effects can include bruising, bleeding at the injection site, or the development of fibrous nodules (small lumps) in the penis with repeated use over time. To minimise the risk of scarring, it is important to vary the injection site and follow the technique taught by your specialist.

The most serious risk associated with Caverject is priapism—a prolonged, painful erection lasting more than four hours [7]. Priapism is a medical emergency because it can damage the erectile tissue and lead to permanent erectile dysfunction if not treated promptly. If you have an erection lasting more than two hours, you should seek urgent medical advice; if it lasts more than four hours, go to A&E immediately. Priapism is more likely if the dose is too high, which is why dose titration under specialist supervision is essential. Other rare but serious side effects include dizziness, fainting (due to a drop in blood pressure), and allergic reactions. Always read the patient information leaflet and report any unusual or persistent symptoms to your doctor.

Who should not use Caverject?

Caverject is not suitable for everyone. It should not be used by men with conditions that predispose to priapism, such as sickle cell disease, leukaemia, or multiple myeloma [7]. It is also contraindicated in men with anatomical deformities of the penis (such as severe Peyronie's disease or penile implants) and in those with a history of priapism. Men who have been advised to avoid sexual activity due to heart problems should not use Caverject. Additionally, alprostadil should not be used in combination with other treatments for erectile dysfunction (such as oral tablets or vacuum devices) unless specifically advised by a specialist, as this increases the risk of priapism. Your prescriber will review your full medical history and current medications to ensure Caverject is safe for you.

How Caverject compares with oral ED tablets

Oral PDE5 inhibitors—such as sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Spedra)—are usually the first-line treatment for erectile dysfunction because they are convenient, non-invasive, and effective for many men [2]. These tablets work by enhancing the natural erectile response to sexual stimulation, and they are taken by mouth 15 minutes to an hour before sex, depending on the specific medicine. However, they require some degree of intact nerve and blood vessel function, and they do not work for everyone—particularly men with severe vascular disease, nerve damage, or those taking nitrates.

Caverject, by contrast, works locally and independently of sexual arousal or nerve signals, making it a valuable option when tablets fail or are unsuitable [2][7]. The main trade-off is that Caverject requires an injection, which some men find uncomfortable or inconvenient, and it carries a risk of priapism and local side effects. Oral tablets are generally easier to use and have a lower risk of serious side effects, but they may be less effective in certain situations. Many men try oral treatments first and move to Caverject if needed. Your doctor or specialist can help you weigh the benefits and drawbacks of each approach based on your individual circumstances.

Getting Caverject on the NHS and private prescriptions

Caverject is available on NHS prescription, but access can be limited. NHS prescribing of treatments for erectile dysfunction is generally restricted to men with certain underlying conditions, such as diabetes, prostate cancer (including after surgery or radiotherapy), spinal cord injury, or other specified medical causes [2]. If you meet the NHS criteria, your GP can refer you to a specialist urology or sexual health service, where you will be assessed and, if appropriate, taught how to use Caverject. The initial doses are usually given under supervision to find the right strength and to ensure you can inject safely.

If you do not qualify for NHS treatment or prefer not to wait for a specialist appointment, Caverject can be obtained on private prescription. However, it is essential that the first doses are supervised by a healthcare professional experienced in its use, as incorrect technique or dosing can lead to complications such as priapism or scarring. Private sexual health clinics and some online services may offer Caverject, but you should ensure that any service provides proper training and follow-up. At Cured Pharmacy, we focus on oral ED treatments, which are supplied after an online consultation reviewed by a UK prescriber. If you are considering Caverject, we recommend discussing this with your GP or a specialist urology service to ensure safe initiation and ongoing monitoring.

Oral ED tablets available at Cured Pharmacy

If you are exploring treatment options for erectile dysfunction, oral tablets may be a convenient and effective first step. Cured Pharmacy offers a range of licensed PDE5 inhibitors, all available after an online consultation reviewed by a UK prescriber. These include generic sildenafil from £0.45 per tablet (£0.36 with first-order code Ednew), generic tadalafil from £7.95 (£6.36 with code Ednew), vardenafil from £16.95 (£13.56 with code Ednew), and Spedra (avanafil) from £20.95 (£16.76 with code Ednew). Branded Viagra and Cialis are also available. All medicines are dispensed by our GPhC-registered pharmacy and delivered discreetly to your door. To find out more or to start a consultation, visit our website.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 15 October 2026]
2. National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 15 October 2026]
3. Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [accessed 15 October 2026]
4. European Association of Urology. (n.d.). EAU Guidelines on Sexual and Reproductive Health. https://uroweb.org/guidelines/sexual-and-reproductive-health [accessed 15 October 2026]

Information on this page is for educational purposes only and is not medical advice. Prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting or changing any medication.