Caverject vs Vitaros: Which Alprostadil Treatment Suits You?

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At a glance

What Are Caverject and Vitaros?

Both Caverject and Vitaros contain alprostadil, a medicine that widens blood vessels in the penis to help achieve an erection [7]. Unlike oral PDE5 inhibitors (such as sildenafil or tadalafil), alprostadil works directly at the site, so it doesn't rely on sexual stimulation in the same way—though arousal still helps.

Caverject is supplied as a powder that you mix with sterile water and inject into the side of the penis using a very fine needle. Vitaros is a cream that you apply inside the opening of the urethra (the tube that carries urine) using a single-use applicator. Both are prescription-only medicines in the UK and require training from a healthcare professional before first use [7].

These treatments are often considered when oral tablets haven't worked, aren't suitable, or cause troublesome side effects. Your prescriber will assess your medical history, current medicines, and any conditions affecting the heart or blood vessels before recommending either option.

How Quickly Do Caverject vs Vitaros Work?

Caverject typically works within 5 to 20 minutes of injection [7]. Many men notice an erection forming quite quickly, which can be helpful if spontaneity is important. The injection delivers alprostadil directly into the erectile tissue, so the onset is usually faster than with oral medicines.

Vitaros cream is applied inside the urethra and is absorbed through the urethral lining. It usually takes effect within 5 to 30 minutes [7]. Because it's a topical treatment, the speed of absorption can vary slightly between individuals, but most men find it works within a similar timeframe to Caverject.

Both treatments are faster-acting than many oral ED tablets. For example, sildenafil typically takes about an hour to work, and tadalafil at least 30 minutes. If you need a treatment that works quickly, either Caverject or Vitaros may be suitable, though your prescriber will help you decide which method you're more comfortable using.

Does Food Affect Caverject or Vitaros?

Neither Caverject nor Vitaros is affected by food or alcohol in the way oral tablets can be [7]. Because alprostadil is delivered directly to the penis—either by injection or urethral application—it doesn't pass through the digestive system. This means you don't need to time doses around meals, and a heavy or fatty meal won't delay how quickly the treatment works. However, heavy alcohol can still worsen erectile dysfunction and may reduce the effectiveness of any ED treatment, so moderation is sensible.

How Long Do the Effects Last?

Caverject injections usually produce an erection that lasts around 30 minutes to one hour, though this can vary depending on the dose and individual response [7]. The effect is more predictable than with oral tablets because the medicine acts directly on the erectile tissue. It's important not to use a dose that causes an erection lasting longer than one hour, as prolonged erections can be harmful.

Vitaros cream typically supports an erection for a similar duration—around 30 minutes to one hour after application [7]. The effect is localised and wears off as the alprostadil is metabolised. Because the duration is relatively short with both treatments, they're designed for use shortly before sexual activity rather than providing a longer window like tadalafil (which can last up to 36 hours).

If you experience an erection lasting more than two hours with either treatment, or more than four hours (priapism), you must seek urgent medical help. Priapism is a medical emergency that can cause permanent damage if not treated promptly. Your prescriber will explain how to use the correct dose to minimise this risk.

What you need to know

• Caverject is an injection; Vitaros is a urethral cream—both contain alprostadil and work in 5–30 minutes.
• Neither is affected by food, and both last around 30 minutes to one hour.
• Caverject may cause injection-site pain; Vitaros can cause urethral burning.
• Both are prescription-only and require training on safe use before starting.
• Seek urgent help if an erection lasts more than two hours with either treatment.

Caverject vs Vitaros: Strengths and Dosing

Caverject is available in several strengths, typically ranging from 10 micrograms to 40 micrograms per injection [7]. Your prescriber will start you on a low dose and adjust it based on your response. The injection is given into the side of the penis, and you'll be shown the correct technique during your first consultation or training session. Most men use Caverject no more than once in 24 hours and no more than three times a week.

Vitaros cream contains 300 micrograms of alprostadil per single-use applicator [7]. The dose is pre-measured, so you don't need to adjust it yourself. You apply the cream inside the urethra using the applicator, and the medicine is absorbed through the urethral lining. Like Caverject, Vitaros should not be used more than once in 24 hours or more than three times a week.

Your prescriber will consider factors such as your comfort with injections, manual dexterity, and any urethral conditions when recommending a strength and method. Some men prefer the simplicity of a pre-measured applicator, while others find injections more reliable. Both methods require careful technique to work safely and effectively.

Can You Adjust the Dose Yourself?

With Caverject, dose adjustments are possible under medical supervision [7]. Your prescriber may increase or decrease the dose depending on how well it works and whether you experience side effects. Never adjust the dose yourself without guidance, as using too much can cause a prolonged erection. With Vitaros, the dose is fixed at 300 micrograms per applicator, so there's less flexibility. If the standard dose doesn't work well, your prescriber may suggest trying Caverject or switching to an oral treatment instead.

Side Effects: Caverject vs Vitaros

Caverject injections can cause pain or aching at the injection site, which is one of the most common side effects [7]. Some men also notice bruising, bleeding, or a small lump where the needle was inserted. Prolonged erection (priapism) is a rare but serious risk, especially if the dose is too high. Other possible side effects include dizziness, headache, and changes in blood pressure. If you have a history of blood clotting disorders or take anticoagulants, your prescriber will assess whether Caverject is safe for you.

Vitaros cream can cause a burning or stinging sensation in the urethra after application, which some men find uncomfortable [7]. This usually settles within a few minutes. Other side effects include urethral bleeding, dizziness, headache, and (rarely) prolonged erection. Because the cream is applied inside the urethra, it's not suitable if you have urethral stricture, severe curvature of the penis (Peyronie's disease), or a history of priapism.

Both treatments carry a small risk of passing alprostadil to a partner during sex, which can cause vaginal irritation or itching [7]. Using a condom can reduce this risk. If your partner is pregnant, you must use a condom, as alprostadil may affect the developing baby. Always report any unexpected or severe side effects to your prescriber or pharmacist.

Which Has Fewer Side Effects?

Neither treatment is clearly 'better' in terms of side effects—it depends on what you find more tolerable [7]. Some men prefer Vitaros because it avoids needles and injection-site pain, but the urethral burning can be off-putting. Others find Caverject more reliable despite the discomfort of injecting. Your prescriber will discuss your preferences and any conditions that might make one option safer than the other. Both treatments require careful technique and monitoring, especially when you first start.

When to get urgent help

• Erection lasting more than two hours (seek same-day help) or more than four hours (call 999)
• Sudden severe pain in the penis or signs of infection at the injection site
• Chest pain, severe dizziness, or fainting after using either treatment
• Sudden loss of vision or hearing
• Severe allergic reaction (swelling of face, lips, or throat; difficulty breathing)

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.

Who Might Suit Caverject vs Vitaros?

Caverject may suit men who are comfortable with self-injection and want a fast, predictable response [7]. It's often recommended if oral tablets haven't worked or aren't suitable—for example, if you take nitrates for angina (which cannot be combined with PDE5 inhibitors). Caverject can also be an option after prostate surgery or radiotherapy, when nerve damage affects the response to oral medicines. However, it's not suitable if you have conditions that increase the risk of priapism, such as sickle cell disease, leukaemia, or multiple myeloma.

Vitaros may be a better choice if you prefer to avoid injections or have difficulty with manual dexterity [7]. The pre-filled applicator is easier to use for some men, though the urethral application can feel uncomfortable at first. Vitaros is also prescription-only and requires training, but many men find it less invasive than an injection. It's not suitable if you have urethral abnormalities, severe penile curvature, or a partner who is pregnant (unless you use a condom).

Both treatments require an online consultation with a UK prescriber, who will review your medical history, current medicines, and any heart or blood vessel conditions. If you're taking alpha-blockers (such as tamsulosin or doxazosin), blood pressure medicines, or anticoagulants, your prescriber will check whether alprostadil is safe. Neither Caverject nor Vitaros interacts with nitrates in the same way PDE5 inhibitors do, but you must still declare all medicines and conditions during your consultation.

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