MUSE for Erectile Dysfunction: How It Works, What to Expect and Who It Suits

MUSE (Medicated Urethral System for Erection) is a small pellet of alprostadil inserted into the urethra using a thin applicator. It is a second-line treatment for erectile dysfunction. Doctors typically recommend it for men who have not responded to oral medicines like sildenafil or tadalafil, or who cannot take them safely. It holds MHRA approval in the UK.

How MUSE works#

Alprostadil is a prostaglandin (a naturally occurring compound that widens blood vessels). Once the pellet dissolves in the urethra, alprostadil is absorbed into the surrounding tissue. It relaxes the smooth muscle in the penile arteries, increases blood flow, and produces an erection.

Because it works locally rather than through the bloodstream, it does not require the same nerve signals that PDE5 inhibitors like sildenafil depend on. That is why it can work for men with nerve damage after prostate surgery.

Dosing and how to use it#

MUSE comes in four strengths: 125 mcg, 250 mcg, 500 mcg, and 1000 mcg. Your doctor or specialist nurse will usually start you at a lower dose and adjust based on your response. The dose is titrated in a clinic before you use it at home.

Step-by-step use:

1. Urinate before inserting the pellet. The moisture left in the urethra helps the pellet dissolve. After urinating, shake the penis gently to remove excess urine while keeping slight moisture.
2. Sit or stand. Stretch the penis gently upward to straighten the urethra.
3. Insert the applicator stem about 3 cm into the urethra.
4. Press the button at the top to release the pellet.
5. Hold for 5 seconds, then rock the applicator gently side to side before removing.
6. Roll the penis between your palms for 10 seconds to help distribute the medicine.

You should use MUSE no more than once per day. Your first dose should always be given in a clinical setting (urology or sexual health clinic) so that a healthcare professional can check your response and blood pressure.

How quickly does it work, and how long does the erection last?#

MUSE typically produces an erection within 5 to 10 minutes of insertion. The effect lasts around 30 to 60 minutes.

How effective is MUSE?#

The landmark 1997 trial published in the New England Journal of Medicine found that 65% of men achieved an erection sufficient for intercourse in a clinic setting, but only around 50% reported successful intercourse at home. Real-world data puts effective response rates closer to 30 to 50%, which is meaningfully lower than oral PDE5 inhibitors.

For comparison, sildenafil and tadalafil produce satisfactory erections in roughly 60 to 80% of men. MUSE is less effective and less convenient, but it remains a valuable option for men who cannot use oral medicines.

Side effects to know about#

Penile pain is the most common side effect. In clinical trials, around 30% of men reported mild penile pain, roughly 10% reported urethral burning, and a smaller number reported testicular ache. Most found the discomfort short-lived.

Less common but important effects include:

• Minor urethral bleeding
• Dizziness or light-headedness from a blood pressure drop
• Prolonged erection (priapism), which requires emergency medical attention if it lasts more than 2 hours

Avoid driving if you feel dizzy or light-headed after use. The dizziness is related to a drop in blood pressure and is not universal, so this is a symptom-dependent precaution rather than an absolute rule.

Partner effects: Alprostadil can be absorbed vaginally during intercourse. If your partner is pregnant, or is of childbearing potential (able to become pregnant), you should use a condom as a barrier method. Alprostadil carries a theoretical risk to a pregnancy through local absorption, so a condom is important in these situations. Your partner may also experience mild vaginal burning even when she is not pregnant, so discuss this with your prescriber.

Who MUSE is not suitable for#

MUSE is contraindicated in men with:

• Conditions that increase the risk of priapism (a sustained, painful erection), including sickle cell disease and leukaemia
• Severe penile anatomical abnormalities such as significant Peyronie's disease
• Known hypersensitivity to alprostadil

If you take anticoagulants, tell your prescriber before using MUSE. Because of the risk of urethral bleeding, your prescriber should review whether MUSE is suitable for you before you start. Do not begin using it without that review.

Nitrate medicines (such as GTN spray or isosorbide mononitrate) need particular care. MUSE is not listed as absolutely contraindicated with nitrates in the way PDE5 inhibitors are, but that does not mean it is safe to start on your own. Alprostadil can lower blood pressure, and the combination may increase that risk. If you take nitrates, do not use MUSE unless a specialist or prescribing clinician has assessed you first and confirmed it is appropriate.

MUSE versus other second-line options#

If oral PDE5 inhibitors have failed, you have three main alternatives.

Caverject delivers alprostadil by injection directly into the corpora cavernosa. Many men find the idea uncomfortable, but injection-related pain is generally mild. Injectable alprostadil tends to produce firmer erections than MUSE, though tolerance varies between individuals.

Getting MUSE in the UK#

MUSE is available on the NHS, but it is typically second-line and usually requires a referral to a urology or sexual dysfunction clinic. Your GP may refer you if your ED is related to a condition such as diabetes, or follows prostate surgery.

Privately, MUSE is expensive: typically £10 to £20 per dose. Because it needs dose titration and clinical supervision at first use, it is not available through standard online pharmacy consultations in the same way as oral tablets.

If you have not yet tried oral ED treatment, or want to explore whether one could work for you, Totiva's erectile dysfunction service offers a free online consultation with a UK-registered clinician covering options including sildenafil and tadalafil. You only pay if treatment is approved, and MUSE is not available through Totiva.

For more on how oral options compare, the Totiva guide to tadalafil dosage covers timing, strengths and what to expect in practical detail.