What it is
Active ingredient: Alprostadil · Dosage form on catalogue: Cream 3 mg/g, on demand
How it works
A copy of prostaglandin E1
Alprostadil is chemically identical to prostaglandin E1, a signalling substance the body already makes. It is not swallowed — it is placed into or onto the penis itself, so it acts on the erectile tissue at the site rather than circulating through the whole body first.
Cavernosal muscle relaxes
It relaxes the smooth muscle of the corpora cavernosa — the two spongy cylinders that run the length of the penis — and widens the cavernosal arteries feeding them. Blood flow into the erectile tissue rises, and that increase in flow is what produces rigidity.
EP and IP prostanoid receptors
Alprostadil activates EP and IP prostanoid receptors on the surface of corpus cavernosum smooth-muscle cells. Receptor activation increases intracellular cyclic AMP, which lowers cytosolic calcium and produces smooth-muscle relaxation independently of the nitric-oxide pathway targeted by PDE5 inhibitors (PMID 8596569).
EU authorisation
MUSE holds national authorisations rather than a centralised EU one. The details here come from the Spanish authorisation (AEMPS registrations 62696, 62697 and 62698, holder Viatris Healthcare Limited). All three Spanish strengths are recorded as authorised but not currently marketed, and MUSE no longer appears in the United Kingdom medicines compendium, so European availability is very limited.
What the studies reported
The evidence base for alprostadil spans its three delivery routes. The transurethral pivotal trial (MUSE Study Group, N Engl J Med 1997, PMID 8970933) was a double-blind, placebo-controlled study of 1,511 men aged 27 to 88 years with chronic erectile dysfunction from organic causes. Participants first received up to four in-clinic doses (125, 250, 500 and 1,000 mcg); those who responded were randomised to the effective dose or placebo for three months at home. During in-clinic testing, 65.9% achieved erections sufficient for intercourse; at home, 64.9% of those on alprostadil had intercourse successfully at least once versus 18.6% on placebo (P<0.001). The IIEF changes reported for the cream form are small in absolute terms, and the authors describe the SEP2 and SEP3 improvements as slight though statistically significant; those studies ran for 12 weeks and cover the topical cream only.What has been reported
Who it is not suitable for
MUSE is contraindicated in men with a hypersensitivity to alprostadil, with anatomical urethral abnormalities such as stricture or severe hypospadias, or with conditions that predispose to priapism such as sickle-cell disease, multiple myeloma or leukaemia. It should not be used in men for whom sexual activity is inadvisable because of cardiovascular risk, or in men with a penile implant. Because the Spanish strengths are recorded as authorised but not currently marketed, and MUSE is not listed in the UK medicines compendium, its European availability is very limited — the reviewing doctor considers whether it can be sourced and whether it is the appropriate route for you compared with the alprostadil cream or injection.How Hi Doctor handles it
A doctor reviews every sexual health option and recommends what fits your history and goals. If alprostadil is appropriate, they explain the chosen route and administration technique.Prescribed with clear administration instructions
If a doctor decides alprostadil is right for you, they explain how to use the pellet or the alternative route.
Related reading
- Alprostadil — the same active ingredient as a cream or injection
- Tadalafil (Cialis) — an oral alternative when tablets are suitable
- How a consultation works
- Safety and eligibility
Start a consultation
Sexual health consultation
Answer the sexual health questionnaire and a registered doctor reviews it.
They decide whether treatment is appropriate, which one, and at what dose —
and declining is a normal outcome. See what it costs
and how the review works.