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Alprostadil is a copy of prostaglandin E1, a substance the body makes naturally that widens blood vessels. Caverject is the intracavernosal injection form — it is not swallowed, but injected into the side of the penis, so it acts on the blood vessels directly rather than circulating through the whole body first.

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What it is

Active ingredient

Alprostadil, chemically identical to prostaglandin E1.

Route

Injection directly into the side of the penis (intracavernosal).
Caverject holds national authorisations rather than a centralised EU one; the details on this page come from the Spanish authorisation (AEMPS registrations 60535 and 60911, holder Pfizer, S.L.), where both strengths are currently marketed. In the United Kingdom, Pfizer Limited also holds a Caverject Dual Chamber presentation at 10 and 20 micrograms. It has been authorised for use in the EU since 29 November 1994, so a licensed doctor can prescribe it when clinically appropriate.
Because it is injected, the first dose is normally given and taught in a clinical setting.

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How it works

A copy of prostaglandin E1

Alprostadil is placed into 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 produces rigidity.

It does not need arousal

Because it acts directly on the blood vessels, it does not depend on the signalling pathway used by PDE5 tablets such as sildenafil or tadalafil.

A non-PDE5 route

A different pathway from oral erectile dysfunction tablets.

Direct, local action

Acts on the blood vessels at the site, not system-wide.

An option when tablets don't work

Considered when oral PDE5 tablets aren’t the right fit or aren’t allowed.

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What the studies reported

Efficacy and safety data for intracavernosal alprostadil were reported in N Engl J Med 1996 (PMID 8596569), including a six-month self-injection study. Every NCT identifier in Hi-Doctor’s evidence base links to its ClinicalTrials.gov record; a readout is not the same as peer-reviewed publication.

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What has been reported

An erection lasting 4 hours or more is priapism, and it is a medical emergency. Untreated priapism can permanently damage erectile tissue.

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Who it is not suitable for

A doctor assesses history and current medication before prescribing, and decides whether Caverject or another sexual health option is appropriate. Men with a history of priapism, Peyronie’s disease, or who are taking anticoagulants or antiplatelet medicines need a careful evaluation. For men who prefer a cream applied to the tip of the penis rather than an injection, Vitaros is the alprostadil cream form, reviewed separately.
Because it is injected, the first dose is normally given and taught in a clinical setting. The reviewing doctor decides case by case — nothing here is prescribed without evaluation.

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Common questions

An erection typically lasts between 30 and 60 minutes. If it lasts 4 hours or more, seek urgent medical attention — untreated priapism can permanently damage erectile tissue.
Yes. Caverject acts through a different pathway from PDE5 inhibitor tablets such as sildenafil or tadalafil, so it is considered when oral tablets are not the right fit or are not allowed.
Because it acts directly on the blood vessels in the penis, it does not depend on the signalling pathway used by PDE5 tablets. It does not need arousal, but sexual stimulation naturally complements the effect.
Both contain alprostadil. Caverject is injected into the side of the penis (intracavernosal). Vitaros is a cream applied to the tip of the penis. Both act locally on the blood vessels rather than circulating through the whole body first.
The questionnaire covers symptoms, cardiovascular history, current medication and allergies. A registered doctor reviews the case personally and decides whether Caverject or another option is appropriate.

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How Hi-Doctor handles it

The questionnaire covers symptoms, cardiovascular history, current medication and allergies — see how eligibility works. Certain answers, such as nitrate medication, rule treatment out entirely because of a dangerous interaction; see safety for how these checks run. Caverject is one of several sexual health options a doctor may consider. The consultation cost is set out on pricing; the medicine itself is paid separately at a pharmacy.

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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.
This page is reference information, not medical advice and not a prescription. Whether a medicine is appropriate for you is decided by a registered doctor after reviewing your consultation.