Why would someone use this instead of a tablet?

Because the tablets rely on a nerve signal that is absent or too weak in some people, particularly after certain prostate operations. Alprostadil acts on the blood vessels directly, so it does not depend on that signal.

Is the injection self-administered?

After training, yes, and the label describes the technique. The first administration is normally supervised by a clinician.

What is a prolonged erection warning?

The label carries a warning about erections lasting beyond a stated number of hours, which is a medical emergency because the blood in the penis stops being oxygenated. The threshold and the instruction are in the label section on this page.

Alprostadil

The option for people the tablets do not work for, given as a pellet into the urethra or an injection rather than swallowed.

Class: Prostaglandin E1
Sold as: Sold as: Muse, Caverject, Vitaros; Prescription only

From the approved label

Muse

Approved uses: GLIADEL Wafer is an alkylating drug indicated for the treatment of: newly-diagnosed high-grade glioma as an adjunct to surgery and radiation and recurrent glioblastoma as an adjunct to surgery
Forms and strengths: GLIADEL Wafer is an off-white to pale yellow round wafer.
Each GLIADEL Wafer contains 7.7 mg of carmustine.
How it is taken: Recommended dose: Eight 7.7 mg wafers (61.6 mg total dose) implanted intracranially
Follow preparation and handling recommendations.
Must not be used when: None. The label states that there are no contraindications.
Warnings and precautions: Seizures: Monitor patients for seizures following implantation.
Intracranial hypertension: Monitor patients for signs of increased intracranial pressure.
Impaired neurosurgical wound healing: Monitor patients for complications of craniotomy.
Meningitis: Monitor patients for signs of bacterial or chemical meningitis.
Common side effects: Most common adverse reactions (incidence >10% and between arm difference ≥4%) are cerebral edema, asthenia, nausea, vomiting, constipation, wound healing abnormalities and depression.
Pregnancy: GLIADEL Wafer can cause fetal harm when administered to a pregnant woman. There are no available data on GLIADEL use in pregnant women. There have been no animal reproductive studies with GLIADEL Wafer; however, carmustine, the active component of GLIADEL Wafer, is embryotoxic and teratogenic in rats at exposures less than the exposure at the recommended human dose based on body surface area (BSA) and embryotoxic in rabbits at exposures similar to exposures at the...
How it acts: The activity of GLIADEL Wafer is due to release of cytotoxic concentrations of carmustine, a DNA and RNA alkylating agent, into the tumor resection cavity. On exposure to the aqueous environment of the resection cavity, the anhydride bonds in the copolymer are hydrolyzed, releasing carmustine, carboxyphenoxypropane, and sebacic acid into the surrounding brain tissue.

Label holder:: Azurity Pharmaceuticals, Inc.
Label version:: 5 December 2024

This section reports the approved product information. The wording is condensed from the regulator's own summary, and the full document is linked under Sources.

Written by us

How it works

Alprostadil is not a PDE5 inhibitor and does not depend on the nerve signal those drugs extend. It relaxes the blood vessels of the penis directly, which is why it can work when the tablets do not, including after prostate surgery where the nerves involved have been damaged. Delivering it means either a small pellet placed in the urethra or an injection into the side of the penis, both of which are taught by a clinician the first time.

Original and generic

The brands differ by delivery method rather than by substance: a urethral pellet, an injection, and in some European countries a cream. Generic versions of the injection exist. This is not a category where a cheaper equivalent tablet is available, because there is no tablet.

What it costs

More expensive per use than any of the tablets, and in several European health systems it is reimbursed for specific indications such as after prostate surgery, which changes the arithmetic considerably. Pricing outside reimbursement varies too much between countries to summarise usefully.

How to get it legally

Prescription only, and this is the one option in the category where an in-person appointment is genuinely the norm rather than a formality: the first dose is usually given under supervision so the technique and the response can be observed. Online clinics do not typically start treatment with it.

Questions

Why would someone use this instead of a tablet?: Because the tablets rely on a nerve signal that is absent or too weak in some people, particularly after certain prostate operations. Alprostadil acts on the blood vessels directly, so it does not depend on that signal.
Is the injection self-administered?: After training, yes, and the label describes the technique. The first administration is normally supervised by a clinician.
What is a prolonged erection warning?: The label carries a warning about erections lasting beyond a stated number of hours, which is a medical emergency because the blood in the penis stops being oxygenated. The threshold and the instruction are in the label section on this page.

Sources

Gliadel: prescribing informationDailyMed, US National Library of Medicine. Label version 5 December 2024
Drugs@FDA: NDA020637US Food and Drug Administration