Alprostadil Injection: Uses, Dosage, Side Effects, Precautions and Alternates

Quick overview

Alprostadil Injection contains alprostadil, a synthetic prostaglandin E1 analog that works as a vasodilator by widening blood vessels. It is used mainly as a second-line treatment for erectile dysfunction, given by injection directly into the penis, and in a different form to keep a blood vessel open in newborns with certain congenital heart conditions. It is also used in combination products such as Trimix and in penile Doppler ultrasound testing.

What is Alprostadil Injection

Alprostadil is a man-made version of a natural body substance called prostaglandin E1. It works as a vasodilator, meaning it widens blood vessels by relaxing their walls. It is given by injection and is used mainly to treat erectile dysfunction, and in a different form to keep a blood vessel open in newborn babies with certain heart conditions.

Alprostadil Injection uses

• Second-line treatment for erectile dysfunction when oral tablets have not worked
• Injected directly into the penis (intracavernosal injection) to produce an erection
• Used in combination products such as Trimix (with papaverine and phentolamine) for erectile dysfunction
• In infants, given intravenously to temporarily keep a blood vessel (ductus arteriosus) open in certain congenital heart defects until surgery can be done
• Used in penile Doppler ultrasound tests to assess blood flow for erectile function

Benefits of Alprostadil Injection

• Helps produce an erection firm enough for sexual intercourse in a large proportion of men who use it
• Works when other treatments such as oral tablets have failed
• In newborns, helps keep a vital blood vessel open until surgery can be performed

How Alprostadil Injection works

Alprostadil relaxes the smooth muscle in blood vessel walls, causing them to widen. In the penis, this increases blood flow into the erectile tissue, producing an erection. In newborns, it relaxes the muscle in the wall of a temporary blood vessel (the ductus arteriosus) to keep it open until heart surgery can be done.

Alprostadil Injection dosage

The first injection should be given by a healthcare professional so you can be shown the correct technique. After the first supervised injection, you may be able to give yourself injections at home if you strictly follow your prescribed dosing schedule. Never increase your dose without your doctor's approval. Injections should not be given more than a few times per week, with at least 24 hours between doses. Seek immediate medical attention if an erection lasts longer than a few hours.

In infants, the medicine is given as a continuous infusion into a vein or through a small tube into the umbilical artery, by trained healthcare staff in a facility with intensive care available.

Available forms and strengths

• Injection (solution for intracavernosal or intravenous/intra-arterial use)
• Cream
• Urethral suppository (pellet)

Side effects of Alprostadil Injection

Common

• Pain, aching, or discomfort at the injection site
• Bruising or bleeding at the injection site
• Swelling of the penis
• Redness or skin discoloration at the injection site
• Headache
• Dizziness
• Flushing
• Feeling sick (nausea)
• Flu-like symptoms

Serious

• Priapism (a painful erection lasting longer than 4 hours)
• Penile fibrosis (scarring or hard knots in the penis)
• Abnormal curving or shape of the penis (Peyronie's disease)
• Severe allergic reaction (rash, itching, swelling, difficulty breathing)
• Low blood pressure, dizziness, or fainting
• Penile infection
• Priapism requiring emergency treatment to prevent permanent damage

Warnings and precautions

• Alprostadil can cause priapism, a painful and prolonged erection lasting longer than four hours, which needs urgent medical treatment.
• Long-term use for erectile dysfunction can cause penile fibrosis, where the penis becomes scarred, which may affect erectile function.
• Severe allergic reactions can occur, though this is rare.
• The medicine can cause a drop in blood pressure, which may lead to dizziness or fainting.
• It may increase the risk of bleeding, especially in people with bleeding disorders or those taking blood thinners.
• Do not combine alprostadil with other erectile dysfunction medications, as this increases the risk of serious side effects including very prolonged erections.
• You should not use alprostadil if you have been advised not to have sex, have a penile implant, are taking other erectile dysfunction medications, have a condition that increases risk of prolonged erection, or have severe curvature of the penis.
• Discuss use during pregnancy with your healthcare provider.
• Discuss use while breastfeeding with your healthcare provider.
• Tell your healthcare provider about any underlying kidney conditions, as special precautions or dose adjustments may be needed.
• Tell your healthcare provider about any underlying liver disease, as special precautions or dose adjustments may be needed.
• You can drink alcohol while using alprostadil injections, as no interaction has been found, though alcohol can worsen erectile dysfunction and reduce the medicine's effectiveness.
• Assess how this medicine affects you before you drive or operate machinery.

Storage

• Store in a refrigerator between 2°C and 8°C
• Prepare fresh diluted solution every 24 hours and discard any solution more than 24 hours old
• Keep out of reach and sight of children

When to see a doctor

• Go to the emergency room immediately if your erection lasts longer than 4 hours.
• Contact a healthcare provider right away if you develop a painful curve during an erection, swelling or pain in the testicles or legs, flu-like symptoms with fever or chills, dizziness or fainting, scarring or hard areas on the penis, or if the injection needle breaks or the solution looks cloudy or discolored.
• If priapism (a prolonged, painful erection) occurs, seek immediate medical attention, as it can permanently damage the penis if not treated promptly.
• Seek medical help if you experience rash, itching, swelling, severe dizziness, or difficulty breathing.

Alternatives

• Trimix
• Quadmix
• Double-strength Trimix
• Alprostadil cream (Vitaros)
• Intraurethral alprostadil suppositories (MUSE)