Caverject (Alprostadil Injection)
Caverject is a brand of alprostadil for intracavernosal injection in erectile dysfunction. It produces reliable erection within 5–20 minutes and is used when oral PDE5 inhibitors are ineffective, contraindicated or insufficient — including post-prostatectomy and severe vascular ED.
- Active ingredients
- Alprostadil
- Manufacturer
- Pfizer
- Dosage forms
- injection
- Available dosages
- 10mcg, 20mcg, 40mcg
- Category
- Erectile Dysfunction (ED)
What is it?
Caverject is the brand name under which Pfizer (originally Upjohn) markets alprostadil (synthetic prostaglandin E1) for intracavernosal injection. FDA-approved in 1995, it is the first and most widely used intracavernosal pharmacological treatment for erectile dysfunction, and is on the WHO Essential Medicines List for ED. Edex is a parallel brand of alprostadil injection from Endo Pharmaceuticals; Muse is the urethral pellet form of the same molecule. Authorised generic alprostadil injection is also available.
Active ingredients
Each Caverject vial contains 10, 20 or 40 micrograms of alprostadil for reconstitution. The active substance is identical between branded Caverject, Edex and authorised generic alprostadil injection products, with bioequivalence required by the regulator. The Impulse pre-filled dual-chamber system simplifies preparation but contains the same active drug at the same strengths.
Forms and dosages
Caverject is supplied as 10, 20 and 40mcg vials for reconstitution and injection. Treatment starts with a low test dose (1.25–2.5mcg) administered by the prescriber to determine response and rule out priapism, then titrated to an effective dose typically in the 10–40mcg range. Patients are trained in self-injection technique. The dose is administered 5–20 minutes before sexual activity and should not exceed three doses per week or one per 24 hours.
Indications
Caverject is approved for erectile dysfunction of vasculogenic, neurogenic, psychogenic or mixed aetiology in adult men. It is widely used after prostatectomy for penile rehabilitation, in patients who fail or cannot use PDE5 inhibitors, and in those with cardiovascular contraindications to oral therapy. According to current ED guidelines, Caverject is second-line after oral PDE5 inhibitors but first-line in selected populations.
How it works
Alprostadil binds prostaglandin E receptors on smooth muscle of the corpus cavernosum, triggering cAMP-mediated relaxation of cavernosal smooth muscle independent of the nitric oxide pathway used by PDE5 inhibitors. This produces direct vasodilation in the corpora cavernosa with reliable engorgement within 5–20 minutes. Because the mechanism does not require sexual stimulation or intact NO pathways, Caverject works in many patients who do not respond to oral PDE5 inhibitors.
Frequently asked questions
When is Caverject used instead of pills like Viagra or Cialis? ▾
Caverject is used when oral PDE5 inhibitors are ineffective (some patients with diabetes, severe vascular disease, or after prostatectomy), contraindicated (concurrent nitrates, severe cardiovascular disease) or insufficient. According to current ED guidelines, oral PDE5 inhibitors are first-line for most men, with Caverject reserved for non-responders or those with contraindications.
Is Caverject difficult to self-inject? ▾
The technique requires training and the first dose is administered in clinic. Most patients become comfortable with self-injection within a few attempts. The needle is fine and the injection is into the side of the penis, not the head — discomfort is usually mild. According to the prescribing information, patients should not start self-injection until they have been trained and have successfully demonstrated the technique.
What should I do if an erection lasts too long after Caverject? ▾
Erections lasting more than 4 hours (priapism) require urgent medical attention because prolonged engorgement can damage cavernosal tissue. According to the prescribing information, patients are counselled in advance to seek emergency care if an erection exceeds 4 hours. Priapism is rare with correctly dosed Caverject but is the most serious adverse event.
How does Caverject compare with the urethral pellet (Muse)? ▾
Both contain alprostadil, but Caverject is injected into the side of the penis while Muse is inserted as a small pellet into the urethra. Caverject is more effective and reliable but requires comfort with injection technique; Muse avoids needles but is less reliable and often less effective. According to clinical practice, choice is based on effectiveness needs and patient preference.
Is Caverject the same as generic alprostadil injection? ▾
Yes — Caverject and authorised generic alprostadil injection products contain the same active ingredient at the same strengths and have demonstrated bioequivalence. Edex is a parallel branded product. The generic is significantly cheaper and clinically equivalent in nearly all cases. Most current prescribing is on the generic where available.
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The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.