What Is Caverject? Uses, Dosage, and What You Need to Know in 2026

Caverject is a brand name for alprostadil, a medication injected directly into the penis to treat erectile dysfunction (ED). It has been available in the United States since 1981 and remains one of the most effective treatments for ED — particularly for men who don't respond to oral medications like Viagra or Cialis. In 2025, Pfizer discontinued the brand, but generic alprostadil injection remains available. Here's everything you need to know.

What Is Caverject Used For?

Caverject (alprostadil) is FDA-approved for two primary uses:

Treatment of erectile dysfunction: For men with ED due to vasculogenic (blood vessel-related), psychogenic (psychological), neurogenic (nerve-related), or mixed causes. It is typically prescribed after oral ED medications have failed or are contraindicated.

Diagnostic testing for ED: Alprostadil is sometimes used by urologists during penile vascular testing (e.g., penile duplex Doppler imaging) to evaluate blood flow and characterize the underlying cause of ED.

Alprostadil is the only FDA-approved agent for intracavernosal injection treatment of erectile dysfunction. In clinical studies, over 80% of men achieved an erection sufficient for intercourse with Caverject.

What Drug Class Is Caverject?

Caverject belongs to the class of drugs known as prostaglandins — specifically, it is a synthetic form of Prostaglandin E1 (PGE1). Prostaglandins are lipid compounds that occur naturally in the body and have diverse biological effects, including the relaxation of smooth muscle. In the case of alprostadil, this relaxation is targeted at the blood vessels and smooth muscle of the corpus cavernosum (the erectile tissue of the penis), increasing blood flow and producing an erection.

What Are the Available Forms and Doses?

Caverject was available in two main formulations:

Caverject (vials): Single-dose vials of 20 mcg or 40 mcg powder that must be reconstituted with bacteriostatic water before injection using a separate syringe and needle.

Caverject Impulse (prefilled syringe): A dual-chamber glass cartridge syringe available in 10 mcg and 20 mcg, where the alprostadil and diluent are pre-loaded and automatically mixed when activated. More convenient but more expensive than the vial form.

Since Pfizer discontinued the brand in July 2025, generic alprostadil injection (10 mcg and 20 mcg) is the current standard. Edex (by Endo) is another brand of alprostadil injection still available in doses of 10 mcg, 20 mcg, and 40 mcg.

How Is Caverject Dosed?

Dosing is highly individualized and must be determined through in-office titration. General guidelines:

Starting dose: 2.5 mcg for vasculogenic/psychogenic/mixed ED; 1.25 mcg for neurogenic ED (e.g., spinal cord injury)

Titration: Dose increased in increments of 2.5–10 mcg, at least 24 hours apart, until the lowest effective dose producing a suitable erection (not exceeding 1 hour) is found

Maximum dose: 60 mcg (Caverject/generic alprostadil); 40 mcg (Edex)

Frequency: No more than 3 times per week; at least 24 hours between doses

Onset: 5–20 minutes after injection

Duration: Up to 60 minutes (mean 67.5 minutes in clinical studies)

Is Caverject a Controlled Substance?

No. Alprostadil (Caverject) is not a controlled substance under the DEA scheduling system. It is a prescription-only medication, but prescriptions can be written by any licensed prescriber — urologists, PCPs, NPs, and PAs — without the DEA restrictions that apply to scheduled drugs. There are no refill limits based on controlled substance status.

Who Should Not Use Caverject?

Men with Peyronie's disease or penile deformity

Men with penile implants

Men with conditions predisposing to priapism (sickle cell anemia, multiple myeloma, leukemia)

Men for whom sexual activity is medically inadvisable due to cardiovascular risk

Men with known cavernosal venous leakage

Finding Caverject or Generic Alprostadil in 2026

With the Caverject brand discontinued, finding generic alprostadil injection locally requires some legwork. medfinder can help — enter your medication, dose, and zip code and medfinder will call pharmacies near you to find out which ones can fill your prescription.

Curious how it works? Read our article on how Caverject works: mechanism of action explained in plain English.