Alprostadil for Erectile Dysfunction

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026

Quick Answer

Alprostadil is a prescription medication identical to a natural substance in the body that keeps blood vessels open [1]. It treats erectile dysfunction by increasing blood flow to the penis through an injection or a urethral suppository [1]. Injections work for about 80% of men and the suppository somewhat less often, but it must be used carefully to avoid prolonged erections [1].

What the research says

• Injected alprostadil allowed sexual activity after 94% of injections in a large self-injection study. In a six-month study of 683 men with erectile dysfunction, participants reported being able to have sexual activity after 94 percent of injections, and the men and their partners rated it satisfactory after 87 and 86 percent of injections. Penile pain occurred in 50 percent of men at some point (but after only 11 percent of injections), prolonged erections in 5 percent, priapism in 1 percent, penile fibrotic complications in 2 percent, and hematoma or bruising in 8 percent (PubMed: Linet & Ogrinc, N Engl J Med, 1996) [2].

• The transurethral suppository produced a full erection in about 7 in 10 men with organic ED in a placebo-controlled trial. In a double-blind study of 234 men with complete organic erectile dysfunction, 165 men (70.5%) achieved full penile enlargement or rigidity after at least one active dose. The best alprostadil dose (500 µg) did so in 51.8% of administrations versus 2.7% for placebo (p < 0.001), and the most common side effect was penile pain (PubMed: Peterson et al., J Urol, 1998) [3].

• At home, the suppository led to intercourse far more often than placebo. In a trial of 249 men, 159 (64%) had an erection sufficient for intercourse in the clinic. In the at-home phase, 69% of men on alprostadil (46 of 67) reported intercourse at least once versus 11% on placebo (8 of 73; p < 0.001), and 14% of patients reported urogenital pain (PubMed: Williams et al., Br J Urol, 1998) [4].

What is alprostadil for erectile dysfunction?

Alprostadil is a specialized medical treatment classified as a vasodilator [1]. Its primary function is to treat erectile dysfunction (ED) by widening the arteries and relaxing the smooth muscle tissue within the penis. This process allows for significantly increased blood flow, which is essential for achieving a firm erection. Alprostadil is chemically identical to a naturally occurring prostaglandin in the human body, making it a biocompatible option for those whose bodies do not produce enough of the substance to maintain vascular health.

Healthcare providers typically recommend alprostadil when first-line oral treatments, such as phosphodiesterase type 5 (PDE5) inhibitors, do not provide the desired results or lead to adverse reactions [1]. It is important to note that alprostadil is not a permanent cure for ED but rather a safe and effective long-term management tool [1].

Administration Methods

There are two primary ways that alprostadil is administered, each with its own set of characteristics regarding effectiveness and onset time.

Feature	Injectable Alprostadil	Transurethral Alprostadil
Method	Injection into the side of the penis [1]	Suppository inserted into the urethra [1]
Onset Time	5 to 20 minutes [1]	Within 10 minutes [1]
Effectiveness	Highly effective (~80% success) [1]	Generally less effective [1]
Common Issues	Bruising [1] [2], injection site pain	Penile pain, burning sensation [1]

How should alprostadil be used safely?

Strict adherence to usage instructions is critical to ensuring both the effectiveness of the medication and the safety of the user. Improper use or exceeding the recommended dosage can lead to permanent tissue damage [1].

1. Injectable Use: Should be used no more than two to three times per week, with at least 24 hours between each application [1].

2. Transurethral Use: Should not be used more than twice within a 24-hour period [1].

3. Duration: The resulting erection typically lasts between 30 and 60 minutes [1]. It may continue after climax but should naturally subside within an hour.

Contraindications and Precautions

Before starting alprostadil, it is essential to consult with a healthcare professional to review your medical history. Certain conditions may make the medication unsafe to use.

• Oral Medications: Alprostadil should never be combined with oral ED medications like Viagra [1], as this significantly increases the risk of toxic effects and prolonged erections.

• Pre-existing Conditions: Individuals with a history of priapism (long-lasting erections), Peyronie’s disease (penile curvature), or blood disorders like sickle cell anemia or leukemia [1] should exercise extreme caution.

• Penile Implants: The presence of a penile implant may affect how alprostadil is administered or its overall safety.

What are the potential risks and complications of alprostadil?

Complications from alprostadil are not common, but users should be aware of potential side effects. These can range from localized reactions to systemic issues like changes in blood pressure [1].

Injectable alprostadil may cause localized swelling, bruising, or a minor rash [1]. In rare cases, a penile infection may occur [1] if proper hygiene is not maintained during injection. Transurethral administration is more often linked to urethral pain or burning, minor urethral bleeding, and feelings of lightheadedness or fainting. The most significant risk associated with both forms is priapism—an erection that lasts longer than four hours. This is a medical emergency that requires immediate intervention at an emergency room [1] to prevent permanent scarring and loss of function.

Conclusion

Alprostadil remains a cornerstone in the treatment of erectile dysfunction, offering a reliable solution for many who have not found success with other therapies. By understanding the different administration methods and strictly following safety protocols, users can safely manage ED and improve their quality of life. Awareness of the warning signs for complications ensures that any risks are addressed promptly, maintaining the long-term health and functionality of the vascular system.

Frequently Asked Questions

1. Is alprostadil a cure for erectile dysfunction?

No, alprostadil is a treatment that helps manage symptoms of ED, but it does not address the underlying cause or provide a permanent cure.

2. How long does an erection from alprostadil last?

An erection typically lasts between 30 and 60 minutes. If it lasts longer than two hours, you should contact your doctor.

3. Can I use alprostadil if I don't have erectile dysfunction?

No, alprostadil should only be used as prescribed for the treatment of ED. Using it without a medical need can cause permanent damage.

4. What should I do if the needle breaks during injection?

Contact your healthcare provider immediately to ensure the fragment is safely removed and to prevent infection or injury.

5. Is there a topical cream version of alprostadil?

While topical creams and gels exist, they are not currently FDA-approved or available in the United States.

6. Can I take alprostadil with Viagra?

No, combining alprostadil with oral ED medications is unsafe and increases the risk of serious complications like priapism.

7. How often can I use the injectable form?

You should use injectable alprostadil no more than three times per week, ensuring at least 24 hours between each use.

8. Does alprostadil cause pain?

Some users experience minor pain or a burning sensation, particularly with the transurethral suppository form.

9. What is priapism?

Priapism is a prolonged, often painful erection lasting more than four hours. It is a medical emergency that requires immediate ER treatment.

10. How effective is alprostadil compared to pills?

Alprostadil has a success rate of approximately 80% and is often effective for individuals who do not respond to oral ED pills.

Related Reading

Penile Implant: Types, Surgery, Recovery and Results explains penile implants for erectile dysfunction.

References

1. Cleveland Clinic. Alprostadil: Types, Uses & Side Effects. Cleveland Clinic. Jul. 31, 2023. https://my.clevelandclinic.org/health/treatments/10051-alprostadil

2. Linet OI, Ogrinc FG. Efficacy and safety of intracavernosal alprostadil in men with erectile dysfunction. The Alprostadil Study Group. N Engl J Med. 1996;334(14):873-877. PMID 8596569. https://doi.org/10.1056/NEJM199604043341401

3. Peterson CA, Bennett AH, Hellstrom WJ, et al. Erectile response to transurethral alprostadil, prazosin and alprostadil-prazosin combinations. J Urol. 1998;159(5):1523-1527. PMID 9554347. https://doi.org/10.1097/00005392-199805000-00030

4. Williams G, Abbou CC, Amar ET, et al. The effect of transurethral alprostadil on the quality of life of men with erectile dysfunction, and their partners. MUSE Study Group. Br J Urol. 1998;82(6):847-854. PMID 9883223. https://doi.org/10.1046/j.1464-410x.1998.00937.x

Medical Disclaimer

This article is for informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read here.