Alprostadil urogenital: ED treatment, dosing, and side effects
Last updated September 7, 2026.
**Alprostadil urogenital is a prostaglandin E1 medicine placed directly into the penis, either as a urethral suppository or as an injection, to produce an erection.** It relaxes the smooth muscle and widens the arteries inside the erectile tissue, so blood flows in and is held there long enough for sex. It works on the penis itself rather than through sexual desire, so an erection can start within 5 to 10 minutes of a dose whether or not you feel aroused. The one point that matters most: if an erection lasts longer than 4 hours, you need medical care right away, because trapped blood can permanently damage the tissue.
What does it treat?
Alprostadil urogenital is used for erectile dysfunction in adult men, meaning trouble getting or keeping an erection firm enough for sex. Doctors reach for it most often when the cause is blood flow related (diabetes, high blood pressure, atherosclerosis, side effects of prostate surgery) or nerve related (spinal cord injury, pelvic nerve damage), and especially when pills such as sildenafil or tadalafil have not worked, are not tolerated, or cannot be used because you take nitrates. Because it acts on the tissue directly, it often still works when nerve signaling is impaired. You will see it as the urethral suppository MUSE and as the injections Caverject, Caverject Impulse, and Edex. It is also used at a low dose during penile ultrasound testing to see how well the arteries fill. There are no combination products; some men use it alongside a vacuum device or a constriction ring under a doctor's guidance.
How do you take it?
Alprostadil urogenital comes as a urethral suppository in 125, 250, 500, and 1000 mcg strengths and as a powder for injection into the side of the penis. Your first dose is given in a clinic so a clinician can watch the response and teach the technique. For the urethral suppository, many men start at 125 or 250 mcg, urinate first so the urethra is moist, insert the applicator about an inch, and roll the penis to spread the medicine; use no more than 2 doses in 24 hours and no more than 7 doses in a week. For injection, Caverject usually starts at 2.5 mcg (1.25 mcg if the cause is nerve related) and is raised in small steps to the lowest dose giving an erection of about an hour, with a ceiling of 60 mcg per dose for Caverject and 40 mcg for Edex; inject no more than 3 times a week and leave at least 24 hours between doses. Food and alcohol timing do not change how it works, and there is no missed dose to make up because you use it only when you plan to have sex. Stop and call your doctor if an erection goes past 4 hours, if pain does not settle after the erection ends, if you feel a new lump or bend in the penis, or if the dose stops working.
Side effects to know
- Common: Penile pain or burning is the most common effect and is reported by about a third of men using the urethral suppository, along with urethral burning or light spotting of blood, testicular ache, leg or groin aching, lightheadedness, and, with injections, bruising or a small firm spot where the needle went in.
- Serious: An erection lasting more than 4 hours, called priapism, needs emergency treatment because it can scar the erectile tissue and cause lasting loss of function. Get help right away for fainting or near fainting from a sudden drop in blood pressure, heavy or continuing bleeding from the urethra, or signs of an allergic reaction such as hives, swelling of the face or throat, or trouble breathing.
Who should not take it?
Do not use alprostadil urogenital if you have had an allergic reaction to it, if you have a penile implant, or if you have a condition that makes a stuck erection more likely, including sickle cell disease or trait, multiple myeloma, leukemia, polycythemia, or thrombocythemia. It is also not for you if the penis is anatomically abnormal in ways that block safe use, such as severe hypospadias, marked curvature, cavernosal fibrosis, or Peyronie's disease, and the urethral form is not used with urethral stricture, urethritis, or balanitis. Talk to your doctor first if a heart or lung problem makes sex itself risky, if you take blood thinners such as warfarin or apixaban (higher bleeding risk with injections), or if you take blood pressure medicines, alpha blockers, nitrates, or other vasodilators, since alprostadil can add to a drop in blood pressure and make you dizzy. Do not combine it with sildenafil, tadalafil, or another erection pill unless your doctor tells you to, because the combination raises the risk of a prolonged erection and low blood pressure. This medicine is for adult men only and is not used in women or children; if your partner is pregnant or could become pregnant, use a condom, because the effect of alprostadil on a pregnancy is not established. Alcohol does not interact directly, but heavy drinking blunts erections and adds to lightheadedness after a dose.
When is it an emergency?
Go to an emergency department or call 911 if an erection lasts more than 4 hours, if it becomes rigid and painful and will not go down, if you collapse or faint, or if you have chest pain or trouble breathing during or after sex. Call 911 as well for signs of a severe allergic reaction such as swelling of the lips, tongue, or throat, widespread hives, or wheezing. If too much was inserted or injected, or if a child or anyone else was exposed to the medicine, call Poison Control at 1-800-222-1222 right away; the main signs of too much are a prolonged erection, low blood pressure, dizziness, sweating, and fainting. Heavy bleeding from the urethra or the injection site that does not stop with several minutes of firm pressure also needs same day care.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
What is the maximum dose I can use?
For the urethral suppository, the highest single strength is 1000 mcg, and you should not use more than 2 doses in any 24 hour period or more than 7 doses in a week. For injection, the ceiling is 60 mcg per dose with Caverject and 40 mcg per dose with Edex, used no more than 3 times a week with at least 24 hours between doses. Most men do well far below those ceilings, because the goal is the lowest dose that gives an erection lasting about an hour. Using more than the label allows does not improve results and mainly raises your risk of a prolonged erection. If your usual dose has stopped working, ask your doctor rather than doubling up on your own.
Can I drink alcohol while using alprostadil?
There is no direct interaction between alcohol and alprostadil, so a drink or two will not neutralize the medicine. That said, alcohol itself reduces erectile response and can undo what the dose is doing. It also lowers blood pressure, which adds to the lightheadedness some men feel in the first several minutes after a dose. If you get dizzy after using it, keep alcohol out of the picture that evening and sit or lie down until the feeling passes.
Is it safe if my partner is pregnant?
Alprostadil urogenital is a men's medicine and is not used in women or children, but the drug can be transferred to a partner during sex. If your partner is pregnant, the label says to use a condom barrier, because the effect on a pregnancy has not been established. Partners who are not pregnant sometimes report vaginal burning or itching after exposure, which a condom also prevents. If your partner is pregnant or trying to conceive, raise it with your doctor before your next dose so you get a clear plan.
Do I need to take it with food?
No. Food does not affect how alprostadil urogenital works, because the medicine goes into the penile tissue rather than through your stomach. You do not need to time a dose around meals. One step does matter with the urethral suppository: urinate right before inserting it, since a moist urethra helps the pellet dissolve and lowers burning. After inserting or injecting, stand or walk for about 10 minutes to help the medicine absorb.
What are the signs I used too much?
The clearest sign is an erection that keeps going well past an hour and turns rigid and painful. Too much can also drop your blood pressure, causing dizziness, sweating, pallor, or fainting when you stand up. Some men notice a pounding heartbeat or leg weakness. If an erection passes 4 hours, go to an emergency department; treatment there can usually reverse it and protect the tissue. For any other overdose concern, call Poison Control at 1-800-222-1222.
What medicines interact with it?
Blood thinners such as warfarin, apixaban, or clopidogrel raise your risk of bruising and bleeding at the injection site or from the urethra. Blood pressure medicines, alpha blockers, nitrates, and other vasodilators can stack with alprostadil to drop your blood pressure and make you lightheaded. Do not combine it with sildenafil, tadalafil, vardenafil, or avanafil unless your doctor specifically sets that up, since the pair raises the risk of a prolonged erection and low blood pressure. Decongestants and other sympathomimetics may work against the erection. Bring your full medicine list, including supplements, to the visit where your dose is set.