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Priapism is a true urologic emergency. A persistent erection lasting more than four hours, unrelated to sexual stimulation, can cause permanent damage to penile tissue and lifelong erectile dysfunction if it is not treated promptly. The 2022 AUA/SMSNA priapism guideline treats it as a time-sensitive condition on par with testicular torsion: the longer it goes untreated, the worse the outcome. If this is happening now, stop reading and get help.
This is an emergency. If you have an erection that has lasted longer than four hours — especially if it is painful or unrelated to sexual arousal — go to the nearest emergency room now, or call 911. Do not wait to see if it resolves on its own. Irreversible tissue damage can begin within hours, and the chance of preserving normal erectile function drops sharply with every hour of delay. This article is educational and is not a substitute for emergency medical care.
When to Seek Emergency Care
Call 911 or go to the nearest emergency room if you have an erection lasting longer than four hours, particularly if it is painful or unconnected to sexual arousal. Do not attempt home remedies as a substitute for care, and do not “wait it out.” In ischemic priapism, smooth-muscle injury can begin within hours, and irreversible damage becomes the rule beyond about 24 hours. Emergency physicians and urologists can relieve the erection quickly when it is caught early; the delay is what causes lasting harm.
What Priapism Is
Priapism refers to a prolonged erection that is not the result of sexual desire and that lasts beyond the typical resolution period. There are three recognized subtypes, each with very different management implications.
Ischemic (low-flow) priapism is the most common — accounting for over 95% of cases — and is the dangerous one. It is a compartment syndrome of the penis: blood is trapped in the corpora cavernosa, oxygen tension drops, acidosis develops, and smooth muscle becomes ischemic. The erection is rigid and usually painful. Without treatment, fibrosis sets in and erectile dysfunction becomes likely. This is the form that makes priapism an emergency.
Non-ischemic (high-flow) priapism is far less common and is not a true emergency. It results from unregulated arterial inflow, usually after blunt perineal or genital trauma that creates a fistula between a cavernous artery and the corpora. The erection is typically partial and not painful. Even so, it still warrants urologic evaluation.
Stuttering (recurrent) priapism is a repeating pattern of brief ischemic episodes, often seen in sickle cell disease. Each prolonged episode is still an emergency, and the pattern itself needs preventive treatment.
What Causes Priapism
Sickle cell disease is the leading cause in younger men, particularly Black men; a large share of men with the disease experience ischemic or stuttering episodes over their lifetime. Other hematologic causes include leukemia, thalassemia, and hypercoagulable states. Drug-induced priapism accounts for a substantial fraction of adult cases: intracavernosal injection therapy for ED (alprostadil, “trimix”), trazodone, antipsychotics (especially chlorpromazine and risperidone), cocaine, methamphetamine, and, less often, PDE5 inhibitors — particularly when combined with injection therapy.
Less common contributors include perineal or pelvic trauma (most often non-ischemic), pelvic malignancy, spinal cord injury, total parenteral nutrition with fat emulsions, and idiopathic cases where no cause is found. The Cleveland Clinic notes that drug-induced and sickle-cell-related episodes are the two largest US categories.
Symptoms and Red Flags
The hallmark is an erection lasting beyond four hours without sexual arousal. Ischemic priapism is rigid, often increasingly painful over hours, and typically the glans is soft while the shaft is hard. Non-ischemic priapism is partial, painless, and often appears days after a perineal injury.
Any erection over four hours warrants emergency evaluation. At six hours and beyond, the urgency escalates further. Beyond 24 hours, irreversible erectile dysfunction is the rule rather than the exception in untreated ischemic priapism. When in doubt, treat it as an emergency and be seen — a clinician can quickly distinguish the ischemic from the non-ischemic form.
Emergency Diagnosis
Diagnosis happens in parallel with treatment; workup should not delay relieving an ischemic erection. The ER physician or urologist obtains a focused history (timing, sickle cell status, drug exposure, trauma, ED injection use), performs a physical exam, and aspirates corporal blood for blood-gas analysis. Ischemic priapism shows acidotic, hypoxic dark blood (pH under about 7.25, pO2 under about 30 mmHg). Non-ischemic priapism shows oxygenated, bright red blood and is often confirmed with penile color Doppler ultrasound. CT or MRI may be used in trauma cases to identify a fistula.
Treatment
For acute ischemic priapism, the 2022 AUA/SMSNA guideline makes intracavernosal phenylephrine combined with corporal aspiration (with or without saline irrigation) the first-line treatment, performed before operative options. Phenylephrine is the agent of choice because of its selective alpha-1 activity and relatively limited cardiovascular effect; blood pressure and heart rate are monitored during injection. Injections may be repeated at short intervals as needed, and success rates are high when treatment starts early and fall as the episode lengthens. Importantly, the guideline states that conservative measures alone — observation, oral medications, cold compresses, or exercise — are unlikely to work in established ischemic priapism and should not delay definitive therapy.
If aspiration and phenylephrine fail, surgical shunting is the next step — distal shunts (Winter, Ebbehoj, Al-Ghorab) are tried first, with proximal shunts reserved for refractory cases. Early penile implant placement is increasingly considered for refractory priapism beyond roughly 36 to 48 hours, because fibrosis makes later implantation extremely difficult and erectile dysfunction is essentially guaranteed at that point.
Sickle cell priapism additionally requires attention to the underlying disease — hydration, oxygenation, pain control, and, in severe cases, consideration of transfusion — but this systemic care should not delay local treatment of the erection itself. Stuttering priapism is managed over the long term with agents that may include PDE5 inhibitors, oral alpha-agonists, hormonal therapy, and hydroxyurea; newer sickle-cell therapies such as crizanlizumab and voxelotor are being studied for their effect on priapism but are not established priapism treatments and should be directed by a hematologist. Non-ischemic priapism is generally managed with watchful waiting or selective arterial embolization, and immediate intervention is rarely needed.
Prevention
Men using intracavernosal injection therapy should follow strict dose limits and have a written action plan for a prolonged erection. Men with sickle cell disease should be educated on early warning signs and have access to urgent care and hematology follow-up. Avoiding combinations of vasoactive ED drugs, recreational stimulants, and trazodone reduces drug-induced episodes. For broader context on related sexual-function issues, see erectile dysfunction and ED medications compared.
When to See a Doctor
Any erection lasting longer than four hours requires emergency evaluation, full stop — go to the ER or call 911. Recurrent brief erections lasting one to three hours (stuttering priapism) require urgent outpatient urologic evaluation, particularly in men with sickle cell disease, so that preventive therapy can begin. After-effects of an episode — pain, fibrosis, or erectile dysfunction — should be evaluated by a urologist within days to weeks of the acute event.
For ongoing care of related conditions, see our medical conditions hub.
Frequently Asked Questions
Can priapism cause permanent damage?
Yes. Ischemic priapism lasting more than about 24 hours typically causes fibrosis of the corporal smooth muscle and irreversible erectile dysfunction. Injury can begin within hours and accelerates the longer the erection persists. That is why immediate treatment matters so much — it is the single biggest factor in whether function is preserved.
Is priapism caused by Viagra or Cialis?
Priapism from oral PDE5 inhibitors alone is rare. Risk increases when these drugs are combined with intracavernosal injections, recreational stimulants, or in men with sickle cell disease. The far more common iatrogenic cause is intracavernosal injection therapy for ED. If a prolonged erection occurs after any of these, treat it as an emergency.
What should I do while heading to the ER?
The priority is getting to emergency care quickly — nothing you do at home reliably reverses ischemic priapism. Some clinicians suggest measures such as hydration, or, for sickle-cell-related episodes, light activity, but these must never delay the trip to the hospital. Do not use additional ED medication, and do not attempt to “work it off.” Go now.
Can priapism happen more than once?
Yes — particularly in men with sickle cell disease (stuttering priapism) and in men using injection therapy. Recurrence is a sign that long-term preventive therapy, guided by a urologist and, where relevant, a hematologist, is needed.
Is non-ischemic priapism also an emergency?
It is less urgent than ischemic priapism because the tissue is still getting oxygenated blood, and it is often painless. However, you usually cannot tell the two forms apart on your own, so any erection over four hours should be evaluated urgently. A clinician confirms the type with a blood-gas sample and ultrasound.
The Bottom Line
Priapism is one of the few sexual-medicine conditions that is unambiguously a 911 issue. The window for full recovery is measured in hours, not days. Anyone with a non-stop erection beyond four hours — especially a painful one — should head directly to an emergency department. With prompt aspiration and intracavernosal phenylephrine, most men recover normal function; delay is what turns a treatable problem into a permanent one. If you are unsure whether it counts, err on the side of being seen — go to the ER.