Merck Manual

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Geetha Maddukuri

, MD, Saint Louis University

Reviewed/Revised Dec 2022
Topic Resources

Priapism is painful, persistent, abnormal erection unaccompanied by sexual desire or excitation. It is most common in boys aged 5 to 10 years and in men aged 20 to 50 years.

Pathophysiology of Priapism

The penis is composed of 3 corporeal bodies: 2 corpora cavernosa and 1 corpus spongiosum. Erection is the result of smooth muscle relaxation and increased arterial flow into the corpora cavernosa, causing engorgement and rigidity.

Ischemic priapism

Most cases of priapism involve failure of detumescence and are most commonly due to failure of venous outflow (ie, low flow), also known as ischemic priapism. Severe pain from ischemia occurs after 4 hours. If prolonged > 4 hours, priapism can lead to corporeal fibrosis and subsequent erectile dysfunction Erectile Dysfunction Erectile dysfunction is the inability to attain or sustain an erection satisfactory for sexual intercourse. Most erectile dysfunction is related to vascular, neurologic, psychologic, and hormonal... read more or even penile necrosis and gangrene.

Stuttering priapism is a recurrent form of ischemic priapism with repeated episodes and intervening periods of detumescence.

Nonischemic priapism

Less commonly, priapism is due to unregulated arterial inflow (ie, high flow), usually as a result of formation of an arterial fistula after trauma. Nonischemic priapism is not painful and does not lead to necrosis. Subsequent erectile dysfunction is common.

Etiology of Priapism

In adults, the most common cause (see table Some Causes of Priapism Some Causes of Priapism Some Causes of Priapism ) is

In children, the most common causes are

In many cases, priapism may be idiopathic and recurrent.


Evaluation of Priapism


History of present illness should cover the duration of erection, presence of partial or complete rigidity, presence or absence of pain, and any recent or past genital trauma. The drug history should be reviewed for offending drugs, and patients should be directly asked about the use of recreational drugs and medications used to treat erectile dysfunction.

Physical examination

A focused genital examination should be done to evaluate extent of rigidity and tenderness and determine whether the glans and corpus spongiosum are also affected. Penile or perineal trauma and signs of infection, inflammation, or gangrenous change should be noted.

The general examination should note any psychomotor agitation, and the head and neck examination should look for pupillary dilation associated with stimulant use. The abdomen and suprapubic area should be palpated to detect any masses or splenomegaly, and a digital rectal examination should be done to detect prostatic enlargement or other pathology. Neurologic examination is useful to detect any signs of lower-extremity weakness or saddle paresthesias that might indicate spinal pathology.

Red flags

The following findings are of particular concern:

  • Pain

  • Priapism in a child

  • Recent trauma

  • Fever and night sweats

  • Perineal and/or lower extremity neurologic manifestations

Interpretation of findings

In patients with ischemic priapism, physical examination typically reveals complete rigidity with pain and tenderness of the corpus cavernosa and sparing of the glans and corpus spongiosum. By contrast, nonischemic priapism is painless and nontender, and the penis may be partially or completely rigid.


  • Complete blood count

  • Urinalysis and culture

  • Hemoglobin electrophoresis in Black people and men of Mediterranean descent

Treatment of Priapism

Treatment is often difficult and sometimes unsuccessful, even when the etiology is known. Whenever possible, patients should be referred to an emergency department; patients should preferably be seen and treated urgently by a urologist. Other disorders should be treated. For example, priapism often resolves when sickle cell crisis is treated. Measures used to treat priapism itself depend on the type.

Ischemic priapism

Treatment should begin immediately, typically with aspiration of blood from the base of one of the corpora cavernosa using a nonheparinized syringe, often with saline irrigation and intracavernous injection of the alpha-receptor agonist phenylephrine. For phenylephrine injections, 1 mL of 1% phenylephrine (10 mg/mL) is added to 19 mL of 0.9% saline to make 500 mcg/mL; 100 to 500 mcg (0.2 to 1 mL) is injected every 5 to 10 minutes until relief occurs or a total dose of 1000 mcg is given. Before aspiration or injection, anesthesia is provided with a dorsal penile nerve block or local infiltration.

If these measures are unsuccessful or if priapism has lasted > 48 hours (and is thus unlikely to resolve with these measures), a surgical shunt can be created between the corpus cavernosum and glans penis or corpus spongiosum and another vein.

Stuttering priapism

Stuttering priapism, when acute, is treated in the same way as other forms of ischemic priapism. There is a report of several cases caused by sickle cell disease Sickle Cell Disease Sickle cell disease (a hemoglobinopathy) causes a chronic hemolytic anemia occurring almost exclusively in people with African ancestry. It is caused by homozygous inheritance of genes for hemoglobin... read more Sickle Cell Disease that responded to a single oral dose of sildenafil. Treatments that may help prevent recurrences of stuttering priapism include antiandrogen therapy with gonadotropin-releasing hormone agonists, estrogen, bicalutamide, flutamide, phosphodiesterase type-5 inhibitors, and ketoconazole. The goal of antiandrogen therapy is to decrease the plasma testosterone level to < 10% of normal. Digoxin, terbutaline, gabapentin, and hydroxyurea have also been tried with some success.

Nonischemic priapism

Conservative therapy (eg, ice packs and analgesics) is usually successful; if not, selective embolization or surgery is indicated.

Refractory priapism

If other treatments are ineffective, a penile prosthesis can be placed.

Key Points

  • Priapism requires urgent evaluation and treatment.

  • Drugs (prescription and recreational) and sickle cell disease are the most common causes.

  • Acute treatment is with alpha agonists, needle decompression, or both.

Drugs Mentioned In This Article

Drug Name Select Trade
4-Way Nasal, Ah-Chew D, AK-Dilate, Anu-Med, Biorphen, Formulation R , Foster & Thrive Nasal Decongestion, Gilchew IR, Hemorrhoidal , Little Remedies for Noses, Lusonal, Mydfrin, Nasop, Nasop 12, Neofrin, Neo-Synephrine, Neo-Synephrine Cold + Allergy, Neo-Synephrine Extra Strength, Neo-Synephrine Mild, Ocu-Phrin, PediaCare Children's Decongestant, PediaCare Decongestant, PediaCare Infants' Decongestant, Sinex Nasal, Sudafed PE, Sudafed PE Children's Nasal Decongestant , Sudafed PE Congestion, Sudafed PE Sinus Congestion, Sudogest PE, Vazculep
LiQrev, Revatio, Viagra
Extina, Ketodan, Kuric, Nizoral, Nizoral A-D, Xolegel
Digitek , Lanoxicaps, Lanoxin, Lanoxin Pediatric
Brethaire, Brethine
Active-PAC with Gabapentin, Gabarone , Gralise, Horizant, Neurontin
DROXIA, HYDREA, Mylocel, Siklos
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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