Merck Manual

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Some Causes and Features of Priapism

Some Causes and Features of Priapism


Common Features*


Drugs for erectile dysfunction (such as alprostadil, papaverine, phentolamine, avanafil, sildenafil, tadalafil, or vardenafil)

Painful priapism in men who took one of these drugs immediately before priapism started

Only a doctor's examination

Recreational drugs (such as amphetamines and cocaine)

Painful priapism

If amphetamines or cocaine is the cause, agitation and anxiety

A doctor's examination

Occasionally drug screening

Other drugs (such as anticoagulants, certain antidepressants, antihypertensive drugs, psychostimulants, antipsychotic drugs, corticosteroids, or lithium)

Painful priapism in boys or men being treated for a disorder

Only a doctor's examination

In boys or young men, often of African or Mediterranean descent

A complete blood count

Blood tests to check for abnormal hemoglobin (hemoglobin electrophoresis)

Prostate cancer that has spread to areas next to the prostate or any cancer that has spread to the genitals

In men over 50 who have worsening symptoms indicating that the opening from the bladder into the urethra (bladder outlet) is blocked (such as a weak urine stream, difficulty starting urination, and dribbling at the end of urination)

Sometimes blood in the urine

Blood tests to measure the level of prostate-specific antigen


Spinal cord disorders, such as narrowing of the spinal canal (spinal cord stenosis) or compression of the spinal cord

Weakness or numbness in the legs

MRI or CT of the spine

Injury to an artery

Mildly painful and slightly rigid priapism

In men who have had a recent injury to the penis or groin area

Duplex ultrasonography of the penis (ultrasonography that measures blood flow and shows structure of the blood vessels through which the blood is flowing)

Angiography (x-rays of blood vessels)


* Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present.

CT = computed tomography; MRI = magnetic resonance imaging.