Priapism (Prolonged Erection)

Priapism is a persistent erection that lasts longer than four hours and is unrelated to, or continues well beyond, sexual arousal. It is not a sign of health or virility. It is a urological emergency.

There are two main types. Ischaemic (low-flow) priapism is by far the most common and the dangerous one: blood becomes trapped in the erection chambers and cannot drain, so the tissue is starved of oxygen. It is usually rigid and increasingly painful. Non-ischaemic (high-flow) priapism is rarer, usually follows an injury to the groin or perineum, is often not painful, and is less of an emergency, though it still needs assessment.

The distinction matters because the treatments differ, but you cannot reliably tell the two apart at home. A painful, rigid erection lasting over four hours should be treated as ischaemic and as an emergency until a doctor says otherwise.

The single most important factor in the outcome is time. The sooner normal blood flow is restored, the more likely erectile function is preserved.

Ischaemic priapism has several recognised triggers. The most common in a men's health setting is injection therapy for erectile dysfunction. Alprostadil and compounded mixtures such as TriMix (papaverine, phentolamine and alprostadil) work by relaxing the penile blood vessels, and an overly strong response can leave the erection trapped. This is why first doses are supervised and doses are titrated carefully.

Several medicines can cause it. Trazodone, an antidepressant sometimes used for sleep, is the classic example; some other antidepressants, antipsychotics and blood-pressure medicines are also linked. Recreational drugs and heavy alcohol raise the risk too.

Medical conditions matter as well. Sickle cell disease and other blood disorders are important causes worldwide, and priapism can be the first sign. Pelvic or perineal injury typically causes the non-ischaemic (high-flow) type. In some cases no cause is found.