Priapism is a medical term for a potentially dangerous and painful condition in which a man’s penis becomes aroused without psychological or physical stimulation and remains in this state for more than four hours even after intercourse has ended. The reason usually lies in circulatory disorders, in which blood is not removed normally from the penis.

In cases of painful arousal in men lasting more than four hours, a specialist or emergency room should be contacted immediately, as these can often be life-threatening.

The condition is a medical emergency, as it is associated with reduced fresh blood flow to the genital tissues, which can lead to hypoxic lesions, erectile dysfunction and impotence, and in more severe cases: gangrene.

Some drugs and substances are known to have side effects leading to priapism. In the first place are papaverine and alprostadil – the active ingredients of many drugs that treat erectile dysfunction. But similar side effects also appear in unexpected places: antidepressants such as trazodone; anticoagulants; cantharides, such as the famous “Spanish fly” and some drugs – alcohol, heroin, cocaine. But the strangest cause of this condition remains the bite of the Brazilian wandering spider – Phoneutria nigriventer and its relative – Latrodectus hesperus, called the “Black Widow”.

Priapism is not only a male problem, women also have similar problems. Clitoris is the medical term for prolonged and painful clitoral arousal that is also unrelated to sexual desire. While this condition is not associated with more serious complications in women, the pain can greatly disrupt their daily lives.

Only in the past few years have scientists begun to understand the causes of this dangerous condition. Dr. Yang Xia and his team at the University of Texas Medical Center found that the absence or reduced amount of a specific protein called ADA, which is responsible for breaking down the adenosine molecule, causes priapism.