Prolonged, painful erections can be disturbing. That's why commercials for erectile dysfunction drugs always issue warnings about the condition, called priapism. This type of erection lasts more than four hours, can be painful and is not related to sexual stimulation, according to the Sexual Medicine Society of North America.

Whether priapism occurs during the day or at night, it might be dangerous depending on the cause. There are different types of priapism and other painful erections, and their treatment varies depending on the cause.

Regardless of the type of priapism, a sufferer must seek medical attention.

Priapism and sleep-related painful erections

In addition to three kinds of priapism, a man can also experience sleep-related painful erections (SRPEs). While similar in symptoms, each of these conditions is, in fact, very different.

Ischemic (or low-flow) priapism

Ischemic priapism refers to a condition where the penis is erect, but doesn't experience normal blood flow, said