One complication or side effect of any medication for erectile dysfunction is something known as priapism, or a prolonged and painful penile erection lasting for more than four hours. This can be thought of as the body's inability to reverse an erection back to the flaccid or soft state.
Usually, under normal physiological conditions, when a man has an orgasm or there is lack of sexual stimulation, the body reverses the erection by constricting or "closing" the major blood vessels that...

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