Priapism is a persistent, often painful erection that can last from several hours to a few days. It occurs when blood flows into the penis but is not adequately drained. Common causes of priapism include:

  1. Alcohol or drug abuse (especially cocaine)
  2. Certain medications, including some antidepressants and blood pressure medications
  3. Spinal cord problems
  4. Injury to the genitals
  5. Anesthesia
  6. Penile injection therapy (a treatment for erectile dysfunction)
  7. Blood diseases, including leukemia and sickle cell anemia