OUTLINE: This is a double blinded, randomized study. After all patients have undergone radical prostatectomy, hydromorphone is administered in two different ways. Patients receive either a hydromorphone bolus injection through an epidural catheter using a patient controlled analgesia pump or a hydromorphone bolus injection through an intravenous catheter using a patient controlled analgesia pump. Infusion for both groups is stopped at 24 hours. Patients are followed every 30 minutes for 6 hours.