Hello all! I am Joe and I am here to discuss my father’s condition with you. My father is a cancer patient. He is suffering from bone cancer. Its his spine which is infected with this. He is receiving anti-cancer medication but simultaneously he is also being administered a narcotic analgesic. He was given hydrocodone previously but it was not all that potent. Now he has been given fentanyl. I want to know about the fentanyl side-effects?