People wondering “what is fentanyl” often turn to the National Institute on Drug Abuse (NIDA) for answers. The organization describes fentanyl as a pain-relieving drug that is up to 100 times more potent than the more well-known morphine. As a synthetic opioid analgesic, the Food and Drug Administration (FDA) maintains fentanyl as a Schedule II narcotic available only by prescription. Doctors typically prescribe fentanyl to patients struggling with severe and/or chronic pain and to manage post-surgical pain. People may not understand the potential for fentanyl overdose or fentanyl addiction when first prescribed the drug.