Fentanyl is a powerful synthetic drug that is similar to morphine and heroin but is 50 to 100 times more potent. Fentanyl and its analogs are members of the class of drugs known as rapid-acting synthetic opioids that alleviate pain. Other drugs in this class include fentanyl analogs, such as acetylfentanyl, butyrfentanyl, carfentanil, alfentanil, sufentanil and remifentanil. Fentanyl acts quickly to depress central nervous system and respiratory function. Exposure to fentanyl may be fatal.

The U.S. Drug Enforcement Administration (DEA) classifies fentanyl and some of its analogs as schedule II prescription drugs, which are typically used to treat patients with severe pain or to manage pain after surgery. They are sometimes used to treat patients with chronic pain who are physically tolerant to other opioids; however per the CDC Guideline for Prescribing Opioids for Chronic Pain, only clinicians who are familiar with the dosing and absorption properties of fentanyl and are prepared to educate their patients about its use and risks should consider prescribing it for chronic pain. Carfentanil is used in veterinary medicine as a sedative or anesthetic agent for large animals. Schedule II drugs, substances, or chemicals are defined as drugs with a high potential for abuse, with use potentially leading to severe psychological or physical dependence. These drugs, along with other fentanyl analogs which are not approved for medical purposes, are extremely dangerous when used illicitly.

Naloxone is a safe and effective antidote to all opioid-related overdoses, including fentanyl. It is a critical tool in preventing fatal opioid overdoses. Multiple doses of naloxone may be needed to treat a fentanyl overdose because of its high potency. Depending on state and local laws, naloxone can potentially be administered effectively by emergency responders, law enforcement, and others trained in its use.

For information on naloxone administration, see Drugs@FDA: FDA Approved Drug Productsexternal icon

Page last reviewed: November 15, 2016