Opioids are a class of drugs that include the illegal drug heroin, synthetic opioids such as fentanyl, and pain relievers available legally by prescription, such as oxycodone (OxyContin®), hydrocodone (Vicodin®), codeine, morphine, and many others.  Learn about the health effects of prescription opioids and read the DrugFacts on Fentanyl, Heroin, and Prescription Opioids.

Common Names

Happy Pills, OC, Oxy, Oxycotton, Percs, Vikes

Fentanyl is a powerful synthetic opioid (80 times more potent than morphine) that since 2013 has driven the steep rise in opioid overdoses.

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Summary of Issue

All opioids are chemically related and interact with opioid receptors on nerve cells in the body and brain. Opioid pain relievers are generally safe when taken for a short time and as prescribed by a doctor, but because they produce euphoria in addition to pain relief, they can be misused (taken in a different way or in a larger quantity than prescribed, or taken without a doctor’s prescription). Regular use—even as prescribed by a doctor—can lead to dependence and, when misused, opioid pain relievers can lead to addiction, overdose incidents, and deaths.

An opioid overdose can be reversed with the drug naloxone when given right away. Improvements have been seen in some regions of the country in the form of decreasing availability of prescription opioid pain relievers and decreasing misuse among the nation’s teens. However, since 2007, overdose deaths related to heroin have been increasing. Fortunately, effective medications exist to treat opioid use disorders, including methadone, buprenorphine, and naltrexone.

A NIDA study found that once treatment is initiated, both a buprenorphine/naloxone combination and an extended release naltrexone formulation are similarly effective in treating opioid addiction. However, naltrexone requires full detoxification, so initiating treatment among active users was more difficult. These medications help many people recover from opioid addiction.

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Clinical Trials

Clinical trials are research studies in human volunteers conducted to answer specific health questions. Learn about the NIH-sponsored clinical trials available to you.