Opioids are a class of drugs that include prescription painkillers such as oxycodone, hydrocodone, codeine, morphine, and fentanyl, as well as illegal drugs such as heroin. They bind to opioid receptors in the brain and body to reduce pain signals and produce feelings of pleasure and relaxation.

While opioids can effectively manage pain, they can also be highly addictive and have significant negative side effects, such as respiratory depression, sedation, and constipation. Misuse and abuse of opioids can lead to addiction, overdose, and death.

The opioid epidemic has become a major public health crisis in many countries, including the United States, where it is estimated that over 2 million people suffer from opioid use disorder, and tens of thousands die from opioid overdose each year. Efforts are being made to address the opioid epidemic through increased access to addiction treatment and harm reduction measures, as well as policies to reduce overprescribing and improve monitoring of opioid use.