Opioids

From Proteopedia

Opioids, broadly defined, are molecules that bind in the ligand-binding pocket of opioid receptors. These include morphine, endorphins, fentanyl and many other legal or illegal drugs. Sometimes, opioids are distinguished from opiates, drugs that are derived from opium by purification and sometimes modification. Opioids acting as agonists when bound to opioid receptors may be used as pain medication, among other effects and side-effects. Opioids such as naloxone acting as antagonists, on the other hand, prevent agonists from binding and turn off the receptor. All opioids are addictive, and can lead to death by overdosing.