Opioids

Opioids are a class of medications and substances that primarily affect the mu opioid receptor, in the central nervous system. Opioids comprise natural opiates and synthetic and semi-synthetic opioids. Opioids can have a medical purpose for the treatment of pain, like prescribed opioid medications. Opioids can also have a non-medical purpose such as heroin, a substance that can be ingested, inhaled, or injected.