Opioid

An opioid is any agent that binds to opioid receptors found principally in the central nervous system and gastrointestinal tract. There are four broad classes of opioids: endogenous opioid peptides, produced in the body; opium alkaloids, such as morphine (the prototypical opioid) and codeine; semi-synthetic opioids such as heroin and oxycodone; and fully synthetic opioids such as pethidine and methadone that have structures unrelated to the opium alkaloids.

Related Topics:
Opioid receptor - Central nervous system - Gastrointestinal tract - Endogenous - Peptide - Opium - Alkaloids - Morphine - Codeine - Heroin - Oxycodone - Pethidine - Methadone

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Although the term opiate is often used to refer to all opium-like drugs, it is more properly limited to the natural opium alkaloids and the semi-synthetics derived from them.

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