Opioid analgesic

Opioid
Drug class
Harvesting the poppy pod
Class identifiers
Use	pain relief
ATC code	N02A
Mode of action	opioid receptor
External links
MeSH	D000701

Opioids are substances that act on opioid receptors to produce morphine-like effects. Opioids are most often used medically to relieve pain, and by people addicted to opioids. Opioids include opiates, an older term that refers to such drugs derived from opium, including morphine itself. Other opioids are semi-synthetic and synthetic drugs such as hydrocodone, oxycodone and fentanyl; antagonist drugs such as naloxone and endogenous peptides such as the endorphins. The terms opiate and narcotic are sometimes encountered as synonyms for opioid. Opiate is properly limited to the natural alkaloids found in the resin of the opium poppy although some include semi-synthetic derivatives.Narcotic, derived from words meaning numbness or sleep, as an American legal term, refers to cocaine and opioids, and their source materials; it is also loosely applied to any illegal or controlled psychoactive drug. In other jurisdictions all controlled drugs are legally classified as narcotics. The term can have pejorative connotations and its use is generally discouraged where that is the case.

Primarily used for pain relief, including anesthesia they are also used to suppress cough, suppress diarrhea, treat addiction, reverse opioid overdose, and suppress opioid induced constipation.Extremely strong opioids are approved only for veterinary use such as immobilizing large mammals. Opioids act by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract. These receptors mediate both the psychoactive and the somatic effects of opioids. Opioid drugs include partial agonists and antagonists, which produce moderate or no effect (respectively) but displace other opioids from binding in those receptors.