Opioid

An opioid is a chemical that works by binding to opioid receptors, which are found principally in the central nervous system and the gastrointestinal tract. The receptors in these two organ systems mediate both the beneficial effects and the side effects of opioids.
The analgesic (pain relieving) effects of opioids are due to decreased perception of pain, decreased reaction to pain as well as increased pain tolerance. The side effects of opioids include sedation, respiratory depression, and constipation. Opioids can cause cough suppression, which can be both an indication for opioid administration or an unintended side effect. Physical dependence can develop with ongoing administration of opioids, leading to a withdrawal syndrome with abrupt discontinuation. Opioids can produce a feeling of euphoria, and this effect, coupled with physical dependence, can lead to recreational use of opioids by some individuals. However, misuse of opioids in this manner is uncommon in patients prescribed opioids for the treatment of pain.
Although the term opiate is often used as a synonym for opioid, it is more properly limited to the natural alkaloids found in the resin of the opium poppy and, more loosely, the semi-synthetic opioids derived from them.
==See also==
*Antidepressant
Category:Antidepressants