Category:Opioids

An opioid is a chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract. The receptors in these organ systems mediate both the beneficial effects and the side effects of opioids.

Opiates are among the world's oldest known drugs; the use of the opium poppy for its therapeutic benefits predates recorded history. The analgesic (painkiller) 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, constipation, and a strong subjective sense of euphoria. Opioids can cause cough suppression, which can be both an indication for opioid administration or an unintended side effect. Opioid dependence can develop with ongoing administration, leading to a withdrawal syndrome with abrupt discontinuation. Opioids are well known for their ability to produce a feeling of euphoria, motivating some to recreationally use opioids.

Classes of opiates

• Natural opiates: alkaloids contained in the resin of the opium poppy, primarily morphine, codeine, and thebaine, but not papaverine and noscapine which have a different mechanism of action; The following could be considered natural opiates: The leaves from Mitragyna speciosa (also known as Kratom) contain a few naturally-occurring opioids, active via Mu- and Delta receptors. Salvinorin A, found naturally in the Salvia divinorum plant, is a kappa-opioid receptor agonist.
• Semi-synthetic opioids: created from the natural opiates, such as hydromorphone, hydrocodone, oxycodone, oxymorphone, desomorphine, nicomorphine, dipropanoylmorphine, benzylmorphine and ethylmorphine and buprenorphine;
• Fully synthetic opioids: such as fentanyl, pethidine, methadone, tramadol and dextropropoxyphene;
• Endogenous opioid peptides, produced naturally in the body, such as endorphins, enkephalins, dynorphins, and endomorphins. Sometimes morphine, and some other opioids, which are produced in small amounts in the body, are included in this category.