opioid

(noun)

Any of a class of psychoactive chemicals that works by binding to opioid receptors in the nervous system; among the world's oldest known drugs, the analgesic effects of opioids are due to decreased perception of pain, decreased reaction to pain, and increased pain tolerance.

Related Terms

Examples of opioid in the following topics:

  • Analgesia: Relief from Pain

    • This reduces pain and also inflammation (in contrast to paracetamol and the opioids).
    • Morphine, the archetypal opioid, and various other substances (e.g. codeine, oxycodone, hydrocodone, dihydromorphine, and pethidine) all exert a similar influence on the cerebral opioid receptor system.
    • Dosing of all opioids may be limited by opioid toxicity (confusion, respiratory depression, myoclonic jerks, and pinpoint pupils) and seizures (tramadol), but there is no dose ceiling in patients who accumulate tolerance.
    • Opioids, while very effective analgesics, may have some unpleasant side-effects.
    • Pruritus (itching) may require switching to a different opioid.

  • Epidural Anesthesia

    • It can be used as an addition to general anesthesia, reducing the patient's need for opioid analgesics.

  • Adrenal Medulla

    • All of these peptides bind to opioid receptors and produce analgesic (and other) responses.

  • Renal Calculi

    • For symptomatic stones, pain control is usually the first measure, using medications such as non-steroidal anti-inflammatory drugs or opioids.

  • The Anterior Pituitary

    • Beta-endorphin is a polypeptide that effects the opioid receptor, whose effects include the inhibition of the perception of pain.

  • Types of Neurotransmitters by Function

    • Addictive drugs such as cocaine and amphetamine exert their effects primarily on the dopamine system, while addictive opiates and functional analogs of opioid peptides which regulate dopamine levels.

  • Intubation During Anesthesia

    • General anesthetic agents, opioids, and neuromuscular-blocking drugs may diminish or even abolish the respiratory drive.

  • Vomiting

    • Antiemetics are typically used to treat motion sickness and the side-effects of medications such as opioids and chemotherapy.