8th January 2024

Mechanism of action

The three best-known opiate receptors are mu, kappa, and delta. The most clinically significant is the mu receptor. Most opioid metabolites act as agonists at this receptor. Receptor antagonists such as Naloxone are used in reversal of opioid side effects.

Nociceptive pain increases the number of opiate receptors peripherally. Opioids act upon these receptors peripherally to give analgesia.