Mechanism of Action:
Naloxone is a mu (μ)-opioid receptor competitive antagonist, and also has an antagonist action with a lower affinity, at κ- and δ-opioid receptors. It blocks the action of both exogenous opioids (e.g. morphine, diamorphine) and endogenous opioids on opioid receptors in the central nervous system. Opioid receptors are G-protein-coupled receptors and inhibit adenylate cyclase. They cause hyperpolarisation (by opening potassium channels causing K+ to move out of cells) and prevent transmitter release (by blocking calcium channels).
Naloxone is a derivative of the opioid oxymorphone, with the substitution of the N-methyl group with an allyl (prop-2-enyl) group to give N-allyl oxymorphone.
Indications
- Reversal of opiate toxicity
Lecture and CAL materials: (under review)
- Lecture: Pain and Analgesia (Lecture 2): Analgesics and other drugs used to treat pain
- CAL: G Proteins