Question

QUESTION 13 Describe different specific clinical situations where agonists, antagonists, and partial agonists would be used.

Answer 1

Full agonists bind tightly to the opioid receptors and undergo significant conformational change to produce maximal effect. For example is morphine, which mimics the actions of endorphins at μ-opioid receptors throughout the central nervous system.

Partial agonists are agents that possess both agonist/antagonist activities cause less conformational change and receptor activation than full agonists. At low doses, partial agonists may provide similar effects to their full agonist members However, when the dose of partial agonists increases, the analgesic activity will plateau, and further increases in doses will not provide additional relief but may increase the adverse effects. Agents like buprenorphine are used to treat dependence for this reason, as they produce milder effects on the opioid receptor with lower dependence and abuse potential.

There are antagonists, which demonstrate opposing activity depending on the opioid receptor. For eg Naloxone is a mu-opioid receptor antagonist and reversal agent used to mitigate risk for opioid-induced respiratory depression