Glossary of Pharmacology 

Competitive antagonist

An antagonist that prevents the biological response of the agonist by competing with the agonist for the same binding site of the receptor. The antagonist typically has high affinity for the receptor compared to the agonist and therefore it prevents the binding and biological response elicited by an agonist.

Example:

Naloxone is an antagonist of the µ-opioid receptor, and it reverses analgesia and respiratory depression of opioids by competing on the same binding site on the receptor 

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