Opioids

What is an opiate antagonist?

Fiona Kennedy
Written byFiona Kennedy
Dr Olalekan Otulana
Medically Reviewed by Dr Olalekan Otulana MBChB, MRCGP, FRSPH, MBA Addiction Specialist Physician
Last updated:
8 August 2025

Naloxone and naltrexone are commonly used opiate antagonist drugs which are competitive antagonists that bind to the opioid receptors with higher affinity than agonists but do not activate the receptors. This effectively blocks the receptor, preventing the body from responding to opioids and endorphins. Naltrexone and Naloxone are commonly used in opiate and opioid addiction treatment.

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