Naloxone is used to treat opioid overdose by:

• A. Stimulating opioid receptors
• B. Increasing insulin release
• C. Blocking opioid receptors
• D. Causing vasodilation

Answer: (C)

Naloxone works by blocking opioid receptors. It acts as a competitive antagonist at opioid receptor sites, especially the mu receptors. When given during an overdose, it binds to these receptors with higher affinity than opioids, displacing the opioid molecules already attached. This quickly reverses the opioid-induced respiratory depression and decreased consciousness, effectively restoring breathing and alertness as long as naloxone is active. It doesn’t stimulate receptors, so it doesn’t worsen overdose, and its primary action isn’t related to insulin release or causing vasodilation. Keep in mind that naloxone’s effects may wear off before the opioids are cleared, so monitoring and possible additional dosing are important.