Naloxone is used to reverse overdose caused by which class of drugs?

• A. Sedatives
• B. Opioids
• C. Stimulants
• D. Cyanide

Answer: (B)

Naloxone works by blocking opioid receptors, specifically the mu receptors in the brain. In opioid overdose, opioids such as heroin or morphine activate these receptors and depress respiration. Naloxone is a competitive antagonist, so it binds to the same receptors with high affinity and displaces the opioid, rapidly reversing the dangerous respiratory depression and sedation.

Because this mechanism is specific to opioids, naloxone reverses overdoses caused by opioid drugs. It won’t reverse overdoses from sedatives that act on GABA receptors, stimulants that boost monoamine activity, or toxins like cyanide, which require different antidotes and treatments. Keep in mind that naloxone’s effects can wear off before some opioids wear off, so patients must be monitored for re-narcotization and may need additional dosing.