Naloxone is used to treat opioid overdose because it

Naloxone is used to treat opioid overdose because it

• A. Antagonizes opioid receptors and reverses effects
• B. Accelerates opioid metabolism
• C. Increases dopamine release
• D. Has strong oral bioavailability

Answer: (A)

Naloxone reverses opioid overdose by blocking the receptors that opioids activate. It acts as a competitive antagonist at mu receptors (with activity at kappa and delta to a lesser extent), so it quickly displaces opioids from these sites. By occupying the receptor, it stops the opioid from producing effects like respiratory depression and sedation, rapidly restoring breathing. This mechanism explains why naloxone is effective in overdose and why its effect is temporary if long-acting opioids are involved, often requiring repeated dosing. It does not speed up the body's metabolism of opioids, increase dopamine release, or have good oral bioavailability (in fact, it has poor oral bioavailability, hence parenteral or intranasal routes are used).

Naloxone reverses opioid overdose by blocking the receptors that opioids activate. It acts as a competitive antagonist at mu receptors (with activity at kappa and delta to a lesser extent), so it quickly displaces opioids from these sites. By occupying the receptor, it stops the opioid from producing effects like respiratory depression and sedation, rapidly restoring breathing. This mechanism explains why naloxone is effective in overdose and why its effect is temporary if long-acting opioids are involved, often requiring repeated dosing. It does not speed up the body's metabolism of opioids, increase dopamine release, or have good oral bioavailability (in fact, it has poor oral bioavailability, hence parenteral or intranasal routes are used).