After naloxone administration for an opioid overdose, approximately how long until capacity is restored?

• A. 30 minutes
• B. 60 minutes
• C. 90 minutes
• D. 120 minutes

Answer: (C)

Naloxone reverses opioid effects by competitively blocking mu-opioid receptors, rapidly restoring breathing and consciousness. The reversal lasts only while naloxone is active in the body, so the window in which capacity returns is tied to its own duration. For typical overdoses involving short-acting opioids, this regained function usually occurs within about 90 minutes after administration.

But this is not universal. If a longer-acting opioid is involved, or if a high opioid dose is present, the naloxone effect can wear off while the opioid effect persists, leading to re-sedation or respiratory depression. In those cases, repeated dosing or an infusion and extended medical monitoring are needed. That’s why clinicians emphasize watching the patient for several hours after reversal, even if initial recovery looks complete.