Naloxone (Narcan) given to the patient in an opioid overdose will:

• A. Decrease the respiratory rate
• B. Enhance the effect of narcotic analgesic preparations
• C. Slow the heart rate
• D. Prevent or reverse the effects of opioids

Answer: (D)

Naloxone reverses opioid effects by acting as an opioid receptor antagonist. It competes with opioids for mu receptors and binds to them, displacing the opioid molecules and blocking their actions. This reversal of receptor activity stops the opioid-induced CNS and respiratory depression, effectively restoring breathing and consciousness in an overdose. In practice, this means rapid improvement in respiration and mental status, although the effect can be shorter than the opioid’s duration, so repeated dosing or monitoring may be needed. It can also precipitate withdrawal in people who are opioid-dependent. It will not decrease respiratory rate or slow the heart; it counteracts those opioid effects and can restore normal function.