Nassau County EMT Practice Test

Naloxone (Narcan) works by quickly displacing opioids from opioid receptors, reversing respiratory depression and sedation in opioid overdose. In a patient who is in cardiac arrest, the heart’s primary problem is lack of circulation, not opioid-induced respiratory depression. Giving naloxone in this moment doesn’t restore cardiac activity and won’t improve outcome from the arrest. It can also provoke a sudden sympathetic surge—tachycardia, hypertension, agitation—that raises myocardial oxygen demand and can complicate resuscitation or trigger arrhythmias. Because there’s no goal to reverse an opioid effect driving the arrest, and because it can interfere with critical resuscitation efforts, Narcan is not indicated in cardiac arrest. If there were clear signs of opioid overdose with respiratory depression in a non-arrest scenario, naloxone would be appropriate, but during cardiac arrest it’s avoided.