Severe ACE Inhibitor Poisoning: Try Naloxone

ACE Inhibitor toxicity can result in severe bradycardia and profound hypotension. Consider naloxone to treat ACEI poisoning, especially in cases of severe hypotension in which aggressive administration of IV fluids would be a concern. Use of naloxone in this setting may also avoid the need to employ vasopressive support and pacing.

Several distinct families of endogenous opioids have been identified, with the most well-characterized being the endorphins, enkephalins, and dynorphins. Enkephalins have direct effects on blood pressure, heart rate, and the baroreceptor reflex. ACE inhibitors inhibit the metabolism of enkephalins thus potentiating their opioid effect which includes lowering of blood pressure. Administration of naloxone has been shown to increase blood pressure in ACE inhibitor overdoses.

References:
(1) Robert M, et al. Am J Emerg Med. 2019 Mar 28. [Epub ahead of print]
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(4) Maryland Poison Center, toxtidbits. January 2012. http://www.mdpoison.com