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Cyanide poisoning

Shoma Desai, MD
Mark Su, MD, MPH
Section Editor
Stephen J Traub, MD
Deputy Editor
Jonathan Grayzel, MD, FAAEM


Cyanide is a mitochondrial toxin that is among the most rapidly lethal poisons known to man. Used in both ancient and modern times as a method of execution, cyanide causes death within minutes to hours of exposure. Though significant cyanide poisoning is uncommon, it must be recognized rapidly to ensure prompt administration of life-saving treatment. A summary table to facilitate emergent management is provided (table 1).

This topic review will discuss the toxicity and management of cyanide poisoning. A general approach to the poisoned patient is found elsewhere. (See "General approach to drug poisoning in adults".)


According to the Toxic Exposure Surveillance System, there were 3165 human exposures to cyanide from 1993 to 2002. Of these, 2.5 percent were fatal [1]. Cyanide poisoning may result from a broad range of exposures (table 2).

Fire – In industrialized countries, the most common cause of cyanide poisoning is domestic fires [2]. Cyanide can be liberated during the combustion of products containing both carbon and nitrogen. These products include wool, silk, polyurethane (insulation/upholstery), polyacrylonitriles (plastics), melamine resins (household goods), and synthetic rubber [3-5]. Vehicular fires can also expose victims to cyanide. Toxicologic evaluation of passengers following the explosion in 1985 of a Boeing 737 during take-off in Manchester, England, revealed that 20 percent of the 137 victims who escaped had dangerously elevated levels of carbon monoxide, while 90 percent had dangerously elevated levels of cyanide [6]. Overall, it is reported that significant levels of cyanide are present in up to 35 percent of all fire victims [7].

Industrial – Worldwide industrial consumption of cyanide is estimated to be 1.5 million tons per year, and occupational exposures account for a significant number of cyanide poisonings [8]. Metal extraction in mining, electroplating in jewelry production, photography, plastics and rubber manufacturing, hair removal from hides, and rodent pesticide and fumigants have all been implicated in cyanide poisonings. Skin contact with cyanide salts can result in burns, which allow for enhanced absorption of cyanide through the skin. The combination of cyanide salts and acid, as utilized in electroplating, results in the release of cyanide gas, which can lead to lethal inhalational exposures. Splashes of cyanide solutions can result in dermal as well as mucosal absorption [2,9].

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Literature review current through: Nov 2017. | This topic last updated: Sep 28, 2016.
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