Published online Jun 26, 2015. doi: 10.5662/wjm.v5.i2.88
Peer-review started: August 27, 2014
First decision: November 27, 2014
Revised: January 9, 2015
Accepted: April 16, 2015
Article in press: April 20, 2015
Published online: June 26, 2015
Processing time: 315 Days and 0.5 Hours
This paper reviews milestones in antidotal therapies for cyanide (CN) spanning early remedies, current antidotal systems and research towards next generation therapies. CN has been a part of plant defense mechanisms for millions of years. It became industrially important in the nineteenth century with the advent of CN assisted gold mining and the use of CN as a pest control agent. The biochemical basis of CN poisoning was actively studied and key mechanisms were understood as early as 1929. These fundamental studies led to a variety of antidotes, including indirect CN binders that generate methemoglobin, direct CN binders such as hydroxocobalamin, and sulfur donors that convert CN to the less toxic thiocyanate. Research on blood gases at the end of the twentieth century shed new light on the role of nitric oxide (NO) in the body. The discovery of NO’s ability to compete with CN for enzymatic binding sites provided a previously missed explanation for the rapid efficacy of NO generating antidotes such as the nitrites. Presently used CN therapies include: methemoglobin/NO generators (e.g., sodium nitrite, amyl nitrite, and dimethyl aminophenol), sulfur donors (e.g., sodium thiosulfate and glutathione), and direct binding agents [(e.g., hydroxocobalamin and dicobalt salt of ethylenediaminetetraacetic acid (dicobalt edetate)]. A strong effort is being made to explore novel antidotal systems and to formulate them for rapid administration at the point of intoxication in mass casualty scenarios. New antidotes, formulations, and delivery systems are enhancing bioavailability and efficacy and hold promise for a new generation of improved CN countermeasures.
Core tip: This paper reviews milestones in antidotal therapies for cyanide (CN) spanning early history, current antidotal systems, and research towards next generation therapies. Presently used CN therapies include: methemoglobin/nitric oxide generators (e.g., sodium nitrite, amyl nitrite, and dimethyl aminophenol), sulfur donors (e.g., sodium thiosulfate and glutathione), and direct binding agents (e.g., hydroxocobalamin and dicobalt edetate). New antidotes, formulations, and delivery systems are presently being developed for rapid administration at the point of intoxication in mass casualty scenarios. These hold promise for a new generation of improved CN countermeasures.