The danger of cyanide poisoning in fires is especially high in industrialized countries. This is because wherever people live and work, they are increasingly surrounded by growing numbers of plastic products — and very many plastics contain cyanides. When these materials burn, they release cyanide vapors as a constituent of the smoke. The public perception is that carbon monoxide poisoning is by far the most dangerous consequence of smoke inhalation. A current study by the Paris Fire Department, however, emphasizes that cyanide poisoning presents at least as great a danger — 87 percent of all fatal fire casualties showed toxic levels of cyanide in their blood.

Cyanide kills by internal suffocation. In the process, it binds to the trivalent iron of the enzyme cytochrome-c oxidase, which is needed for the respiratory chain in the mitochondria of the cell. As a result, the internal or cellular respiration is disrupted, along with its adenosine triphosphate production.

The patient is helped by administration of active agents to which the cyanide ions have a higher affinity than they do to cytochrome-c oxidase. Active agents such as the methemoglobin generator 4-dimethylaminophenol are first administered once a blood test has confirmed that cyanide poisoning is likely. This is because this therapy requires subsequent further treatment steps such as administration of sodium thiosulfate in order to remove the cyanide from the blood.

Hydroxocobalamin, the active ingredient of Cyanokit®, does not result in limitation of oxygen uptake due to blockage of the hemoglobin in the blood typical of 4-dimethylaminophenol. Every hydroxocobalamin molecule can bind one cyanide ion. The resulting cyanocobalamin is a stable, non-toxic substance that is excreted via the kidneys. Cyanokit® can therefore also be administered if cyanide poisoning is suspected and in cases where carbon monoxide poisoning is simultaneously present.