When cyanides come to mind, we first think of poison, not medicine. This is not surprising, as the cyanides have very limited medical uses: Laetrile was widely promoted in the 1970s for the treatment of cancer, without established benefit, and sodium nitroprusside is currently used in emergency situations to reduce markedly elevated blood pressure.
The cyanides are extremely effective poisons used to kill humans, animal pests, and insects. Among the most rapid-acting poisons, hydrogen cyanide (prussic acid)—the most important cyanide—is a colorless gas with a characteristic bitter almond odor. Depending on the concentration inhaled, it can cause toxic effects and death from cardiac arrest within seconds to minutes. By inhibiting the tissue enzyme cytochrome oxidase, it prevents all body cells from using oxygen.
POISON OF CHOICE FOR SUICIDE. Berlin colormaker Heinrich Diesbach first synthesized hydrogen cyanide in 1704 from the dye Prussian blue. It has been most extensively used for executions and suicides. Although lethal injection is the most commonly used method of capital punishment in the United States, several states utilize gas chamber executions using cyanide gas. Hydrogen cyanide’s most infamous use was for the mass extermination of inmates at Nazi concentration camps during the Holocaust. Because of its speed and dependability, such senior Third Reich members as Goebbels, Himmler, and Göring used liquid hydrogen cyanide for suicidal purposes in 1945–46. In 1978, more than 900 members of the Peoples Temple cult died in Jonestown, Guyana, after ingesting a flavored drink containing potassium cyanide.
Poisonings have resulted from exposure to cyanide in agricultural fumigants and chemical laboratory accidents. Combustion of certain plastics release hydrogen cyanide and are thought to have been responsible for airplane fires that killed 119 passengers in Paris (1973) and 303 pilgrims in Riyadh, Saudia Arabia (1980).
Hydrogen cyanide is rarely used in criminal poisonings because the rapid onset of death and the bitter almond odor provide a strong inference of foul play. In 1982, seven individuals in the Chicago area died after ingesting Tylenol (acetaminophen/paracetamol) capsules to which potassium cyanide had been criminally added; the perpetrator was never apprehended. To prevent such scenarios, tamper-resistant drug containers are now routinely used.
SEE ALSO Acetaminophen/Paracetamol (1953).
In this Nazi gas chamber located at the Sztutowo concentration camp in Poland, more than 60,000 people are estimated to have perished from hydrogen cyanide gas between 1939 and 1945.