Cyanide is a poisonous, fast-acting chemical which may come in many forms. Cyanide can exist in the form of a colourless gas, such as hydrogen cyanide (HCN) or cyanogen chloride (CNCl), or as a crystal, such as sodium cyanide (NaCN) or potassium cyanide (KCN). It is also known as AC (hydrogen cyanide) and CK (cyanogen chloride)
Cyanide is a lethal poison. It just takes 100mg to kill someone, and it happens quickly. Depending on the quantity and mode of administration, death can occur in as little as a minute or as long as 15 excruciating minutes.
The stench of cyanide is sometimes characterised as “bitter almond,” however it does not always emit an odour, and not everyone can notice it.
During World War I, this toxin was first utilised as a chemical weapon in the form of a gas, and then in the Nazi gas chambers during the Holocaust. During the Iran-Iraq War in the 1980s, it was employed against Kurdish residents of northern Iraq.
Forms of Cyanide
Cyanide can be found as a gas, a liquid, or a solid. Hydrogen cyanide liquid is extremely volatile, however, and heats off /vaporises to a gas at warm room temperatures (78.1˚F / 25.6˚C). The liquid ranges in hue from nearly colourless to a translucent pastel blue.
Solid cyanide is present in crystalline form, primarily as sodium or potassium cyanide, although the crystals are so fine that they appear to be a white powder.
Where to find?
Some foods and plants, such as cassava, lima beans, and almonds, emit cyanide as a natural byproduct. Chemicals that are converted to cyanide may be present in the pits and seeds of common fruits including apricots, apples, and peaches. These compounds are far less abundant in the plant’s edible components.
Cigarette smoke and synthetic material combustion products, such as plastics, contain cyanide. When things burn, they emit combustion products.
-> In metallurgy, cyanide salts are used for electroplating, metal cleaning, and extracting gold from its mine.
-> Cyanide is used in the making of paper, textiles, and polymers.
-> In ships and buildings, cyanide gas is used to kill bugs and rodents.
-> It’s in the chemicals that are used to develop picture.
A person can be exposed to cyanide via breathing cyanide-contaminated air, drinking cyanide-contaminated water, eating cyanide-contaminated food, or touching cyanide-contaminated soil. Both natural and anthropogenic processes can cause cyanide to enter water, soil, or the air.
Smoking cigarettes is undoubtedly one of the most common and major sources of cyanide exposure. One of the tobacco smoke hazardous chemicals is hydrogen cyanide, which is generated when protein and nitrate molecules in tobacco are burned at high temperatures in an oxygen-deficient condition.
Cyanide gas in the form of hydrogen cyanide or cyanogen chloride, at levels of 2,500-5,000 mg•min/m^3 and 11,000 mg•min/m^3, is expected to be lethal to 50 percent of the exposed persons (LD50). The deadly dose is 100-200 mg when consumed as sodium or potassium cyanide.
Signs & Symptoms
The crime of cyanide poisoning can be difficult to identify. Because cyanide stops the body’s cells from using oxygen, the effects of cyanide poisoning appear as suffocating, with first symptoms akin to shortness of breath. It prevents a crucial enzyme in the mitochondria of cells from capturing oxygen and transferring it into the cells. Because the heart and brain utilise a lot of oxygen, cyanide is more dangerous to them than to other organs.
Because oxygen remains in the blood rather than moving to the body’s cells, the most noticeable telltale sign of cyanide poisoning is an abnormally pink (or even cherry-red) tint to the victim’s complexion. The body is just oxygen-depleted. The person may breathe quickly and have a fast heartbeat at first, but as oxygen deprivation worsens, the beating will slow.
Another distinct symptom of cyanide poisoning is that the victim’s breath may smell faintly like bitter almonds, but this odour may be so subtle that it goes unnoticed.
- Nausea and vomiting
- Rapid breathing
- Rapid heart rate
Other health problems may occur as a result of exposure to a substantial amount of cyanide via any route:
- Consciousness loss
- Low blood pressure
- Lung injury
- Respiratory failure that results in death
- Slow heart rate
In a hospital, cyanide poisoning is treated with particular antidotes and supportive medical care. Activated Charcoal may be administered to help absorb the toxin and safely clear it from body.
Antidotes to cyanide exist, each with its own method of action and toxicological, clinical, and risk-benefit profiles.
Doctor may administer one of two antidotes:
- Cyanide antidote kit
- Hydroxocobalamin (Cyanokit)
The cyanide antidote kit contains three medications: amyl nitrite, sodium nitrite, and sodium thiosulfate, which are given together.
The first-line treatment for cyanide toxicity is hydroxocobalamin (HCO, vitamin B-12).
Sodium thiosulfate works as a sulphur donor, allowing the enzyme rhodanese to detoxify cyanide to thiocyanate, whereas hydroxocobalamin binds to cyanide and creates the harmless cyanocobalamin, which is eliminated through the renal.
Source & Reference
- Culnan DM, Craft-Coffman B, Bitz GH, Capek KD, Tu Y, Lineaweaver WC, Kuhlmann-Capek MJ. Carbon Monoxide and Cyanide Poisoning in the Burned Pregnant Patient: An Indication for Hyperbaric Oxygen Therapy. Ann Plast Surg. 2018 Mar;80(3 Suppl 2):S106-S112.
- Parker-Cote JL, Rizer J, Vakkalanka JP, Rege SV, Holstege CP. Challenges in the diagnosis of acute cyanide poisoning. Clin Toxicol (Phila). 2018 Jul;56(7):609-617.
- Pruthi S, Shah S, Gambhir HS. Laundry Blues: a case of methemoglobinemia with laundry detergent and Tylenol ingestion. QJM. 2017 Sep 01;110(9):595-596.
- Zacarias CH, Esteban C, Rodrigues GL, Nascimento ES. Occupational exposure to hydrogen cyanide during large-scale cassava processing, in Alagoas State, Brazil. Cad Saude Publica. 2017 Jul 27;33(7):e00073416.
- Netto AB, Netto CM, Mahadevan A, Taly AB, Agadi JB. Tropical ataxic neuropathy – A century old enigma. Neurol India. 2016 Nov-Dec;64(6):1151-1159.
- Giebułtowicz J, Rużycka M, Wroczyński P, Purser DA, Stec AA. Analysis of fire deaths in Poland and influence of smoke toxicity. Forensic Sci Int. 2017 Aug;277:77-87.
- Hamad E, Babu K, Bebarta VS. Case Files of the University of Massachusetts Toxicology Fellowship: Does This Smoke Inhalation Victim Require Treatment with Cyanide Antidote? J Med Toxicol. 2016 Jun;12(2):192-8.
- Abraham P, et al. (2015). Sodium nitroprusside in intensive care medicine and issues of cyanide poisoning, cyanide poisoning prophylaxis, and thiocyanate poisoning. DOI:
- Amizet L, et al. (2011). Occupational cyanide poisoning. DOI:
- Binh Ly. (2015). Acute cyanide poisoning.
- Facts about cyanide. (n.d.).
- Fleming FF, et al. (2010). Nitrile-containing pharmaceuticals: Efficacious roles of the nitrile pharmacophore. DOI:
- Hamel J. (2011). A review of acute cyanide poisoning with a treatment update.
- Lee J, et al. (2009). Noninvasive in vivo monitoring of cyanide toxicity and treatment using diffuse optical spectroscopy in a rabbit model.
- National Research Council (US) Subcommittee on Acute Exposure Guideline Levels. (2002). Acute Exposure Guideline Levels for Selected Airborne Chemicals: Volume 2. Washington, D.C.: National Academies Press.
- Peddy SB, et al. (2006). Acute cyanide poisoning.
- Sachs C. (2007). Don’t overlook cyanide poisoning in smoke inhalation.
- Safety guideline: Sodium cyanide.
- Toxic substances portal – Cyanide. (2014).