cyanide

cyanide

 [si´ah-nīd]

a binary compound containing the radical CN— (cyanogen); since cyanide prevents tissue use of oxygen, most of its compounds are deadly poisons. Some inorganic compounds, such as cyanide salts, potassium cyanide, and sodium cyanide, are important in industry for extracting gold and silver from their ores or in electroplating, and other cyanide compounds are used in manufacture of synthetic rubber and textiles or as pesticides.

cyanide poisoning poisoning by cyanide or one of its compounds; most cyanide compounds are deadly poisons. Characteristics include nausea without vomiting, dizziness, convulsions, opisthotonos, and death from respiratory paralysis.

Treatment varies according to the nature of the poison. In the case of swallowed poison like hydrocyanic acid, the poison itself will cause vomiting. If the victim is able to swallow, milk or water may be given. A large dose of hydrocyanic acid will cause almost instant death. If a gas such as hydrogen cyanide has been inhaled, the victim should be taken into open air and given artificial respiration. Sodium thiosulfate and sodium nitrate are used as antidotes to cyanide poisoning.

While poisoning may occur following exposure to any substance that releases cyanide ions, it can also occur concurrently if another toxic ion is present (for example, with mercuric cyanide). In such a situation, ironically the symptoms of toxicity may change to those of the second ion when the antidote to cyanide is used.

cy·a·nide

(sī'an-īd),

1. The radical -CN or ion (CN)^-. The ion is extremely poisonous, forming hydrocyanic acid in water; has the odor of almond oil; inhibits proper metabolism of oxygen through disruption of respiratory proteins (cytochromes) at the cellular level.

2. A salt of HCN or a cyano-containing molecule.

3. Often used as a shortened term to describe cyanide gas.

cyanide

A highly reactive compound (CN–) with a high affinity for metal ions (e.g., iron of cytochrome oxidase); in vivo, cyanide usually exists as a salt—e.g., hydrogen cyanide (HCN), potassium cyanide (KCN) and others. HCN is produced by the thermal decomposition of various nitrogen-containing compounds, either natural (e.g., wool and silk) or synthetic (e.g., polyurethane and polyacrylonitrile) It is one of the two principal toxic gases that cause death in fires (the other is carbon monoxide); ambient cyanide levels of > 500 ppm are lethal within 10 minutes.
 
Laboratory
The mean cyanide concentration of victims who died in fatal fires in one study was 116 µmol/L, and 22 µmol/L in those who lived; the serum T1⁄2 for HCN is one hour. The plasma lactate levels in those who died was 29 mmol/L; lactate levels correlate well with HCN levels and may serve as a surrogate marker.
 
Management
Various agents have been used to treat cyanide poisoning, in particular those that transform haemoglobin to methaemoglobin, which avidly binds cyanide. This manoeuvre is limited by the methaemoglobin’s ferric state (Fe3+), which cannot bind O2, and at levels of > 30% exacerbates the tissue hypoxia caused by the cyanides.

cyanide

Toxicology A reactive ion–CN– with a high affinity for metal ions–eg, iron of cytochrome oxidase; in vivo, cyanide usually exists as a salt–eg, hydrogen cyanide–HCN, KCN, etc Lab Mean cyanide concentration of victims who died in fatal fires in one study was 116 µmol/L, and 22 µmol/L in those who lived; serum T_1⁄2 for HCN is 1 hr; plasma lactate levels in those who died was 29 mmol/L; lactate levels correlate well with HCN levels and may serve as a surrogate marker Management Agents used to treat cyanide poisoning, include those that transform Hb to metHb, which avidly binds cyanide; this maneuver is limited by metHb's ferric state–Fe3+, which cannot bind O₂, and at > 30% exacerbates tissue hypoxia caused by the cyanides

cy·a·nide

(sī'ăn-īd)

1. The radical -CN or ion (CN-). The ion is extremely poisonous, forming hydrocyanic acid in water; inhibits respiratory enzymes.

2. A salt of HCN.

3. A molecule containing a cyanide group.

4. A class of toxic chemical-warfare agents.
See also: blood agent, hydrogen cyanide, cyanogen chloride

cyanide

any salt of hydrocyanic acid. Potassium cyanide (KCN) and hydrogen cyanide (HCN) are the commonest examples of cyanides, all of which are extremely poisonous. They combine with cytochrome enzymes (e.g. CYTOCHROME OXIDASE), which transfer hydrogen atoms in CELLULAR RESPIRATION, and thus block the production of energy in the cells.