Recognition and Treatment

Recognizing and Treating Industry Related Cyanide Poisoning

The following information provides general guidance and is not meant to substitute for industrial or medical policies, procedures or protocols.

In the case of industrial accidents, it is usually easy for rescue workers and other on-site personnel to identify from which containers the poisonous substance has come, and therefore appropriate medical interventions can begin immediately. Additionally, an almond-like odor may be detected in the air.

If cyanide poisoning is suspected, the victim should immediately be moved to an area with fresh air. Contaminated clothing should be removed, the skin immediately washed with soap and water and professional medical care should be sought as quickly as possible.

In the event of a spill or leak involving hydrogen cyanide, persons not wearing protective equipment and clothing should be restricted from contaminated areas until cleanup has been completed. The following steps should be undertaken following a spill or leak:

While extremely lethal at high concentrations, depending on the extent of the exposure and time to treatment, prompt treatment may result in complete recovery. Currently, cyanide poisoning can be treated with prompt administration of an approved antidote.

Below is a general approach to a suspected patient with a cyanide exposure in an industrial setting in the US:

• If the patient does not have symptoms - no treatment is necessary. Decontaminate the patient and observe carefully.
• If the patient is conscious, but has mild symptoms (such as nausea, mild shortness of breath, mild dizziness, mild anxiety) then 100% oxygen should be administered.
• If the patient's consciousness is impaired (including such symptoms as slurred speech, drowsiness, altered mental status), has unstable vital signs, is having seizures, or is in a coma, administer 100% oxygen and proceed to the antidote ASAP (under medical direction), beginning with amyl nitrite as a temporizing measure until sodium nitrite can be administered. Assisted ventilation may be needed.

Note: the use of a cyanide antidote in the absence of impaired consciousness, unstable vital signs, seizures and /or coma may not be warranted. However, assuring an IV access as soon as possible in cases where significant toxicity is possible, especially if toxicity may be delayed, is suggested.

Medical Interventions Approved in the United States

Medical professionals in the United States have access to an antidote called the Cyanide Antidote Kit, (also called the Taylor, Lilly or Pasadena Kit). This kit contains three different medicines - amyl nitrite, sodium nitrite and sodium thiosulfate - to be used in a specific sequence: the amyl nitrite is administered as an inhalant, followed by the sodium nitrite and sodium thiosulfate, which are given intravenously.

The nitrites are given to convert hemoglobin in the red blood cell to methemoglobin, which attracts the cyanide away from the cytochrome oxidase and allows the cell to continue the process of aerobic metabolism. Sodium thiosulfate is given to facilitate detoxification of cyanide by the body's own cyanide clearance system.

Learn more about aerobic metabolism

Medical Interventions in Other Parts of the World

In countries throughout the world, other antidotes have been developed and are currently used by emergency medical personnel in various situations.

Hydroxocobalamin, a precursor of vitamin B12, has been used safely and effectively in France (with the trade name Cyanokit®, made by Merck Santé S.A.S.) since 1996 to treat smoke inhalation victims for cyanide exposure, including as an empiric therapy and in cases of suspected cyanide poisoning. While not currently available in the United States, it is being investigated for possible use in the U.S. The mechanism of action of hydroxocobalamin is fairly straightforward. The hydroxocobalamin attaches to the cyanide directly, creating cyanocobalamin, a natural form of vitamin B12, which is excreted in the urine. The advantage of this approach is that methemoglobin is not produced and the oxygen-carrying capacity of the victim's blood is not lowered. Therefore, it is suitable for use in smoke inhalation victims as well as other causes of cyanide poisoning. The most common side effect of hydroxocobalamin is temporary pink discoloration of the skin, urine and mucous membranes.

Dicobalt Ededate is used in the UK to treat cyanide poisoning. Cobalt compounds fixate to the cyanide ion. One 300mg ampule is administered intravenously at a regular rate over one minute followed by 50ml glucose intravenous infusion. The most common side effects include vomiting, hypotension or hypertension, and tachycardia. Dicobalt edetate can be extremely toxic in the absence of cyanide ions and can only be given when the presence of severe cyanide poisoning is detected.

4-dimethylaminophenol (DMAP) is used in Germany as an antidote for severe cyanide poisoning in patients who are in a deep coma and who have dilated non-reactive pupils and deteriorating cardio-respiratory function. DMAP converts part of the hemoglobin of the blood from ferrous hemoglobin to ferric; this creates a pool of binding potential can divert cyanide from the cytochromes it posions. Patients are given an intravenous dose of 3.25 mg/kg body weight. There are differences in individual susceptibility, which may result in an unacceptably high level of methemoglobin after normal therapeutic doses. Adverse side effects include: hemolyisis, mild headache, dizziness, hyperventilation, cyanosis, and discoloration of the urine.