The Pre-brief
A 32-year-old female presents to the trauma bay after a house fire. She is found to be severely mentally altered but no clear evidence of burns. An antidote is administered and shortly after, you notice her urine is dark red.
Did something go wrong??
Introduction
Patients at risk for cyanide toxicity are those who present after being exposed to fire smoke in an enclosed area, may have soot present around the mouth, nose, and/or oropharynx, and have altered mental status. If a patient has suspected cyanide toxicity from smoke inhalation, they may benefit from hydroxycobalamin.
The two most common inhalational toxicants found in smoke are carbon monoxide and hydrogen cyanide. Both gases are cellular asphyxiants. It is thought that the amount of hydrogen cyanide in fire related smoke has increased over the decades due to increases in synthetic building and furnishing materials. Grabowska and colleagues learned that cyanide is detectable in the blood in ~60% of fire related fatalities and 50% of survivors of enclosed space fires.
Hydroxycobalamin is a synthetic injectable form of vitamin B12 and contains cobalt. Cobalt binds to cyanide and detoxifies it, making it an ideal antidote. The initial adult dose is 5 g given as an infusion over 15 minutes. Repeat dosing of 5 g, with a maximum cumulative dose of 10 g may be considered in severe poisonings. The initial pediatric dose is 70 mg/kg as a single infusion (max 5,000 mg/dose). Repeat dosing of 70 mg/kg (max 5,000 mg/dose) may be considered in severe poisonings. Dosing for cyanide toxicity is 2 million times the recommended daily intake of vitamin B12 (cyanocobalamin) and 5,000 times the therapeutic dose for treatment in pernicious anemia.
Cyanokit®
Contains:
- 1 vial of hydroxycobalamin for injection 5 g
- 1 intravenous administration set
- 1 transfer spike
- 1 quick use reference guide
- 1 package insert
Instructions for Use:
- Add 200 mL of 0.9% sodium chloride to the hydroxycobalamin 5 g injection vial using the provided transfer spike.
- If sodium chloride is not readily available, it may be mixed with lactated ringers or Dextrose 5%.
- The vial should be repeatedly inverted or rocked for at least 60 seconds prior to infusion. DO NOT SHAKE
- Contents should be dark red
- Use the provided vented intravenous tubing to hang the medication and infuse over 15 minutes
- May repeat a second 5 g dose up to a total max dose of 10 g
Adverse Events:
Hydroxycobalamin WILL cause a deep red discoloration in the urine, mucous membranes and skin, which can last up to 5 weeks after administration because it is red in color. It is harmless and therapy should not be discontinued because of it. Other adverse events include hypertension and interference with lab parameters.
The Debrief
- Patients presenting with altered mental status or soot around the mouth, nose or oropharynx, after being exposed to fire smoke in an enclosed area may benefit from hydroxycobalamin.
- Hydroxycobalamin is dosed as 5 g over 15 minutes. A second dose may be administered up to a max of 10 g.
- Hydroxycobalamin will cause urine discoloration which can last up to 5 weeks, however is not harmful and should not result in therapy discontinuation.
References
- Thompson JP, Marrs TC. Hydroxocobalamin in cyanide poisoning. Clin Toxicol (Phila). 2012;50(10):875-885. doi:10.3109/15563650.2012.742197
- 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;12(2):192-198. doi:10.1007/s13181-016-0533-0
- Cyanokit® [package insert]. Semoy, France. Meridian Medical Technologies. June 2020
