“Sodium Nitrite suicide kit poisoning, methemoglobinemia and methylene blue” From EMC’s Quick Hits 26 With Additional Resources

In addition to this post, please see the following resources from medscape:

• methylene blue (Rx)
  Brand and Other Names: Provayblue
  Classes: Antidotes, Other
  • Black Box Warnings
    • May cause serious or fatal serotonergic syndrome when coadministered with serotonergic drugs
    • Avoid coadministration with SSRIs, SNRIs, and MAOIs
  • Administration
• Methemoglobinemia
  Updated: Dec 21, 2020
  Author: Mary Denshaw-Burke, MD, FACP

In this post I excerpt “Sodium Nitrite suicide kit poisoning, methemoglobinemia and methylene blue” from EM Quick Hits 26 LAST, Sodium Nitrite Poisoning, Post-intubation Care, Tetracaine for Corneal Abrasion, ST Segment in Occlusion MI, Coping with COVID. [Link is to the podcast and show notes.] Published February 2021. This segment of the podcast is from 10:51 to 17:58.

Here is the excerpt:

Sodium Nitrite suicide kit poisoning, methemoglobinemia and methylene blue

1. Sodium nitrite (a yellow-white crystalline powder food preservative/additive) “suicide kits” can be purchased online resulting in ED presentations with massive overdose
2. Sodium nitrite causes toxicity through smooth muscle relaxation resulting in vasodilalatory shock and by producing methemoglobin, shifting the oxygen-Hb dissociation curve to the left resulting in cyanosis, low oxygen saturation despite maintained respiratory status and chocolate brown coloured blood
3. Workup includes co-oximetry for methemoglobin on a VBG or AGB; methemoglobin is normally <1.5% in healthy individuals; >10% methemoglobin results in cyanosis, >20% results in headache, dizziness, nausea and >50% results in tissue ischemia with seizures, dysrhythmias, acidosis
4. For intentional suicide attempts of sodium nitrite suggested dosing is IV Methylene blue 2mg/kg push, repeated if methemoglobin level has not decreased at 15 minutes to a maximum of 7mg/kg and consideration for red cell or exchange transfusions

Reference List:

1. Durão C, Pedrosa F, Dinis-Oliveira RJ. A fatal case by a suicide kit containing sodium nitrite ordered on the internet. J Forensic Leg Med. 2020 Jul;73:101989. doi: 10.1016/j.jflm.2020.101989. Epub 2020 Jun 2.
2. Dean, D.E., Looman, K.B. and Topmiller, R.G. (2021), Fatal methemoglobinemia in three suicidal sodium nitrite poisonings. J Forensic Sci. https://doi.org/10.1111/1556-4029.14689
3. Katabami, K., Hayakawa, M., & Gando, S. (2016). Severe Methemoglobinemia due to sodium nitrite poisoning. Case Reports in Emergency Medicine, 2016, 1-3. https://doi.org/10.1155/2016/9013816