Cyanide toxicity - drstrider

[ArchivalUser]

hi guys just came across this point..felt gud 1 so though of sharing

patient is a victim of recent smoke inhalation
which antidote is preferred for Cyanide toxicity??

a)sodium thiosulfate
b)sodium nitrite

[ArchivalUser]

ANSWER IS B SODIUM NITRITE

[ArchivalUser]

I agree with fieldbee - Give Nitrite first to convert Hb to 3+ so the CN- will bind to Hb rather than inhibit OxPhos - then give thiosulfate to remove CN- from the Hb.

[ArchivalUser]

as the pt is a victim of recent smoke inhalation,he is at risk of CO poisoning thus increase in carboxyHB..and on giving sodium nitrite methemogobin if formed which furthers reduces the oxygen binding to Hb..for this reason Sodium thiosulfate is prefered which forms thiocyanate

[ArchivalUser]

Thanks drstrider for a good question. Did you come across this question from Qbank? I feel that CN rather than CO poisoning poses the most imminent danger to the patient. Therefore, I would still reason that I should do everything possible to speed up removal of the CN as we both know is an inhibitor of oxphos. The fastest way to do that is to use the patient's blood to lock up the CN-, allowing for oxphos to continue.

I just feel like giving thiosulfate would be too slow at removing the CN-. Because the main thing that dictates survival in a patient is production of ATP. Plus, even if hemoglobin sats are down - you will still have Pa02 that can partially complement it.

Anyways, sorry to write so much. I enjoy educational talk. lol Let me know what you think. But, again, that is a really good question.