Most common exposure d/t fire and has toxicity in minutes

Reversible binder of terminal e- acceptor in transport chain -> decreased ATP -> coma + CV collapse

Management

Consider in all fire/CO poisoned patients:

• Unresponsive/arrested patients – empiric treatment
• If altered/semi-responsive – empiric treatment if lactate elevated (e.g. >8)

Treatment

Cyanokit: Hydroxycobalamin 5 g IV – may repeat x 1 if needed

• Combines with cyanide to make B12 which is then cleared renally

Combo antidote: Cheaper, so many places still have this

• Sodium thiosulfate – replenishes sulfur for function of endogenous (rhodanese) enzyme that detoxifies cyanide
• Na Nitrite – Forms methemoglobin which binds cyanide – should get you to methemoglobin level around 40%
  • Concurrent CO poisoning is a relative contraindication but if this is all you have and very concerned for cyanide poisoning should still give
• Amyl nitrite – Older kits have this, inhalational route, also creates methemoglobin