What is the usual dose of Cyanokit (hydroxocobalamin) for treating cyanide poisoning?

Hydroxocobalamin (Cyanokit) Dosing for Cyanide Poisoning

The recommended initial dose of hydroxocobalamin (Cyanokit) for treating cyanide poisoning is 5 g administered intravenously for adults, with a second 5 g dose (total 10 g) for severe cases or cardiac arrest; for children, the dose is 70 mg/kg (maximum 5 g). 1

Adult Dosing

• Initial dose: 5 g IV 2, 1
• Second dose: Additional 5 g (total 10 g) for:
  • Cardiac arrest 1
  • Severe poisoning 1
  • Blood cyanide levels >40 μmol/L 1, 3

Pediatric Dosing

• Initial dose: 70 mg/kg IV (maximum 5 g) 1
• Particularly important for children with smoke inhalation showing:
  • Moderate poisoning: GCS score 13, confusion, stridor, hoarse voice, respiratory distress 1
  • Severe poisoning: GCS score ≤8, seizures, coma, mydriasis, hemodynamic instability 1

Administration Considerations

• Administer as soon as possible after suspected exposure 1
• The American Heart Association strongly recommends hydroxocobalamin as the first-line treatment for cyanide poisoning 2
• Consider sodium thiosulfate as an adjunctive treatment to enhance cyanide elimination 2, 1
• Administer 100% oxygen alongside antidote therapy 2, 1

Clinical Indications for Treatment

• Smoke inhalation with high suspicion of cyanide poisoning 1
• Signs of severe poisoning: cardiac/respiratory arrest, shock, coma 1
• Elevated plasma lactate (≥8 mmol/L) strongly correlates with cyanide poisoning 1
• Rapid onset of cardiovascular collapse, metabolic acidosis, depressed mental status, seizures 2

Efficacy and Safety

• Hydroxocobalamin has demonstrated efficacy in treating severe cyanide poisoning with survival rates of 71% in patients with blood cyanide exceeding lethal thresholds 4
• Common adverse effects include chromaturia (red-colored urine) and pink skin discoloration 4, 5
• Rare adverse effects may include dyspnea, facial edema, and urticaria 6
• Laboratory interference may occur due to the red color of hydroxocobalamin 1

Important Clinical Pearls

• A single 5 g dose appears capable of binding cyanide ions up to blood concentrations of approximately 40 μmol/L 3
• For concentrations above 40 μmol/L, additional hydroxocobalamin is necessary 3
• Combination therapy with sodium thiosulfate may provide synergistic effects through different mechanisms of action 7
• Hydroxocobalamin is preferred over sodium nitrite in patients with smoke inhalation due to potential carbon monoxide co-exposure 2

Remember that rapid administration is critical in cyanide poisoning as it can quickly lead to death if untreated. The favorable safety profile of hydroxocobalamin makes it appropriate to administer when cyanide poisoning is suspected, even before confirmation.