What is the treatment for cyanide poisoning?

Treatment of Cyanide Poisoning

Hydroxocobalamin is the first-line treatment for cyanide poisoning due to its efficacy and favorable safety profile, with sodium nitrite recommended when hydroxocobalamin is unavailable. 1

First-Line Treatment Algorithm

• Administer hydroxocobalamin immediately for suspected cyanide poisoning 1

  • Adult dose: 5 g IV (10 g for cardiac arrest) 1
  • Pediatric dose: 70 mg/kg (maximum 5 g) 1

• When hydroxocobalamin is unavailable, administer sodium nitrite 1, 2

  • Use with caution in patients with smoke inhalation due to risk of worsening oxygen-carrying capacity 2
  • Precise dosing is required in children and anemic patients to avoid excessive methemoglobin formation 1

• Administer sodium thiosulfate in addition to hydroxocobalamin or sodium nitrite to enhance cyanide elimination 1

  • Sodium thiosulfate alone acts too slowly to be considered monotherapy in life-threatening poisoning 1

• Provide 100% oxygen therapy regardless of oxygen saturation 1

  • Oxygen counteracts cyanide's action at the mitochondrial level 3, 4

Clinical Recognition of Cyanide Poisoning

• Look for these key clinical manifestations 2:

  • Altered mental status (confusion, disorientation, coma)
  • Cardiovascular collapse
  • Metabolic acidosis with elevated lactate
  • Seizures
  • Mydriasis (pupillary dilation)

• Laboratory findings highly suggestive of cyanide poisoning 2, 3:

  • Plasma lactate ≥ 8 mmol/L in pure cyanide poisoning
  • Plasma lactate ≥ 10 mmol/L in smoke inhalation victims

Special Considerations

• For smoke inhalation victims 1:

  • Assess for exposure to fire in enclosed area
  • Look for soot around mouth, nose, or oropharynx
  • Evaluate for altered mental status
  • Hydroxocobalamin is preferred over sodium nitrite due to potential concurrent carbon monoxide poisoning 1, 3, 5

• Do not delay treatment to obtain confirmatory testing 2

  • No widely available, rapid confirmatory cyanide blood test exists
  • Treatment decisions must be based on clinical presentation

Supportive Care

• Provide immediate airway, ventilatory, and circulatory support 6, 2

  • Do not delay these interventions to administer antidotes
  • Correct acidosis and support blood pressure as needed 4, 7

• Contact regional poison control center (1-800-222-1222) for expert guidance 2

Important Caveats

• Hydroxocobalamin is preferred over sodium nitrite in patients with:

  • Smoke inhalation (due to concurrent carbon monoxide exposure) 1, 3, 5
  • Hypotension (sodium nitrite can worsen hypotension) 2, 5
  • Anemia (sodium nitrite reduces oxygen-carrying capacity) 2

• Sodium nitrite requires careful dosing to avoid excessive methemoglobin formation, especially in children and anemic patients 1, 2, 7

• The safety of administering multiple different cyanide antidotes simultaneously has not been established 2