Usual Adult Dose for Cyanide Poisoning

Sodium Nitrite: 300 mg (10 mL) intravenously (IV) at a rate of 2.5 to 5 mL/minute
Sodium Thiosulfate: 12.5 grams (50 mL), slow IV, immediately following sodium nitrite administration

• If signs of cyanide poisoning reappear, repeat treatment using one-half of the original dose of both sodium nitrite and sodium thiosulfate.

• Use with caution if the diagnosis of cyanide poisoning is uncertain.
• If clinical suspicion of cyanide poisoning is high, administer without delay and in conjunction with appropriate airway, ventilatory, and circulatory support.
• Expert advice from a regional poison control center may be obtained by calling 1-800-222-1222.

Usual Pediatric Dose for Cyanide Poisoning

Sodium Nitrite: 0.2 mL/kg (6 mg/kg or 6 to 8 mL/m2 BSA) intravenously (IV) at a rate of 2.5 to 5 mL/minute
Maximum dose: 300 mg (10 mL)
Sodium Thiosulfate: 250 mg/kg (1 mL/kg or approximately 30 to 40 mL/m2 BSA), slow IV, immediately following sodium nitrite administration
Maximum dose: 12.5 grams (50 mL)

• If signs of cyanide poisoning reappear, repeat treatment using one-half of the original dose of both sodium nitrite and sodium thiosulfate.

• Use with caution if the diagnosis of cyanide poisoning is uncertain.
• If clinical suspicion of cyanide poisoning is high, administer without delay and in conjunction with appropriate airway, ventilatory, and circulatory support.
• Expert advice from a regional poison control center may be obtained by calling 1-800-222-1222.
• Use with caution in patients under 6 months old; the presence of fetal hemoglobin, which is oxidized to methemoglobin more easily than adult hemoglobin, along with lower methemoglobin reductase levels compared to older patients, makes these patients at higher risk of developing severe methemoglobinemia compared to older patients.
• Mortality attributed to sodium nitrite was reported in a 17 month old child after administration of an adult dose (300 mg IV followed by a second dose of 150 mg).

Renal Dose Adjustments

Data not available

• Sodium nitrite and sodium thiosulfate are substantially excreted by the kidney.
• The risk of toxic reactions is greater in patients with impaired renal function.

Liver Dose Adjustments

Data not available

Precautions

US BOXED WARNING(S):
LIFE THREATENING HYPOTENSION AND METHEMOGLOBIN FORMATION

• Sodium nitrite can cause serious adverse events and death, even at doses less than twice the recommended therapeutic dose.
• Sodium nitrite causes hypotension and methemoglobin formation, which diminished oxygen carrying capacity.
• Hypotension and methemoglobin formation can occur concomitantly or separately.
• Because of these risks, use this product for life-threatening cyanide poisoning; use with caution if the diagnosis of cyanide poisoning is uncertain.
• Closely monitor patients during treatment to ensure adequate perfusion and oxygenation.
• Consider alternative therapeutic approaches in patients with known diminished oxygen or cardiovascular reserve (e.g. smoke inhalation victims, pre-existing anemia, cardiac or respiratory compromise), and those at higher risk of developing methemoglobinemia (e.g. congenital methemoglobin reductase deficiency), as they are at greater risk of life-threatening adverse events with this drug.

Dialysis

Data not available

Other Comments

Administration advice:

• Administering sodium nitrite to achieve an arbitrary level of methemoglobinemia may be unnecessary and potentially hazardous.
• Sodium nitrite's therapeutic effect does not appear to be mediated by methemoglobin alone; clinical responses have been reported with methemoglobin levels of less than 10%.
• Administration of sodium nitrite beyond the initial dose should be guided by clinical response to treatment; a second dose should only be considered for inadequate clinical response to the first dose.

• This drug is incompatible with hydroxocobalamin; do not administer via the same intravenous line.
• Simultaneous administration with blood products (whole blood, packed red cells, platelet concentrate, fresh frozen plasma) through the same intravenous line is not recommended, but they can be administered simultaneously through separate lines, preferably on contralateral extremities.

• Blood pressure must be monitored during treatment.
• Monitor patients for at least 24 to 48 hours after administration for adequacy of oxygenations and perfusion, and for recurrent signs and symptoms of cyanide toxicity.
• When possible, obtain hemoglobin/hematocrit at treatment initiation.
• Measuring oxygen saturation using standard pulse oximetry and calculated oxygen saturation values based on measures PO2 are unreliable in the presence of methemoglobinemia.
• It is recommended to monitor methemoglobin levels during treatment using co-oximetry; discontinue sodium nitrite if methemoglobin levels exceed 30%.
• Intravenous methylene blue and exchange transfusion have been reported in the literature as treatments for life-threatening methemoglobinemia.