sodium thiosulfate, sodium nitrite, and amyl nitrite (cyanide antidote kit): Dosing and Uses

Dosing and uses of Cyanide antidote kit (sodium thiosulfate, sodium nitrite, and amyl nitrite)

• Adult
• Pediatric

Adult dosage forms and strengths

Discontinued from United States market May 2012

per kit

• sodium thiosulfate injection: 12.5g/50mL (2 vials)
• sodium nitrite: 300mg/10mL (2 ampules)
• amyl nitrite inhalant: 0.3mL (12 ampules)

Cyanide Poisoning (Orphan)

Crush 0.3 mL ampul of amyl nitrite q1min and inhale vapor for 15-30 seconds until IV sodium nitrite infusion available

Following infusion of 300 mg or 10 mg/kg IV sodium nitrate, over 2-5 minutes, inject 12.5 g sodium thiosulfate IV over 10 minutes PRN; may repeat both injections at 1/2 original dose

Other Information

Vasopressors should be available to treat shock

Currently manufactured by Akorn, Inc, Buffalo Grove, IL (1-800-535-7155)

Many clinicians will administer only sodium thiosulfate portion if concerned of concomitant carboxyhemoglobinemia, or if ingestion is uncertain

Other Indications & Uses

Smoke inhalation with acidosis

Pediatric dosage forms and strengths

Discontinued from United States market May 2012

per kit

• sodium thiosulfate injection: 12.5g/50mL (2 vials)
• sodium nitrite: 300mg/10mL (2 ampules)
• amyl nitrite inhalant: 0.3mL (12 ampules)

Cyanide Poisoning

Administer amyl nitrite as in adults; crush 0.3 mL ampul of amyl nitrite q1min and inhale vapor for 15-30 seconds until IV sodium nitrite infusion available

Follow amyl nitrite administration with sodium nitrate 10 mg/kg (0.33 mL/kg or 6-8 mL/sq.meter of 3% solution; not to exceed 10 mL)

Inject sodium thiosulfate IV 7 g/sq.meter over 10 minutes; not to exceed 12.5 g; may repeat both injections at 1/2 original dose

Cyanide antidote kit (sodium thiosulfate, sodium nitrite, and amyl nitrite) adverse (side) effects

Frequency not defined

Precipitaiton of methemoglobinemia

Worsening hypoxia

Hypotension (sodium nitrite)

ADR's of nitrite Rx above include hypotension, tachycardia, HA, severe methemoglobinemia

Pharmacology of Cyanide antidote kit (sodium thiosulfate, sodium nitrite, and amyl nitrite)

Mechanism of action

Nitrites create methemoglobins to bind to cyanide

sodium thiosulfate

• Primary route of endogenous cyanide detoxification is by enzymatic transulfuration to thiocyanate (SCN-), which is relatively nontoxic and readily excreted in the urine
• Thought to serve as a sulfur donor in the reaction catalyzed by the enzyme rhodanese, thus enhancing the endogenous detoxification of cyanide

sodium nitrite and amyl nitrite

• Reacts with hemoglobin to form methemoglobin, an oxidized form of hemoglobin incapable of oxygen transport but with high affinity for cyanide
• Cyanide preferentially binds to methemoglobin over cytochrome a3, forming the nontoxic cyanomethemoglobin
• Vasodilation has also been cited to account for at least part of the therapeutic effect of amyl nitrite and sodium nitrite