Sodium Thiosulfate is indicated for sequential use with sodium nitrite in the treatment of acute cyanide poisoning that is considered life-threatening. It should be used with caution when the diagnosis of cyanide poisoning is uncertain.

Sodium thiosulfate acts as an antidote in cyanide poisoning. It works as a sulfur-donating substrate for the enzyme rhodanese, thereby accelerating the conversion of cyanide into thiocyanate, which is relatively non-toxic. It is commonly used in combination with sodium nitrite, but may also be used alone in cases of less severe poisoning.

Adult To be given after 300 mg of sodium nitrite has been administered over 5–20 minutes: 12.5 g of sodium thiosulfate (50 ml of a 25% solution or 25 ml of a 50% solution) given over 10 minutes. Methaemoglobin concentration should not exceed 30–40%. If symptoms of cyanide toxicity recur, the doses of nitrite and thiosulfate may be repeated after 30 minutes at half the initial doses.

Child To be given after 4–10 mg/kg of sodium nitrite (maximum: 300 mg) has been administered: 400 mg/kg of sodium thiosulfate, as a 25% or 50% solution (maximum: 12.5 g). Methaemoglobin concentration should not exceed 30–40%. If symptoms of cyanide toxicity recur, the doses of nitrite and thiosulfate may be repeated after 30 minutes at half the initial doses.

No well-controlled drug interaction studies have been conducted with sodium thiosulfate.

Osmotic disturbances may occur. When taken orally at high doses, catharsis (severe laxative effect) may be seen.

Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. Sodium Thiosulfate Injection should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is not known whether sodium thiosulfate is excreted in human milk. Since it may be used in life-threatening situations, breastfeeding is not a contraindication. However, caution should be exercised when administering it to nursing mothers. There is no available data on when breastfeeding can be safely resumed after administration.

Sodium thiosulfate products may contain trace amounts of sodium sulfite. The presence of sulfites should not prevent its use in emergency situations, even in sulfite-sensitive patients.

Pediatric Use: Limited case reports describe use with sodium nitrite in pediatric cyanide poisoning. However, no clinical studies have established safety or efficacy in children.

Geriatric Use: The drug is primarily excreted by the kidneys. Elderly patients are more likely to have reduced renal function, increasing the risk of adverse effects. Dose selection should be cautious, and renal function monitoring may be useful.

Limited data are available on overdose in humans. Oral administration of 3 g daily for 1–2 weeks has caused reduced arterial oxygen saturation (as low as 75%) due to a rightward shift of the oxygen–hemoglobin dissociation curve. Levels returned to normal within one week after stopping the drug. A single IV dose of 20 mL of 10% sodium thiosulfate did not significantly affect oxygen saturation.

Antidote preparations

Store at controlled room temperature between 20°C and 25°C. Protect from direct light. Do not freeze.