Sodium Thiosulfate

Sodium Thiosulfate is indicated for sequential use with sodium nitrite for treatment of acute cyanide poisoning that is judged to be life threatening. Use with caution if the diagnosis of cyanide poisoning is uncertain.

Sodium thiosulfate acts as an antidote in the treatment of cyanide poisoning. It acts as a sulphur-donating substrate for the enzyme rhodanese, thus speeding up the conversion of cyanide to thiocyanide, which is relatively non toxic. It is often used in combination with sodium nitrite but may be used alone in less severe poisoning.

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

Child: To be given after 4-10 mg/kg of sodium nitrite (max: 300 mg) has been admin: 400 mg/kg of sodium thiosulfate, as a 25 or 50% solution (max: 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 min at half the initial doses.

Formal drug interaction studies have not been conducted with Sodium Thiosulfate.

Osmotic disturbances. Oral: catharsis (at high doses).

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. Because Sodium Thiosulfate Injection may be administered in life-threatening situations, breast-feeding is not a contraindication to its use. Because many drugs are excreted in human milk, caution should be exercised following Sodium Thiosulfate Injection administration to a nursing woman. There are no data to determine when breastfeeding may be safely restarted following administration of sodium thiosulfate.

Sodium thiosulfate drug product may contain trace impurities of sodium sulfite. The presence of a trace amount of sulfites in this product should not deter administration of the drug for treatment of emergency situations, even if the patient is sulfite-sensitive.

Pediatric Use: There are case reports in the medical literature of sodium nitrite in conjunction with sodium thiosulfate being administered to pediatric patients with cyanide poisoning; however, there have been no clinical studies to evaluate the safety or efficacy of sodium thiosulfate in the pediatric population.

Geriatric Use: Sodium thiosulfate is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

There is limited information about the effects of large doses of sodium thiosulfate in humans. Oral administration of 3 g sodium thiosulfate per day for 1-2 weeks in humans resulted in reductions in room air arterial oxygen saturation to as low as 75%, which was due to a rightward shift in the oxygen hemoglobin dissociation curve. The subjects returned to baseline oxygen saturations 1 week after discontinuation of sodium thiosulfate. A single intravenous administration of 20 mL of 10% sodium thiosulfate reportedly did not change oxygen saturations.

Antidote preparations

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