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Antidotes & Toxicology Pregnancy: Limited data in pregnancy; as a precautionary measure, it is preferable to avoid use during pregnancy. Breast-feeding should be discontinued during treatment.

Sodium Thiosulfate

Brand names: Sodium Thiosulfate Injection

Sodium thiosulfate is an intravenous antidote used in the emergency management of cyanide poisoning, typically alongside or following other cyanide antidotes.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 50 mL (12.5 g) IV
Route: Intravenous (slow IV injection)
Frequency: Single dose at 5 mL/minute, immediately following sodium nitrite (or hydroxocobalamin)
Max: 50 mL (12.5 g) - one vial (250 mg/mL)
For acute life-threatening cyanide poisoning, adjunctive to airway, ventilatory and circulatory support. Adults: give after 10 mL (300 mg) sodium nitrite at 2.5-5 mL/min, then 50 mL (12.5 g) sodium thiosulfate at 5 mL/min; alternatively after 5 g hydroxocobalamin IV over 15 minutes. Elderly (65 years and over): no specific dose adjustment required. Repeat: if no treatment response within 30-60 minutes or if signs of poisoning reappear, repeat after 30 minutes using one-half the original dose of both sodium nitrite and sodium thiosulfate. Blood pressure must be monitored; decrease the rate if significant hypotension occurs. Each 12.5 g dose contains approximately 3.6 g of sodium.

Paediatric dose

Dose: 250 mg/kg
Route: Intravenous (slow IV injection)
Frequency: Single dose, immediately following sodium nitrite (or hydroxocobalamin)
Max: 50 mL (12.5 g)
Infants to adolescents (0-18 years): 1 mL/kg (250 mg/kg or approximately 30-40 mL/m2 BSA), not to exceed 50 mL total. Given immediately after sodium nitrite 0.2 mL/kg (6 mg/kg, max 10 mL) or hydroxocobalamin 70 mg/kg (max 5 g). Verify against a children's formulary.

Dose adjustments

Renal

No dose adjustment required in renal or hepatic impairment (administered as emergency therapy in an acute, life-threatening situation only).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Infants to adolescents (0-18 years): 1 mL/kg (250 mg/kg or approximately 30-40 mL/m2 BSA), not to exceed 50 mL total. Given immediately after sodium nitrite 0.2 mL/kg (6 mg/kg, max 10 mL) or hydroxocobalamin 70 mg/kg (max 5 g). Verify against a children's formulary.

Verify in a children's formulary

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients

Side effects

  • Hypotension
  • Headache, disorientation
  • Nausea, vomiting
  • Prolonged bleeding time
  • Salty taste in mouth, warm sensation over body

Clinical monograph

How it works

It acts as a sulphur donor for the enzyme rhodanese, which converts cyanide to the far less toxic thiocyanate that is then excreted renally.

Prescribing in practice

  • In acute cyanide poisoning it is given as part of an antidote strategy and should not delay other resuscitative measures or first-line antidotes such as hydroxocobalamin where available.
  • It is also used to reduce nephrotoxicity in certain chemotherapy regimens and in the management of calciphylaxis, reflecting its sulphur-donor properties.
  • Onset of effect is relatively slow, so it is often combined with a faster-acting agent in life-threatening cyanide toxicity.

Monitoring

Monitor airway, breathing, circulation, conscious level and lactate during treatment of suspected cyanide poisoning, with response to antidote therapy.

Counselling the patient

  • An antidote given by injection to treat cyanide poisoning.
  • Team: use as part of a structured cyanide poisoning protocol, not in isolation.
  • Continue supportive resuscitation alongside antidote administration.

Evidence & guidelines

Sodium thiosulfate is a recognised cyanide antidote in UK toxicology guidance (TOXBASE) and the SPC, used as part of combination antidote therapy.

Reference: NPIS Toxbase; Clinical Toxicology 2007; 45(3):271-277; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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Featured in these MRCEM clinical pathways

Sodium Thiosulfate is a core drug in the following exam-focused workups on our sister siteReviseMRCEM.

MRCEM Primary / Intermediate / OSCE candidates: each pathway includes exam-style questions, RCEM/NICE citations, and FAQ summaries.