Action and Spectrum

Actions and spectrum: 

sodium thiosulfate is a sulfur-containing compound that reacts with cyanide to form thiocyanate, which is then excreted in the urine. sodium nitrite works by converting hemoglobin in red blood cells to methemoglobin, which has a higher affinity for cyanide than hemoglobin.

This allows methemoglobin to bind to cyanide, preventing it from binding to and inhibiting cytochrome oxidase in the mitochondria of cells, which is what causes the symptoms of cyanide poisoning. 

The combination of sodium thiosulfate & sodium nitrite is used to treat cyanide poisoning in situations such as smoke inhalation from fires, industrial accidents, and exposure to certain chemicals. 

Drug Interaction

Adverse Reaction

Frequency not defined 

sodium thiosulfate 

• Headache 
• Nausea/vomiting 
• Prolonged bleeding time 
• Hypotension 
• Disorientation 
• Salty taste 
• Warmth 

sodium nitrite 

• Hypotension 
• Palpitations 
• Dyspnea 
• Methemoglobinemia 
• Dizziness 
• Blurred vision 
• Confusion 
• Syncope 
• Tachycardia 
• Diaphoresis 
• Dysrhythmia 
• Headache 
• Tachypnea 
• Seizures 
• Coma 

Black Box Warning

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

sodium thiosulfate & sodium nitrite combination is contraindicated in patients with known hypersensitivity to either component or other nitrites. It should also not be administered to patients with severe anemia, hypotension, or respiratory depression. Additionally, it is contraindicated in patients who have received phosphodiesterase inhibitors within the last 24 hours.  

Caution: 

• Hypotension: sodium nitrite can cause a sudden drop in blood pressure, leading to hypotension.  
• Methemoglobinemia: sodium nitrite can cause methemoglobinemia, a condition where the oxygen-carrying capacity of blood is decreased. This can cause cyanosis and hypoxia. 
• Renal impairment: sodium thiosulfate is excreted primarily by the kidneys. Patients with renal impairment may have reduced clearance of sodium thiosulfate, leading to an increased risk of adverse effects. 
• Allergy: Patients who are allergic to sodium thiosulfate or sodium nitrite should not receive this antidote. 
• Interactions: sodium thiosulfate and sodium nitrite may interact with other medications, including those used to treat hypertension or erectile dysfunction.

Comorbidities: 

There are no specific comorbidities associated with the use of sodium thiosulfate and sodium nitrite. However, caution should be exercised in patients with a history of allergies or sensitivities to the medications or their components. Additionally, patients with underlying cardiac or pulmonary conditions may be at higher risk for adverse reactions during the administration of sodium nitrite. 

Pregnancy / Lactation

Pregnancy consideration: N/A 

Lactation: N/A  

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• <b>Category B: There is no evidence of risk to the fetus found in animal reproduction studies and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for an effect in humans, care must be taken for potential risks in pregnant women. 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite potential risks may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits These category drugs should be prohibited for pregnant women. 
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

sodium thiosulfate: When administered, sodium thiosulfate reacts with cyanide to form thiocyanate, which is then excreted in the urine. This reaction occurs rapidly and reduces the amount of cyanide in the body. 

sodium nitrite: sodium nitrite works by converting hemoglobin in the blood to methemoglobin, which has a higher affinity for cyanide than hemoglobin does. This allows methemoglobin to bind with the cyanide and remove it from circulation. 

Together, these two drugs work synergistically to treat cyanide poisoning by reducing the amount of cyanide in the body and binding any remaining cyanide to methemoglobin for excretion.  

Pharmacodynamics: 

sodium thiosulfate is a sulfur donor that promotes the detoxification of cyanide by the rhodanese enzyme, which catalyses the conversion of cyanide into thiocyanate, a less toxic compound that is excreted in urine. sodium nitrite, on the other hand, produces methemoglobin, a form of hemoglobin that binds cyanide with high affinity to form cyanomethemoglobin, which is then excreted in urine. Together, sodium thiosulfate and sodium nitrite form a complementary and synergistic mechanism of action to treat cyanide poisoning.  

Pharmacokinetics: 

sodium thiosulfate: 

• Absorption: sodium thiosulfate is not absorbed orally, and it is typically administered intravenously or intramuscularly. 
• Distribution: After intravenous or intramuscular administration, sodium thiosulfate is rapidly distributed throughout the extracellular fluid. 
• Metabolism: sodium thiosulfate is not metabolized and is primarily eliminated unchanged in the urine. 
• Elimination and excretion: The elimination half-life of sodium thiosulfate is about 12 hours, and it is primarily excreted unchanged in the urine. 

sodium nitrite: 

• Absorption: sodium nitrite is rapidly absorbed after oral, intravenous, or inhalation administration. 
• Distribution: sodium nitrite is widely distributed throughout the body and is highly protein-bound in the plasma. 
• Metabolism: sodium nitrite is metabolized in the body to nitric oxide (NO) and other metabolites, which play a role in its pharmacological effects. 
• Elimination and excretion: The elimination half-life of sodium nitrite is 30-60 minutes, and it is primarily excreted in the urine. 

Adminstartion

Administration: 

sodium thiosulfate is available as an injection, which is administered intravenously (IV) by a healthcare professional. sodium nitrite is also available as an injection, which is administered intravenously by a healthcare professional.

The dosing and administration of these drugs depend on the specific condition being treated, the patient’s age, weight, and medical history, as well as other factors. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: sodium thiosulfate & sodium nitrite 

Pronounced: [SOO-de-um-THYE-oh-SUL-fate-and-SOO-dee-um-NYE-trite]  

Why do we use sodium thiosulfate & sodium nitrite? 

sodium thiosulfate and sodium nitrite are used together as an antidote for cyanide poisoning. They work by converting cyanide to less toxic substances that can be eliminated from the body. This treatment is used in emergency situations where a person has been exposed to cyanide, such as in industrial accidents or chemical warfare.

sodium thiosulfate can also be used in the treatment of certain medical conditions, such as calciphylaxis (a rare disease that causes calcium deposits in the skin and soft tissues) and as an adjunct treatment for cisplatin-induced ototoxicity (hearing loss caused by chemotherapy).