Sodium thiosulfate, or sodium thiosulphate, is a colorless, water-soluble salt. It is a calcium-chelating agent and has many medical uses in removing toxic substances from the body. Depending on the medical condition being treated, the salt can be injected, taken orally, or applied to the skin. It is also used in some vital tests for kidney patients to glean information without doing harm.
This compound is combined with sodium nitrite and used as an antidote for cyanide poisoning in both children and adults. Sodium thiosulfate reacts with the cyanide and forms sodium thioyanate, a nontoxic substance that can then be excreted harmlessly from the body. The salt is also used to treat arsenic poisoning. Studies show that it can be useful in removing excess copper from patients too.
The calcium-chelating properties of sodium thiosulfate make it a useful agent for treating disorders involving excess calcium. Both tumoral calcinosis and calcific nephrolithiasis have been successfully treated with the salt. Studies indicate it may treat calciphylaxis, a condition that sometimes occurs in chronic kidney dialysis patients.
Ringworm and tinea versicolor are fungal infections of the skin. Ringworm looks like a circular area of rash, while tinea versicolor appears as white patches on the skin. Sodium thiosulfate is used to treat both of these fungal infections. It is added to the water of footbaths to treat ringworm of the feet. To treat tinea versicolor, the salt is often combined with salicylic acid in a preparation that is applied topically to the affected areas.
Chemotherapy agents often have unpleasant or unwanted side effects. Cisplatin, a chemotherapy drug, can cause hearing loss. Sodium thiosulfate is the only agent that has been shown to prevent or lessen this chemotherapy-induced hearing loss. Mechlorethamine, or nitrogen mustard, can sometimes cause problems at the injection site or leak into surrounding tissues. Sodium thiosulfate is a chemoprotective agent and neutralizes this cancer drug, minimizing the side effects that the leaking, or extravasation, causes.
The renal glomerular filtration rate is a useful indicator of renal function in kidney patients. The test measures a chemical that remains at a steady level in the patient’s bloodstream. Sodium thiosulfate can be used for the test, as the salt is not secreted or reabsorbed by the kidneys. The salt is first injected into the patient, then urine measurements are taken to gauge the amount of salt that was filtered and excreted.