Sodium nitrite and sodium thiosulfate is a combination medicine that is used as an antidote to cyanide poisoning. Sodium nitrite and sodium thiosulfate works by helping cells in the body convert cyanide to a form that can be removed from the body through urination. Sodium nitrite and sodium thiosulfate is used in an emergency to treat cyanide poisoning. This type of poisoning can occur if you are exposed to smoke from a house or industrial fire, if you swallow or breathe in cyanide, or if you get cyanide on your skin. Sodium nitrite and sodium thiosulfate may also be used for purposes not listed in this medication guide.