Is there any benefit to using sodium thiosulfate in addition to hydroxocobalamin when treating cyanide toxicity?
Clinicians were often reluctant to use all components of the old cyanide antidote kit in sick, unstable patients with possible cyanide toxicity for fear of inducing excessive methemoglobinemia or hypotension with sodium nitrite. In many of these cases, sodium thiosulfate was given alone. While sodium thiosulfate is relatively safe and effective, it has certain disadvantages as a cyanide antidote. For one thing, unlike HC, it does not directly detoxify cyanide. Rather, it works indirectly by supporting the body’s own primary detoxifying metabolic pathway, supplying sulfur that allows the enzyme rhodanase to convert cyanide to thiocyanate (Fig. 1.) In addition, thiosulfate does not readily penetrate into mitochondria, where the metabolism of cyanide takes place. The bottom line is that there is a delay between the administration of sodium thiosulfate and the onset of its antidotal action. The purpose of sodium nitrite in the old kit was to buy time until sodium thiosulfate could take eff
