![]() The high efficacy of thiosulfate may be attributed to its rhodanese catalyzed, direct binding to free blood cyanide, leading thus to its dissociation from cytochrome oxidase. Prevention of methemoglobin forming with toluidine blue did not affect the reactivating ability of nitrite or DMAP, thus suggesting more complex protective mechanisms then simple methemoglobin formation. When antidotes were applied 30 min after 20 mg/kg of cyanide, marked reactivation of cytochrome oxidase activity was observed with all antidotes (particularly with thiosulfate) except for phentolamine which had no effect. However, maximum inhibition was also 40%. In animals artificially ventilated with room air, observation was possible up to 60 min. Further observation was impossible because of rapidly lethal effects of cyanide. Pronounced dose-dependence was observed in the inhibition of the enzyme, at this relatively low, but lethal dose. injection of 1.3 LD50 (12 mg/kg) of cyanide. The course of inhibition was time-dependent and a peak of 40% was attained between 15 and 20 min after the s.c. The in vivo effects of sodium cyanide and its antidotes, sodium nitrite, sodium thiosulfate and 4-dimethylaminophenol (DMAP), as well as the alpha-adrenergic blocking agent phentolamine, on rat brain cytochrome oxidase were studied. Antidotal effect of sodium thiosulfate in mice exposed to acrylonitrile. The data indicate a marked protective effect of STS either before or after ACN exposure and this STS-induced antidotal response does not involve GSH in the brain. The levels of NPSH were significantly lowered by ACN in the liver (45% of the control), and kidneys (51% of the control), whereas in the brain NPSH levels were least affected and decreased modestly (85% of the control) following either acute or chronic administration of acrylonitrile. Non-protein sulfhydryl (NPSH) concentration was determined in the brain, kidneys, and liver of the mice exposed to a single or multiple doses of STS and ACN. Similar data was observed when STS was administered 10 and 30 minutes after ACN administration. All mice appeared normal after prophylactic treatment with STS and showed no ill effects from ACN exposure. Treatment with an IP injection of 400 mg/kg of STS from 10 to 30 minutes before ACN administration protected animals from ACN-induced lethality. Since sodium thiosulfate (STS) is both an effective cyanide antidote and neutralizing agent capable of binding to reactive chemicals or metabolites, its antidotal role was investigated in mice exposed to 60 mg/kg intraperitoneal (IP) ACN injection. Many have suggested that ACN or its reactive metabolite acts directly at the target tissues, while others have implicated the release of CN ions from the parent compound as the toxic moiety. Sodium thiosulfate Mechanism of actionĪlthough acute acrylonitrile (ACN) toxicity is very profound, the mechanism of its toxicity and immediate lethality is unclear. Evidence-based medicine for Chemical Defense - including efficacy and safety A. Sodium thiosulfate can be used for treatment of acute cyanide poisoning in combination with sodium nitrite. ![]() Chemical Defense therapeutic area(s) - including key possible uses ![]() Name of Chemical Defense therapeutic agent/device If needed, a second dose (half of the initial dose) may be administered.1. ![]()
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