Effects of cyanide antidotes used with sodium nitroprusside infusions: sodium thiosulphate and hydroxocobalamin given prophylactically to dogs
Krapez, J.R.; Vesey, C.J.; Adams, L.; Cole, P.V.
British Journal of Anaesthesia 53(8): 793-804
1981
ISSN/ISBN: 0007-0912 PMID: 7272142 Document Number: 170096
Cyanide antidotes were given to dogs before an infusion of sodium nitroprusside 1.5 mg/kg for 1 h. Dogs given thiosulfate 75 mg/kg had significantly lower plasma and red cell cyanide concentrations while plasma thiocyanate concentrations were significantly increased compared with controls. These changes were associated with minimal disturbance of tissue oxygenation. There was no effect on red cell cyanide for thiocyanate concentrations in dogs treated with hydroxocobalamin 1.5 mg/kg but plasma cyanide concentrations were significantly greater than in those receiving no antidote although there was less evidence of impaired oxygenation. There was no evidence of a synergistic action between thiosulfate and hydroxocobalamin. The vascular response to nitroprusside was unchanged in the thiosulfate-treated dogs but was significantly greater in those given hydroxocobalamin. The implications for prophylaxis and treatment of cyanide poisoning following nitroprusside overdose were discussed.