Abstract: AIM: To study the antidotal effect of Nacetylcysteine(NAC) on acute poisoning with sodium cyanide(NaCN).METHODS: After intraperitoneal (ip)injected of four sulphydryl compounds respectively,the mice which were acutely poisoned by NaCN were observed of the behavioral change,convulsion number and mortality rate(within 72 h).The median lethal dose (LD₅₀) of acutely poisoned mice was detected in NaCN grouPand NAC protection group.1 min after mice were poisoned by NaCN,the mice were divided into three groups:the first was iPnormal saline (NS),the second was iPNAC in combination with sodium thiosulfate (Na₂S₂O₃),the third was iPsodium nitrite (NaNO₂) in combination with Na₂S₂O₃.Then the behavioral change,convulsion number andmortality rate(within 72 h)were observed,recorded,and compared the differences between the mice groups.RESULT: All of the four sulphydryl compounds had protecting effect on acutely NaCN poisoned mice,among them NAC had most prominent effect (P<0.01).LD₅₀ were raised significantly (P<0.01) in acutely NaCN poisonedmice pretreated with iPNAC.After NaCN poisoned for 1 min,in the grouPof treatment with iPNAC in combination with Na₂S₂O₃,convulsion number and mortality of mice (within 72 hours) were declined significantly(P<0.01).It was not significant different when compared with the grouPwhich were treated by iPNaNO₂ in combination with Na₂S₂O₃.CONCLUSION: Sulphydryl compounds antagonizing cyanide intoxication are related with Sulphydryl.All of the results indicate that NAC has the antidotal effects on acutely NaCN poisoned animals.

Key words: sodium cyanide, sulphydryl compounds, N-acetyl-L-cysteine, poisoning, antidote