Protection against Cyanide Poisoning by the Co-administration of Sodium Nitrite and Hydroxylamine in Rats

Abstract

1 The protectiveness of combined treatment with sodium nitrite (SN) and hydroxylamine (HA) in cyanide intoxication was investigated in male rats. 2 Pretreatment with equimolar dose of SN or HA produced a significant protection against cyanide poisoning as shown by the protection index (LD50 of cyanide in protected rats/LD50 of cyanide in saline-treated rats). 3 The co-administration of SN and HA as a split dose produced an optimal and sustained methaemoglobinaemia. 4 Pretreatment with combined SN and HA administration at different time intervals offered sustained protection against cyanide and resultant cytochrome oxidase inhibition. 5 Adjunction of sodium thiosulphate (STS) in the SN + HA regimen further augmented the protection against cyanide poisoning. 6 The results suggest that pretreatment with SN + HA co-administration could significantly reduce the toxic manifestation of cyanide.