Therapeutic efficacy of sodium nitrite and 4-dimethylaminophenol or hydroxylamine co-administration against cyanide poisoning in rats

Abstract

1 The therapeutic efficacy of combined treatment of sodium nitrite (NaNO2) and 4-dimethylaminophenol (DMAP) or hydroxylamine (H2NOH) was investigated in potassium cyanide (KCN) intoxication in male rats. 2 Therapy with NaNO 2 (0.27 mmol kg-1) + DMAP (0.09 mmol kg-1) or NaNO2 + H2NOH (0.09 mmol kg-1, produced a protection index (ratio of LD50 of KCN in rats receiving therapy to an LD50 of KCN in rats given only 0.9% saline) of 2.5 and 2.0 respectively. 3 Both the regimens exhibited a beneficial effect in terms of improving the survival time and postural defects in rats exposed to 2 LD50 KCN. 4 NaNO2 + DMAP showed a significant protective effect in the disposition of the plasma cyanide level at different time intervals. 5 The NaNO2 + DMAP regimen was superior to NaNO2 + H2NOH in terms of reactivating the inhibited brain cytochrome oxidase enzyme. 6 The addition of sodium thiosulphate (Na2S2O3) in both the regimens increased the degree of protection. 7 The results suggest that combined therapy with NaNO2 + DMAP could significantly reduce the toxic effects of cyanide, compared with NaNO2+H2NOH treatment.