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.