Inhalation toxicology of acute exposure to aliphatic nitriles.

Male CD-1 mice were exposed for 60 min to toxic concentrations of acetonitrile, propionitrile, or n-butyronitrile and were maintained for the following 14 d. The LC50 values for acetonitrile, propionitrile, and n-butyronitrile were 2,693, 163, and 249 ppm, respectively. Pretreatment with Na2S2O3 or NaNO2, two common inorganic cyanide antagonists, can provide significant (p < 0.05) protection against the mortality associated with exposure to lethal concentrations of these nitriles. Administration of Na2S2O3 consistently provided a greater measure of protection than did NaNO2 against nitrile poisoning. Pretreatment with a heptatotoxic dose of CCl4 can protect mice against death from inhalation of lethal concentrations of these nitriles. The present results are compared with those of previous studies, and the conclusions support the rationale for administration of inorganic cyanide antagonists to individuals poisoned by inhalation of acetonitrile, propionitrile, or n-butyronitrile.