| Effects of Methemoglobin Versus Potassium Cyanide Intoxication. (2002) | |||||||||
Abstract | |||||||||
| Studies were conducted to evaluate the effects of pre-existing methemoglobinemia induced by WR 6026 and hydroxylamine hydrochloride on the ability of the dog to resist lethal cyanide (KCN) intoxication. The following items were accomplished or concluded during the course of the study period: A protective index against lethal KCN intoxication of 1.75 was established for a 5-6% blood methemoglobin level induced by oral administration of WR 6026 prior to KCN administration. Blood methemoglobin levels of approximately 10% were induced with a single administration of WR 6026 at a level (14.5 mg/kg) which produced no signs of drug-related toxicity. The interval between administration of WR 6026 and feeding (up to 4 hours) did not have an effect on blood methemoglobin levels. Intramuscular injection of a 5 or 17.5% solution of hydroxylamine hydrochloride resulted in blood methemoglobin levels of 10-12% within 5-10 minutes after injection. Intravaneous injection of sodium thiosulfate (Na2S2O3) following lethal KCN intoxication resulted in alleviation of toxic symptoms and an increase in the expected survival rate, in contrast to a study conducted with cyanide followed by intramuscular injection of Na2S2O3, in which no alleviation of toxic symptoms occurred. Hydroxylamine hydrochloride had a prophylactic, but not therapeutic, effect against lethal KCN intoxication when administered intramuscularly at a level of 10 mg/kg. A protective index against lethal KCN intoxication of 3.77 was established for 10-12% methemoglobinemia induced by prophylactic intramuscular injection of hydroxylamine hydrochloride. | |||||||||
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