Abstract

This study investigated the efficacy of hydroxocobalamin in reducing cyanide toxicity arising from amygdalin administration in rats. Amygdalin at its therapeutic dose (20 mg/kg body weight) was co-administered with hydroxocobalamin to rats at two different levels (25 mg/kg and 50 mg/kg body weight) for 14 days. Symptoms of cyanide toxicity in the blood and liver were monitored in the animals and compared with the control. One of the rats who received amygdalin without the antidote died of cyanide poisoning before the end of the experimental period while no mortality was recorded in rats who received the antidote. There was significant reduction (P < 0.05) in blood cyanide and serum lactate concentration in a dose-dependent manner in rats who received the antidote compared with the control. Blood of rats fed amygdalin showed significant elevation in packed cell volume (PCV) and haemoglobin concentration accompanied with significant reduction in blood pH while these abnormalities were reversed by hydroxocobalamin. Histological studies of the liver of amygdalin-fed rats revealed marked alteration in cellular architecture which was not noticeable in rats who received the antidote. We conclude that rats can be protected from the deleterious effects of cyanide poisoning due to amygdalin ingestion by the concomitant administration of hydroxocobalamin.

Key words: Amygdalin, antidote, hydroxocobalamin, cyanide toxicity.