Efficacy of hydroxocobalamin for the treatment of acute cyanide poisoning in adult beagle dogs

Introduction: The efficacy of hydroxocobalamin for acute cyanide poisoning was compared with that of saline vehicle in dogs.

Methods: Anesthetized adult beagle dogs were administered potassium cyanide (0.4 mg/kg/min, IV) until 3 min after the onset of apnea. Hydroxocobalamin (75 mg/kg [n = 19] or 150 mg/kg [n = 18], IV) or saline vehicle [n = 17] was then infused over 7.5 min while Animals were ventilated with 100% oxygen, which was stopped after 15 min.

Results: In vehicle-treated Animals cyanide produced deterioration that culminated in a moribund state requiring euthanasia within 4 h in 10 of 17 Animals and in neurological deficits necessitating euthanasia within 2-4 d in an additional 4 Animals (mortality rate 82%). Survival through 14 d was observed in 15 of 19 Animals administered hydroxocobalamin 75 mg/kg (mortality rate 21%), and 18 of 18 administered hydroxocobalamin 150 mg/kg (mortality rate 0%).

Conclusion: Hydroxocobalamin reversed cyanide toxicity and reduced mortality in a canine model.