Nitrite/thiosulfate treated acute cyanide poisoning: estimated kinetics after antidote

A 34 year old, 73 kg man ingested a 1 gram potassium cyanide pellet in a suicide attempt. Within one hour, coma, apnea, metabolic acidosis, and seizures developed. Sodium nitrite and sodium thiosulfate were administered. Dramatic improvement in the clinical condition occurred by the completion of antidote infusion. Methemoglobin level was 2% immediately after nitrite administration. Serial whole blood cyanide levels were obtained, documenting a highest measured level of 15.68 mcg/mL. Estimations of toxicokinetic parameters including terminal half-life (t 1/2) (19 hours), clearance (163 mL/minute), and volume of distribution (Vd) (0.41 L/kg) were calculated. The nitrite/thiosulfate combination was clinically efficacious in this case and resulted in complete recovery.