Mechanism of xylitol toxicity in the rabbit

Xylitol toxicity was evaluated by intravenous infusion of varying doses of xylitol at different concentrations into rabbits. Acute toxicity was observed with the administration of 50% xylitol solutions. Striking increases of SGOT and serum LDH levels, along with an increase of urine volume were observed. The LD₅₀ of a 50% solution infused at a rate of 87 mg/kg/min was estimated to be between 4–6 g xylitol/kg body wt. The toxicity correlated well with the concentration of the xylitol solution used or the infusion rate. Both determined serum xylitol concentration and serum osmolality. At a constant infusion rate, the total dose became the important factor in toxicity. The effects of xylitol were compared with those seen after the administration of isosmolar urea, mannitol, or glucose. The acute toxicity of xylitol appears to be mainly due to a hyperosmolar effect. A 5% xylitol solution, essentially isotonic, is nontoxic to the animal in a dose up to 1 g/kg body wt/12 hr even for multiple infusions.