4-Methylpyrazole as treatment for naturally acquired ethylene glycol intoxication in dogs.

Eight dogs with ethylene glycol intoxication were treated with 4-methylpyrazole, an alcohol dehydrogenase inhibitor. Dogs had clinical signs referable to ethylene glycol ingestion including ataxia, depression, vomiting, polyuria, and dehydration. Metabolic abnormalities included high anion gap metabolic acidosis, serum hyperosmolality, isosthenuria, and monohydrate and dihydrate calcium oxalate crystalluria. Serum and urine ethylene glycol concentrations were determined to confirm ingestion of ethylene glycol. A 50-mg/ml solution of 4-methylpyrazole in propylene glycol was administered iv as follows: initial treatment, 20 mg/kg of body weight; at 17 hours after admission, 15 mg/kg; at 25 hours after admission, 5 mg/kg. By 24 hours after admission, all dogs had clinical and metabolic improvement. Of the 8 dogs, 7 were released within 3 days of admission. Four of the 8 dogs returned for follow-up evaluation, at which time biochemical or hematologic abnormalities were not observed.