SAFETY AND EFFICACY OF 4-METHYLPYRAZOLE FOR TREATMENT OF SUSPECTED ORCONFIRMED ETHYLENE-GLYCOL INTOXICATION IN DOGS - 107 CASES (1983-1995)

Objective-To evaluate safety and efficacy of 4-methylpyrazole (4-MP) t reatment in dogs and to determine clinical signs and outcome of, and c linicopathologic abnormalities in, dogs treated in early or late stage s of ethylene glycol (EG) intoxication. Design-Retrospective study. An imals-107 dogs. Procedure-For dogs treated with 4-MP, 1 of 2 dosage re gimens was usually used: 20 mg/kg of body weight, IV, initially, 15 mg /kg 17 hours later, and 5 mg/kg 25 and 36 hours after the initial dose , or 20 mg/kg, IV, initially, 15 mg/kg 12 and 24 hours later, and 5 mg /kg 36 hours after the initial dose. Results-Neither adverse clinical signs nor clinicopathologic abnormalities were associated with the adm inistration of 4-MP except in 1 dog, which developed tachypnea, gaggin g, excess salivation, and trembling after the second dose of 4-MP was given. Ethylene glycol intoxication was confirmed in 37 dogs. Of these , 21 were azotemic or became azotemic within 18 hours after admission, and only 1 of the 21 survived. All 16 dogs that did not become azotem ic survived, Median time from EG ingestion to treatment with 4-MP was 5 hours (range, 2 to 8.5 hours) for dogs that were not azotemic at adm ission and 14.5 hours (range, 8.5 to 38 hours) for dogs that were azot emic at admission. Clinical Implications-4-MP was a safe and effective treatment for EG intoxication when it was given before sufficient qua ntities of EG had been metabolized to induce renal failure. Dogs treat ed within 8 hours of EG ingestion had a good prognosis.