Use of calcium folinate in the management of accidental methotrexate ingestion in two dogs.

Case Description: 2 English Pointers were suspected of having consumed toxic doses of methotrexate, a dihydrofolate reductase inhibitor frequently used in human and veterinary chemotherapeutic protocols.

Clinical Findings: Potentially toxic plasma concentrations of methotrexate were detected in both dogs. Results of physical examination, a CBC, blood gas analysis, and serum biochemical analysis were predominantly unremarkable, although 1 dog had mild hyponatremia (1372 mmol/L; reference range, 140 to 153 mmol/L) and mild hypocalcemia (1.