[Clinical evaluation of severe toxicity in two patients with acute lymphoblastic leukemia receiving outpatient methotrexate therapy].

Methotrexate (MTX) is now widely used for the treatment of acute leukemia and non-Hodgkin lymphoma in the pediatric oncology field and is thought to be one of the key drugs for this treatment. A regimen utilizing high dose MTX (HD-MTX) with leucovorin rescue is being investigated as effective chemotherapy in the patients with these kinds of cancer. Relatively large amounts of MTX (225 mg/m2) are given to such outpatients by intravenous push as a course of maintenance therapy. It is said that those amounts will infuse safely. However, we experienced two serious cases-patients T.H. and M.Y.--which developed into severe side effects after this treatment. Both patients showed acute renal failure, severe myelosuppression, erosion around the oral and anal region, and continuous diarrhea. Judging from the serum concentration of MTX, patient T. H. was exposed to more than the maximum allowance serum MTX level for 9.6 days, patient M. Y. for 6.5 days. This suggests physicians must pay attention to the clinical symptoms even after treatment using MTX without HD-MTX.