The large dose administration of the carcinostatic agent methotrexate (MTX), a folic acid antagonist, is effective in treating osteosarcoma but its use is often accompanied by critical adverse effects. Forty-eight hours after administering MTX to a 9-year old female osteosarcoma patient the blood concentration of MTX was 283μM, approximately 280 times higher than the reference level, due to delayed excretion. However, the full amount of calcium folinate (Leucovorin® : LV) needed to antagonize such a high concentration of MTX in the blood was not available since it is produced in very small amounts. Therefore, we recommended blood purification methods such as hemodialysis plus hemoperfusion (HD+HP) and plasma exchange (PE) to reduce the high MTX concentration. HD+HP and PE achieved decreases in the MTX level of 76% and 34%, respectively. Though clinical tests implied hypofunction of the kidney and liver and myelosuppression, serious adverse effects such as decrease in urine volume, jaundice, and infection were not observed.
Thus, the blood purification methods of HD+HP and PE were effective in emergency treatment for a patient with delayed excretion of MTX.
