Methotrexate poisoning with acute hepatorenal dysfunction.

A 17-year-old girl receiving high-dose methotrexate for the treatment of osteosarcoma developed complications of acute renal failure and liver dysfunction with a coagulation disorder. The methotrexate concentrations were quickly reduced from 600 micromol/L to 50 micromol/L by treatment with plasma exchange and hemodialysis at 72 hours after discontinuation of the drug. After this reduction, continuous hemodiafiltration was initiated to further lower the methotrexate concentrations because of the persistently high and then the actual rebound in the plasma concentrations after plasma exchange and hemodialysis treatment. Continuous hemodiafiltration was able to reduce the concentrations without any rebound, despite its low column clearance. The rebound in plasma methotrexate concentrations seems to be corrected by plasma methotrexate after plasma exchange and/or hemodialysis.