Hemoperfusion for methotrexate removal.

Removal of methotrexate by Amberlite XAD-4 hemoperfusion was determined in a patient with metastatic breast carcinoma. During 4 hr of hemoperfusion the plasma concentration of methotrexate fell from 5.5 x 10(-7) M TO 3.1 x 10(-7) M. After hemoperfusion methotrexate concentration increased as a consequence of multicompartmental pharmacokinetics to 5.5 x 10(-7) M and then slowly declined. Plasma methotrexate clearance decreased from 79 ml/min 30 min into hemoperfusion to 28 ml/min at the conclusion. In vitro clearance of methotrexate by 17 artificial kidneys, Amberlite XAD-4, and uncoated charcoal was determined. Uncoated charcoal had the greatest clearance of methotrexate of all the devices tested. We conclude that: (1) Amberlite XAD-4 transiently reduces plasma methotrexate concentration; (2) in vitro, charcoal hemoperfusion is more effective than XAD-4 in removing methotrexate; (3) as a consequence of the multicompartmental pharmacokinetics of methotrexate a postperfusion rebound in plasma methotrexate concentration is to be expected.