Removal of methotrexate by peritoneal dialysis and hemodialysis in a single patient with end-stage renal disease

Background: Although methotrexate is highly bound to albumin, it is thought to be removed by hemodialysis and not by peritoneal dialysis. We are not aware of any direct comparison in the same patient. Case Report/ Methods: A 60-year-old patient on continuous ambulatory peritoneal dialysis was admitted to the East Alabama Medical Center for stomatitis and pancytopenia after being given 10 mg of methotrexate for his rheumatoid arthritis. Measurements of total methotrexate levels were made before, during, and after sequential peritoneal and hemodialysis treatments. Results: We found that the clearance of methotrexate measured in the dialysate was equal in the first hour of dialysis for both types of dialysis, although serum levels were markedly lower in hemodialysis compared to peritoneal dialysis. Conclusion: Methotrexate was cleared by peritoneal dialysis in the first hour of an exchange and was not associated with a rebound in serum levels. Hemodialysis was associated with lower serum levels; however, there was also a significant rebound 2 hours after the procedure ended. Since neither procedure was able to preclude the death of the patient, other more effective means of methotrexate elimination should be employed.