Extracorporeal management of severe methotrexate toxicity and acute kidney injury in the absence of glucarpidase.

Methotrexate (MTX) is widely used in oncology but carries a risk of severe nephrotoxicity, especially at high doses. We report a case of a man in his 70s with diffuse large B-cell lymphoma who developed acute kidney injury (AKI) and refractory hypotension 48 hours after receiving high-dose methotrexate (HD-MTX). Despite standard interventions including leucovorin rescue and urine alkalinisation, MTX clearance was impaired due to AKI. In the absence of glucarpidase, the patient was successfully managed with intermittent high-flux haemodialysis followed by continuous renal replacement therapy. This approach facilitated gradual MTX clearance, resolution of hypotension and recovery of renal function. This case highlights the critical need for early recognition of MTX toxicity and the potential role of individualised extracorporeal therapies when glucarpidase is unavailable.