Using a Bedside Algorithm to Individually Dose High-dose Methotrexate for Patients at Risk for Toxicity.

We developed a bedside algorithm for individually adjusting the high-dose methotrexate (HDMTX) dose (5 g/m) given to patients with acute lymphoblastic leukemia at high risk for methotrexate toxicity. Data were reviewed for 8 patients receiving 21 cycles of HDMTX as per our algorithm. Eleven cycles began with 5 g/m, 10 cycles began with a preinfusion 20% to 25% dose reduction. Neither mean MTX AUC (2320.5±179.1 vs. 2080.4±161.7 µmol×h/L), mean Cpss (64.3±7.9 vs. 60.8±6.1 µM), nor toxicities were statistically different between groups. Our algorithm allowed the safe administration of HDMTX to patients at risk of MTX toxicities and obviated the need for preinfusion dose reduction.