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(2)) 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(2), 10 cycles began with a preinfusion 20% to 25% dose reduction. Neither mean MTX AUC (2320.5 +/- 179.1 vs. 2080.4 +/- 161.7 mu mol x h/L), mean Cpss (64.3 +/- 7.9 vs. 60.8 +/- 6.1 mu M), 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.