A single center retrospective analysis of a protocol for high-dose methotrexate and leucovorin rescue administration

Methotrexate has a wide dosing range. High-dose methotrexate is a dose of 1000 mg/m² or greater. In the 1970s, the incidence of mortality associated with High-dose methotrexate ranged from 4.6 to 6%. In 2012, the University of Maryland Medical Center implemented a standardized high-dose methotrexate protocol. The purpose of this study was to evaluate whether the institution followed recommendations based on the Bleyer nomogram for the administration of high-dose methotrexate more closely after the implementation of the protocol.

In this retrospective chart review, 37 patients received 119 cycles of high-dose methotrexate before the protocol implementation (1 January 2009 through 31 December 2010) and 45 patients received 106 cycles of high-dose methotrexate after protocol implementation (1 January 2013 through 31 December 2014). Patient characteristics, protocol data, and complications were analyzed.

Protocol implementation significantly reduced the deviation of methotrexate level timing at 24, 48, and 72 h: median 7.47 vs. 1.46 h, 7.23 vs. 1.35 h, and 7.00 vs. 1.52 h before and after implementation, respectively (p < 0.0001 for each). The protocol significantly reduced deviation of the first dose of leucovorin administration: median 5.2 vs. 0.675 h before and after implementation, respectively (p<0.0001). After protocol implementation, there was an increase in the use of leucovorin prescriptions written appropriately for patients discharged before methotrexate levels reached a value of ≤0.05 µmol/L.

Implementation of a protocol for the administration of high-dose methotrexate improved the adherence to consensus recommendations. Further analysis is needed to assess clinical pharmacist involvement and the cost savings implications within this protocol.