Methotrexate is an important anti-cancer drug, which is listed in the World Health Organization’s essential drugs. The therapies using high dose methotrexate (HDMTX) have been commonly used at the National Cancer Hospital (K Hospital) in Vietnam. In order to ensure the effectiveness and safety of this important drug, a therapeutic drug monitoring (TDM) protocol for HDMTX has been formulated by the Pharmacy department at K Hospital and was then approved by the Hospital Director in November 2018.
The objective of this study was to examine the level of compliance with this TDM protocol in clinical practice at the hospital. The study was conducted from July 2019 to February 2020. A total of 174 cycles of HDMTX, including the ones of the treatment for non-hodgkin lymphoma (66.7%), osteosarcoma (30.4%), and acute lymphoblastic leukemia (2.9%), were included in the study. The administrations of 137 cycles were 4-hour transfusion and the remaining cycles’ were 24-hour transfusion. The results showed that there was no cycle fully complied with the protocol. When considering steps in the protocol individually, the compliance percentages were 47.1% for pre-transfusion evaluation, 14.9% for the rehydration and urine alkalization procedure, 58.6% for methotrexate quantification, and 19.0% for rescue procedure with leucovorin. The research results indicated that the compliance proportions with the TDM protocol at K Hospital were low. More studies should be conducted to find out the reasons and difficulties in the adherence to the protocol, or the consequences on patients’ outcomes of the non-compliance to protocol practice so that its adherence can be improved.