High Dose Methotrexate Induced Toxicity in Children with Hematological Malignancy: Incidence and Relation to MTX Level

Background: Methotrexate is an effective drug for the treatment of malignant
hematopoietic neoplasm in children; its antineoplastic activity is enhanced when
MTX is used at high dose. Monitoring of patient after high dose methotrexate
administration is essential to manage toxicity. Aim of the work: Incidence of
HDMTX toxicity in children with hematological malignancies and relation to
MTX level.
Patients & Methods: A prospective study conducted on 142 patients with
hematological malignancies who received 467 cycles of HDMTX scheduled in
their treatment protocols during the period from May 2020 to September 2022,
assessment of the patients before HDMTX administration and after the dose to
detect any toxicities.
Results: GIT toxicity reported in 434 (92.9%) followed by renal toxicity in form
of raised serum creatinine in 114 (24.4%), hepatic toxicity in 51 (10.9%) and
myelosuppression in 48 (10.3%). Toxic MTX level at 23h & 66h significantly
associated with increased creatinine level. In addition, Toxic MTX level at 23h
significantly associated with all systems and GIT toxicities. MTX level at 42h
didn’t show any significant relations
Conclusion: GIT toxicities are the most common HDMTX toxicities and related
to high 23 h MTX level. Both high 23h & 66 h MTX level are good indicators
of renal toxicities.