Background: In the treatment of children with brain tumors, dexamethasone and methotrexate are often utilized simultaneously. As previously shown, dexamethasone can reduce the efficacy of methotrexate in vitro (Anticancer Res. 14: 1585-8). Consequently, DEX has been avoided during high dose methotrexate infusions in a pilot study.
Methods: Side effects of methotrexate with dexamethasone (N = 33) were retrospectively compared with the side effects of methotrexate without dexamethasone (N = 24).
Results: No serious brain edema in any of the groups was observed; there was no difference in bone marrow toxicity, or mucositis. Liver enzymes, however, were significantly higher when methotrexate was given with dexamethasone: GOT [glutamate oxalacetate transaminase] 76 +/- 73 versus 19 +/- 12, GPT (glutamate pyrovate transaminase) 140 +/- 199 versus 39 +/- 31 IU/I (P < 0.01). This higher hepatotoxicity was not related to differences in methotrexate serum-levels.
Conclusions: Dexamethasone can be eliminated from high dose methotrexate protocols for children.