DEXAMETHASONE INCREASES HEPATOTOXICITY OF MTX IN CHILDREN WITH BRAIN-TUMORS

Background: In the treatment of children with brain tumors, dexamethas one and methotrexate are often utilized simultaneously As previously s hown, dexamethasone can reduce the efficacy of methotrexate in vitro ( Anticancer Res.14: 1585-8). Consequently DEX has been avoided during h igh dose methotrexate infusions in a pilot study. Methods: Side effect s of methotrexate with dexamethasone (N=33) were retrospectively compa red with the side effects of methotrexate without dexamethasone (N=24) . Results: No serious brain edema in any of the groups was observed; t here was no difference in bone marrow toxicity, or mucositis. Liver en zymes, 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 v ersus 39 +/- 31 IU/I (P < 0.01). This higher hepatotoxicity was not re lated to differences in methotrexate serum-levels. Conclusions: Dexame thasone can be eliminated from high dose methotrexate protocols for ch ildren.