A twenty two year-old male with osteogenic sarcoma of the left temporomandibular joint, was received high dose methotrexate (MTX) therapy (200mg/kg-315mg/kg) after the recurrence of tumor. To clarify the safety administration technique for high dose MTX therapy, serum and urine concentration of MTX were measured by means of enzyme assay method.
The results obtained were as follows:
1) The peak serum concentration of MTX reached more than 1.0×10-4 M and two phases of serum disappearance were seen after the infusion.
2) The serum concentration at 24, 48, 72 hours after the infusion were within the safety range, respectively.
3) For several hours after the infusion, the urine concentration of MTX showed high level. On the contrary, the urine pH showed low level with concomitant decrease of its volume.
4) The urine excretion of MTX almost finished within 18 hours after the infusion.
5) The clinical side effect was limited to nausea and vomitting.
From these results, it was suggested that the monitoring of the serum concentration, urine pH and urine volume was important for the safety administration of high doses MTX therapy.
