A case of delayed methotrexate clearance following administration of a complementary medication containing chlorophyll.

ABSTRACT

A 54-year-old male with relapsed primary cerebral lymphoma and normal renal function was treated with methotrexate (MTX) 3 g/m(2) monthly by intravenous infusion. Throughout treatment the patient self-administered a complementary medicine (Jason Winter's chlorophyll®), which he was advised to cease during methotrexate treatment due to the potential for unknown interactions. For the first four cycles, chlorophyll was ceased two days prior to commencement of methotrexate and withheld until clearance. These cycles were administered without complication, and the methotrexate level reduced to <0.05 µmol/L within three days of each dose. Prior to cycle 5, chlorophyll was not ceased and there were no changes to concomitant medications. A literature search found no documented interactions between methotrexate and chlorophyll and the chemotherapy was administered without a delay in treatment. The methotrexate level three days post-administration was 0.36 µmol/L and did not reduce to <0.05 µmol/L until day 10. Consequently, from cycles 6 to 12, the methotrexate dose was halved, and the patient ceased chlorophyll 48 h prior to methotrexate administration until clearance. There were no further episodes of delayed methotrexate clearance. No impurities were detected in a sample of Jason Winter's chlorophyll®. It is therefore likely that the patient's delayed methotrexate clearance was due to an interaction with chlorophyll. It is recommended that such chlorophyll containing preparations be avoided in patients treated with methotrexate.