Drug interactions
Glucarpidase + Methotrexate
Severity: Moderate
Glucarpidase and Methotrexate: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Glucarpidase rapidly breaks methotrexate down into DAMPA, which cross-reacts in immunoassays and falsely elevates measured methotrexate. This can lead to misjudged rescue dosing for roughly two days.
What this interaction means in plain words
Glucarpidase and Methotrexate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Glucarpidase belongs to Miscellaneous; Methotrexate belongs to Oncology.
Why it happens
Enzymatic cleavage of methotrexate to DAMPA and glutamate lowers true levels while DAMPA interferes with immunoassays.
What to do
Measure methotrexate with a chromatographic method (e.g., HPLC) for at least 48 hours after glucarpidase. If only immunoassay is available, interpret results with caution.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Glucarpidase
- Glucarpidase + Leucovorin Major
- Folic acid + Glucarpidase Moderate
- Glucarpidase + Pemetrexed Minor
- Glucarpidase + Pralatrexate Minor
Other interactions of Methotrexate
- Acitretin + Methotrexate Contraindicated
- Adenovirus types 4 and 7 live + Methotrexate Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Methotrexate Contraindicated
- Ketorolac + Methotrexate Contraindicated
- Measles mumps and rubella vaccine live + Methotrexate Contraindicated
- Measles mumps and rubella vaccine + Methotrexate Contraindicated
Frequently asked questions
Can I take Glucarpidase with Methotrexate?
MediHelp rates the interaction as moderate. Glucarpidase and Methotrexate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Glucarpidase rapidly breaks methotrexate down into DAMPA, which cross-reacts in immunoassays and falsely elevates measured methotrexate. This can lead to misjudged rescue dosing for roughly two days.
How serious is the interaction between Glucarpidase and Methotrexate?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Measure methotrexate with a chromatographic method (e.g., HPLC) for at least 48 hours after glucarpidase. If only immunoassay is available, interpret results with caution.
What other medicines interact with Glucarpidase?
MediHelp also lists interactions of Glucarpidase with, for example, Leucovorin, Folic acid, Pemetrexed. The full list is on the Glucarpidase page.
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