Drug interactions
Fluorouracil + Trastuzumab deruxtecan
Severity: Moderate
Fluorouracil and Trastuzumab deruxtecan: 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
Both drugs can cause myelosuppression, and trastuzumab deruxtecan commonly causes neutropenia. Combined use can increase the incidence or severity of neutropenia and infection.
What this interaction means in plain words
Fluorouracil and Trastuzumab deruxtecan 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.
Fluorouracil belongs to Oncology; Trastuzumab deruxtecan belongs to Oncology.
Why it happens
Additive myelosuppression from the cytotoxic topoisomerase I inhibitor payload and fluorouracil.
What to do
Monitor complete blood counts before each cycle and manage neutropenia with dose delay or reduction as per labeling. Counsel the patient to report fever promptly.
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 Fluorouracil
Other interactions of Trastuzumab deruxtecan
Frequently asked questions
Can I take Fluorouracil with Trastuzumab deruxtecan?
MediHelp rates the interaction as moderate. Fluorouracil and Trastuzumab deruxtecan 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. Both drugs can cause myelosuppression, and trastuzumab deruxtecan commonly causes neutropenia. Combined use can increase the incidence or severity of neutropenia and infection.
How serious is the interaction between Fluorouracil and Trastuzumab deruxtecan?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor complete blood counts before each cycle and manage neutropenia with dose delay or reduction as per labeling. Counsel the patient to report fever promptly.
What other medicines interact with Fluorouracil?
MediHelp also lists interactions of Fluorouracil with, for example, Adenovirus types 4 and 7 live, Axicabtagene ciloleucel, Belatacept. The full list is on the Fluorouracil page.
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