Drug interactions
Cyclophosphamide + Trastuzumab
Severity: Moderate
Cyclophosphamide and Trastuzumab: 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
Trastuzumab given with myelosuppressive chemotherapy such as cyclophosphamide is associated with higher rates of neutropenia and febrile neutropenia. Trastuzumab also carries cardiotoxicity risk, which matters when combined with other cardiotoxic regimens.
What this interaction means in plain words
Cyclophosphamide and Trastuzumab 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.
Cyclophosphamide belongs to Oncology; Trastuzumab belongs to Oncology.
Why it happens
Additive myelosuppression with chemotherapy, with trastuzumab adding cardiotoxic risk.
What to do
Monitor neutrophil counts and use G-CSF support per protocol, and assess cardiac function (LVEF) before and during treatment.
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 Cyclophosphamide
Other interactions of Trastuzumab
Frequently asked questions
Can I take Cyclophosphamide with Trastuzumab?
MediHelp rates the interaction as moderate. Cyclophosphamide and Trastuzumab 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. Trastuzumab given with myelosuppressive chemotherapy such as cyclophosphamide is associated with higher rates of neutropenia and febrile neutropenia. Trastuzumab also carries cardiotoxicity risk, which matters when combined with other cardiotoxic regimens.
How serious is the interaction between Cyclophosphamide and Trastuzumab?
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 neutrophil counts and use G-CSF support per protocol, and assess cardiac function (LVEF) before and during treatment.
What other medicines interact with Cyclophosphamide?
MediHelp also lists interactions of Cyclophosphamide with, for example, Adenovirus types 4 and 7 live, Belatacept, Bendamustine. The full list is on the Cyclophosphamide page.
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