Drug interactions
Cyclophosphamide + Influenza a vaccine
Severity: Moderate
Cyclophosphamide and Influenza a vaccine: 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
Cyclophosphamide-induced immunosuppression can reduce the antibody response to the H5N1 influenza vaccine, so protection may be incomplete. The vaccine is inactivated, so the concern is reduced efficacy rather than vaccine-related infection.
What this interaction means in plain words
Cyclophosphamide and Influenza a vaccine 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.
Why it happens
Cytotoxic suppression of lymphocyte function reduces vaccine immunogenicity.
What to do
Vaccinate before starting cyclophosphamide when possible, ideally at least two weeks before, or time doses at the nadir-recovery phase of the cycle. Consider assessing response or additional doses if the patient remains at high risk.
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
Frequently asked questions
Can I take Cyclophosphamide with Influenza a vaccine?
MediHelp rates the interaction as moderate. Cyclophosphamide and Influenza a vaccine 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-induced immunosuppression can reduce the antibody response to the H5N1 influenza vaccine, so protection may be incomplete. The vaccine is inactivated, so the concern is reduced efficacy rather than vaccine-related infection.
How serious is the interaction between Cyclophosphamide and Influenza a vaccine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Vaccinate before starting cyclophosphamide when possible, ideally at least two weeks before, or time doses at the nadir-recovery phase of the cycle. Consider assessing response or additional doses if the patient remains at high risk.
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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