Drug interactions
Cyclophosphamide + Rifampin
Severity: Moderate
Cyclophosphamide and Rifampin: 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
Rifampin induces CYP2B6, CYP2C and CYP3A4 and can increase formation of cyclophosphamide active metabolites, raising the risk of toxicity such as myelosuppression. The effect on antitumor efficacy is uncertain.
What this interaction means in plain words
Cyclophosphamide and Rifampin 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
Induction of CYP2B6, CYP2C and CYP3A4 by rifampin alters cyclophosphamide metabolism and increases activation.
What to do
Monitor blood counts and signs of cyclophosphamide toxicity during co-use. Consider an alternative antimicrobial where appropriate.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Cyclophosphamide and Rifampin, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Cyclophosphamide
Frequently asked questions
Can I take Cyclophosphamide with Rifampin?
MediHelp rates the interaction as moderate. Cyclophosphamide and Rifampin 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. Rifampin induces CYP2B6, CYP2C and CYP3A4 and can increase formation of cyclophosphamide active metabolites, raising the risk of toxicity such as myelosuppression. The effect on antitumor efficacy is uncertain.
How serious is the interaction between Cyclophosphamide and Rifampin?
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 blood counts and signs of cyclophosphamide toxicity during co-use. Consider an alternative antimicrobial where appropriate.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
