Drug interactions
Cyclophosphamide + Itraconazole
Severity: Moderate
Cyclophosphamide and Itraconazole: 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
Itraconazole is a strong CYP3A4 inhibitor and can reduce conversion of cyclophosphamide to its active 4-hydroxy metabolite while increasing formation of the neurotoxic and nephrotoxic chloroacetaldehyde. This may alter antitumor efficacy and raise toxicity risk. The legacy direction (cyclophosphamide raising itraconazole) is not the clinically relevant one.
What this interaction means in plain words
Cyclophosphamide and Itraconazole 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; Itraconazole belongs to Anti Fungals.
Why it happens
Itraconazole inhibits CYP3A4 (and CYP2B6-related activation pathways), shifting cyclophosphamide metabolism away from activation toward toxic metabolite formation.
What to do
Where possible choose an antifungal with less CYP3A4 inhibition, or separate azole use from cyclophosphamide dosing. Monitor for neurotoxicity, renal toxicity and reduced response.
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 Itraconazole
- Alfuzosin + Itraconazole Contraindicated
- Alprazolam + Itraconazole Contraindicated
- Avanafil + Itraconazole Contraindicated
- Conivaptan + Itraconazole Contraindicated
- Dihydroergotamine intranasal + Itraconazole Contraindicated
- Dihydroergotamine + Itraconazole Contraindicated
Frequently asked questions
Can I take Cyclophosphamide with Itraconazole?
MediHelp rates the interaction as moderate. Cyclophosphamide and Itraconazole 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. Itraconazole is a strong CYP3A4 inhibitor and can reduce conversion of cyclophosphamide to its active 4-hydroxy metabolite while increasing formation of the neurotoxic and nephrotoxic chloroacetaldehyde. This may alter antitumor efficacy and raise toxicity risk. The legacy direction (cyclophosphamide raising itraconazole) is not the clinically relevant one.
How serious is the interaction between Cyclophosphamide and Itraconazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Where possible choose an antifungal with less CYP3A4 inhibition, or separate azole use from cyclophosphamide dosing. Monitor for neurotoxicity, renal toxicity and reduced response.
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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