Cyclophosphamide and Fluconazole: Drug Interaction Guide

Quick answer: This combination requires caution. Cyclophosphamide and Fluconazole can be used together with adjustments and monitoring.

Interaction severity: Moderate — caution required

How Cyclophosphamide interacts with Fluconazole

Fluconazole inhibits CYP2C9 and CYP3A4, reducing conversion of cyclophosphamide to its active alkylating metabolite (4-hydroxycyclophosphamide), potentially reducing efficacy and altering toxicity profile.

What you should do

Prefer alternative antifungal prophylaxis (e.g., posaconazole timing-separated) in patients receiving cyclophosphamide-based regimens; consult oncology pharmacist.

Key facts

Severity

Moderate — caution required

Mechanism

Fluconazole inhibits CYP2C9 and CYP3A4, reducing conversion of cyclophosphamide to its active alkylating metabolite (4-h...

Action

Prefer alternative antifungal prophylaxis (e.g., posaconazole timing-separated) in patients receiving cyclophosphamide-b...

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Cyclophosphamide and Fluconazole together?

With caution. Prefer alternative antifungal prophylaxis (e.g., posaconazole timing-separated) in patients receiving cyclophosphamide-based regimens; consult oncology pharmacist.

What is the severity of this interaction?

The interaction between Cyclophosphamide and Fluconazole is classified as Moderate — caution required. Fluconazole inhibits CYP2C9 and CYP3A4, reducing conversion of cyclophosphamide to its active alkylating metabolite (4-hydroxycyclophosphamide), potentially reducing efficacy and altering toxicity profile.

What should I do if I'm prescribed both?

Prefer alternative antifungal prophylaxis (e.g., posaconazole timing-separated) in patients receiving cyclophosphamide-based regimens; consult oncology pharmacist. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.