Drug interactions
Fluconazole + Itraconazole
Severity: Major
Fluconazole and Itraconazole: major 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
Both azoles can prolong the QT interval, and fluconazole may increase itraconazole exposure. Combined use adds to the risk of arrhythmia and has little rationale as dual azole therapy.
What this interaction means in plain words
Fluconazole and Itraconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fluconazole belongs to Anti Fungals; Itraconazole belongs to Anti Fungals.
Why it happens
Additive QT prolongation, with possible CYP3A4 inhibition raising itraconazole levels.
What to do
Avoid concurrent use of two systemic azoles unless clearly needed. If required, monitor ECG and electrolytes and consider itraconazole levels.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Fluconazole
- Dihydroergotamine intranasal + Fluconazole Contraindicated
- Dihydroergotamine + Fluconazole Contraindicated
- Dofetilide + Fluconazole Contraindicated
- Domperidone + Fluconazole Contraindicated
- Dronedarone + Fluconazole Contraindicated
- Erythromycin + Fluconazole Contraindicated
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 Fluconazole with Itraconazole?
MediHelp rates the interaction as major. Fluconazole and Itraconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both azoles can prolong the QT interval, and fluconazole may increase itraconazole exposure. Combined use adds to the risk of arrhythmia and has little rationale as dual azole therapy.
How serious is the interaction between Fluconazole and Itraconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use of two systemic azoles unless clearly needed. If required, monitor ECG and electrolytes and consider itraconazole levels.
What other medicines interact with Fluconazole?
MediHelp also lists interactions of Fluconazole with, for example, Dihydroergotamine intranasal, Dihydroergotamine, Dofetilide. The full list is on the Fluconazole page.
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