Drug interactions
Fluconazole + Posaconazole
Severity: Major
Fluconazole and Posaconazole: 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 azole antifungals can prolong the QT interval, so combining them raises the risk of torsades de pointes. Dual azole therapy also offers little added benefit in most situations and increases hepatotoxicity risk.
What this interaction means in plain words
Fluconazole and Posaconazole 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; Posaconazole belongs to Anti Fungals.
Why it happens
Additive QT prolongation through cardiac potassium channel blockade.
What to do
Avoid combining two azoles unless clearly justified. If used together, monitor ECG, electrolytes and liver tests closely.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Frequently asked questions
Can I take Fluconazole with Posaconazole?
MediHelp rates the interaction as major. Fluconazole and Posaconazole 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 azole antifungals can prolong the QT interval, so combining them raises the risk of torsades de pointes. Dual azole therapy also offers little added benefit in most situations and increases hepatotoxicity risk.
How serious is the interaction between Fluconazole and Posaconazole?
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 combining two azoles unless clearly justified. If used together, monitor ECG, electrolytes and liver tests closely.
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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