Drug interactions
Dofetilide + Posaconazole
Severity: Major
Dofetilide 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 drugs prolong the QT interval, and combining them raises the risk of torsades de pointes. Dofetilide has a narrow therapeutic index and relies on QT-guided dosing.
What this interaction means in plain words
Dofetilide 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.
Dofetilide belongs to Cardiovascular; Posaconazole belongs to Anti Fungals.
Why it happens
Additive QT prolongation via hERG potassium channel blockade.
What to do
Avoid the combination where possible and choose a non-QT-prolonging antifungal. If unavoidable, monitor ECG and electrolytes closely, with inpatient monitoring at initiation.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Other interactions of Dofetilide
- Amiodarone + Dofetilide Contraindicated
- Amisulpride + Dofetilide Contraindicated
- Amlodipine-hydrochlorothiazide-valsartan + Dofetilide Contraindicated
- Amlodipine-olmesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Candesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Captopril-hydrochlorothiazide + Dofetilide Contraindicated
Frequently asked questions
Can I take Dofetilide with Posaconazole?
MediHelp rates the interaction as major. Dofetilide 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 drugs prolong the QT interval, and combining them raises the risk of torsades de pointes. Dofetilide has a narrow therapeutic index and relies on QT-guided dosing.
How serious is the interaction between Dofetilide 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 the combination where possible and choose a non-QT-prolonging antifungal. If unavoidable, monitor ECG and electrolytes closely, with inpatient monitoring at initiation.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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