Drug interactions
Moxifloxacin + Posaconazole
Severity: Major
Moxifloxacin 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 can prolong the QT interval, and using them together raises the chance of torsades de pointes. The risk is greater with electrolyte disturbances, bradycardia, structural heart disease or other QT-prolonging drugs.
What this interaction means in plain words
Moxifloxacin 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.
Moxifloxacin belongs to Anti Bacterial; Posaconazole belongs to Anti Fungals.
Why it happens
Additive blockade of cardiac IKr (hERG) potassium channels leading to delayed ventricular repolarization.
What to do
Avoid the combination where an alternative antibacterial or antifungal exists. If it is necessary, obtain a baseline and follow-up ECG and correct potassium and magnesium before and during therapy.
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 Moxifloxacin
- Amiodarone + Moxifloxacin Contraindicated
- Arsenic trioxide + Moxifloxacin Contraindicated
- Disopyramide + Moxifloxacin Contraindicated
- Dofetilide + Moxifloxacin Contraindicated
- Dronedarone + Moxifloxacin Contraindicated
- Droperidol + Moxifloxacin 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 Moxifloxacin with Posaconazole?
MediHelp rates the interaction as major. Moxifloxacin 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 can prolong the QT interval, and using them together raises the chance of torsades de pointes. The risk is greater with electrolyte disturbances, bradycardia, structural heart disease or other QT-prolonging drugs.
How serious is the interaction between Moxifloxacin 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 an alternative antibacterial or antifungal exists. If it is necessary, obtain a baseline and follow-up ECG and correct potassium and magnesium before and during therapy.
What other medicines interact with Moxifloxacin?
MediHelp also lists interactions of Moxifloxacin with, for example, Amiodarone, Arsenic trioxide, Disopyramide. The full list is on the Moxifloxacin page.
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