Drug interactions
Lefamulin + Posaconazole
Severity: Major
Lefamulin 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
Lefamulin is a CYP3A4 and P-gp substrate and also prolongs the QT interval. Posaconazole raises lefamulin exposure and adds its own QT effect, increasing the risk of arrhythmia with oral lefamulin.
What this interaction means in plain words
Lefamulin 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.
Lefamulin belongs to Anti Bacterial; Posaconazole belongs to Anti Fungals.
Why it happens
Strong CYP3A4 and P-gp inhibition increases lefamulin exposure, with additive QTc prolongation.
What to do
Avoid oral lefamulin with posaconazole and choose another antibiotic. If the intravenous form is used, monitor ECG and electrolytes.
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 Lefamulin
- Lefamulin + Methadone Contraindicated
- Lefamulin + Pimavanserin Contraindicated
- Lefamulin + Pimozide Contraindicated
- Lefamulin + Quinidine Contraindicated
- Alfuzosin + Lefamulin Major
- Amiodarone + Lefamulin Major
Frequently asked questions
Can I take Lefamulin with Posaconazole?
MediHelp rates the interaction as major. Lefamulin 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. Lefamulin is a CYP3A4 and P-gp substrate and also prolongs the QT interval. Posaconazole raises lefamulin exposure and adds its own QT effect, increasing the risk of arrhythmia with oral lefamulin.
How serious is the interaction between Lefamulin 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 oral lefamulin with posaconazole and choose another antibiotic. If the intravenous form is used, monitor ECG and electrolytes.
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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