Drug interactions
Fostemsavir + Mefloquine
Severity: Moderate
Fostemsavir and Mefloquine: moderate 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
Mefloquine prolongs the QT interval, and fostemsavir has caused QTc prolongation at supratherapeutic doses. Combined use may add to arrhythmia risk, particularly with other risk factors.
What this interaction means in plain words
Fostemsavir and Mefloquine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Fostemsavir belongs to Anti Virals; Mefloquine belongs to Anti Parasitic.
Why it happens
Additive pharmacodynamic QT prolongation.
What to do
Check a baseline ECG and correct electrolytes. Monitor the QTc during coadministration.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Mefloquine
- Arsenic trioxide + Mefloquine Contraindicated
- Dronedarone + Mefloquine Contraindicated
- Ibutilide + Mefloquine Contraindicated
- Levoketoconazole + Mefloquine Contraindicated
- Mefloquine + Nilotinib Contraindicated
- Mefloquine + Pimozide Contraindicated
Other interactions of Fostemsavir
- Apalutamide + Fostemsavir Contraindicated
- Carbamazepine + Fostemsavir Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Fostemsavir + Mitotane Contraindicated
- Fostemsavir + Phenytoin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
Frequently asked questions
Can I take Fostemsavir with Mefloquine?
MediHelp rates the interaction as moderate. Fostemsavir and Mefloquine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Mefloquine prolongs the QT interval, and fostemsavir has caused QTc prolongation at supratherapeutic doses. Combined use may add to arrhythmia risk, particularly with other risk factors.
How serious is the interaction between Fostemsavir and Mefloquine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check a baseline ECG and correct electrolytes. Monitor the QTc during coadministration.
What other medicines interact with Mefloquine?
MediHelp also lists interactions of Mefloquine with, for example, Arsenic trioxide, Dronedarone, Ibutilide. The full list is on the Mefloquine page.
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