Drug interactions
Fostemsavir + Levofloxacin
Severity: Moderate
Fostemsavir and Levofloxacin: 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
Both drugs can prolong the QT interval. Fostemsavir has been associated with QTc prolongation at supratherapeutic doses, so combining it with levofloxacin may add to the risk of ventricular arrhythmia including torsades de pointes, especially with other risk factors.
What this interaction means in plain words
Fostemsavir and Levofloxacin 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; Levofloxacin belongs to Anti Bacterial.
Why it happens
Additive pharmacodynamic QT prolongation through cardiac repolarization effects (hERG potassium channel blockade).
What to do
Obtain a baseline ECG and correct hypokalemia and hypomagnesemia before combining. Monitor the ECG in patients with other QT risk factors or cardiac disease, and consider an alternative antibiotic if the QTc becomes markedly prolonged.
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 Levofloxacin
- Dronedarone + Levofloxacin Contraindicated
- Ibutilide + Levofloxacin Contraindicated
- Levofloxacin + Thioridazine Contraindicated
- Levofloxacin + Vandetanib Contraindicated
- Levofloxacin + Ziprasidone Contraindicated
- Adagrasib + Levofloxacin Major
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 Levofloxacin?
MediHelp rates the interaction as moderate. Fostemsavir and Levofloxacin 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. Both drugs can prolong the QT interval. Fostemsavir has been associated with QTc prolongation at supratherapeutic doses, so combining it with levofloxacin may add to the risk of ventricular arrhythmia including torsades de pointes, especially with other risk factors.
How serious is the interaction between Fostemsavir and Levofloxacin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and correct hypokalemia and hypomagnesemia before combining. Monitor the ECG in patients with other QT risk factors or cardiac disease, and consider an alternative antibiotic if the QTc becomes markedly prolonged.
What other medicines interact with Levofloxacin?
MediHelp also lists interactions of Levofloxacin with, for example, Dronedarone, Ibutilide, Thioridazine. The full list is on the Levofloxacin page.
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