Drug interactions
Fluoxetine + Fostemsavir
Severity: Moderate
Fluoxetine and Fostemsavir: 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
Fostemsavir has caused QT prolongation at supratherapeutic doses, and fluoxetine can also prolong the QT interval. Combined use may add to the arrhythmia risk, especially with other risk factors. At recommended fostemsavir doses the risk is lower.
What this interaction means in plain words
Fluoxetine and Fostemsavir 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.
Fluoxetine belongs to Central Nervous System; Fostemsavir belongs to Anti Virals.
Why it happens
Additive prolongation of cardiac repolarisation (QT interval).
What to do
Obtain a baseline ECG and monitor it in patients with other QT risk factors; correct potassium and magnesium abnormalities.
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 Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline 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 Fluoxetine with Fostemsavir?
MediHelp rates the interaction as moderate. Fluoxetine and Fostemsavir 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 has caused QT prolongation at supratherapeutic doses, and fluoxetine can also prolong the QT interval. Combined use may add to the arrhythmia risk, especially with other risk factors. At recommended fostemsavir doses the risk is lower.
How serious is the interaction between Fluoxetine and Fostemsavir?
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 monitor it in patients with other QT risk factors; correct potassium and magnesium abnormalities.
What other medicines interact with Fluoxetine?
MediHelp also lists interactions of Fluoxetine with, for example, Isocarboxazid, Mavacamten, Methylene blue. The full list is on the Fluoxetine page.
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