Drug interactions
Fostemsavir + Lithium
Severity: Minor
Fostemsavir and Lithium: minor 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
Lithium can prolong the QT interval and fostemsavir has caused QT prolongation at supratherapeutic doses. At recommended doses the additive effect is likely small, but risk is greater in patients with other QT risk factors.
What this interaction means in plain words
Fostemsavir and Lithium have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fostemsavir belongs to Anti Virals; Lithium belongs to Central Nervous System.
Why it happens
Potential additive effects on cardiac repolarization.
What to do
Use recommended fostemsavir doses and correct potassium and magnesium abnormalities. Obtain an ECG in patients with congenital long QT, heart disease or other QT-prolonging drugs.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium 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 Lithium?
MediHelp rates the interaction as minor. Fostemsavir and Lithium have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Lithium can prolong the QT interval and fostemsavir has caused QT prolongation at supratherapeutic doses. At recommended doses the additive effect is likely small, but risk is greater in patients with other QT risk factors.
How serious is the interaction between Fostemsavir and Lithium?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use recommended fostemsavir doses and correct potassium and magnesium abnormalities. Obtain an ECG in patients with congenital long QT, heart disease or other QT-prolonging drugs.
What other medicines interact with Lithium?
MediHelp also lists interactions of Lithium with, for example, Thioridazine, Vandetanib, Aceclofenac. The full list is on the Lithium page.
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