Drug interactions
Fostemsavir + Lofexidine
Severity: Moderate
Fostemsavir and Lofexidine: 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
QT prolongation has been seen with fostemsavir at supratherapeutic exposures, and lofexidine also prolongs QT and slows heart rate. Combined use could add to arrhythmia risk, mainly when fostemsavir exposure is raised.
What this interaction means in plain words
Fostemsavir and Lofexidine 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; Lofexidine belongs to Central Nervous System.
Why it happens
Additive QT interval prolongation.
What to do
Obtain a baseline ECG and monitor QTc, particularly if other QT-prolonging drugs or CYP3A inhibitors are present. 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 Lofexidine
- Adagrasib + Lofexidine Major
- Alfuzosin + Lofexidine Major
- Amiodarone + Lofexidine Major
- Amisulpride + Lofexidine Major
- Anagrelide + Lofexidine Major
- Apomorphine + Lofexidine 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 Lofexidine?
MediHelp rates the interaction as moderate. Fostemsavir and Lofexidine 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. QT prolongation has been seen with fostemsavir at supratherapeutic exposures, and lofexidine also prolongs QT and slows heart rate. Combined use could add to arrhythmia risk, mainly when fostemsavir exposure is raised.
How serious is the interaction between Fostemsavir and Lofexidine?
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 QTc, particularly if other QT-prolonging drugs or CYP3A inhibitors are present. Correct potassium and magnesium abnormalities.
What other medicines interact with Lofexidine?
MediHelp also lists interactions of Lofexidine with, for example, Adagrasib, Alfuzosin, Amiodarone. The full list is on the Lofexidine page.
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