Drug interactions
Fluoxetine + Lofexidine
Severity: Moderate
Fluoxetine 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
Fluoxetine is a strong CYP2D6 inhibitor and can raise lofexidine exposure, increasing hypotension, orthostasis and bradycardia. Both drugs can also prolong the QT interval, adding to arrhythmia risk.
What this interaction means in plain words
Fluoxetine 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.
Fluoxetine belongs to Central Nervous System; Lofexidine belongs to Central Nervous System.
Why it happens
Inhibition of CYP2D6-mediated lofexidine metabolism plus additive QT prolongation.
What to do
Monitor blood pressure, heart rate and ECG, and consider reducing the lofexidine dose. Correct electrolyte abnormalities and avoid further QT-prolonging drugs.
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 Lofexidine
- Adagrasib + Lofexidine Major
- Alfuzosin + Lofexidine Major
- Amiodarone + Lofexidine Major
- Amisulpride + Lofexidine Major
- Anagrelide + Lofexidine Major
- Apomorphine + Lofexidine Major
Frequently asked questions
Can I take Fluoxetine with Lofexidine?
MediHelp rates the interaction as moderate. Fluoxetine 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. Fluoxetine is a strong CYP2D6 inhibitor and can raise lofexidine exposure, increasing hypotension, orthostasis and bradycardia. Both drugs can also prolong the QT interval, adding to arrhythmia risk.
How serious is the interaction between Fluoxetine 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: Monitor blood pressure, heart rate and ECG, and consider reducing the lofexidine dose. Correct electrolyte abnormalities and avoid further QT-prolonging drugs.
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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