Drug interactions
Fluoxetine + Metoprolol
Severity: Major
Fluoxetine and Metoprolol: major interaction.
Last updated Sources: US FDA label
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 strongly inhibits CYP2D6, the main enzyme clearing metoprolol, so metoprolol exposure can rise several-fold. This can cause bradycardia, hypotension and fatigue, and loss of beta1 selectivity.
What this interaction means in plain words
Fluoxetine and Metoprolol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fluoxetine belongs to Central Nervous System; Metoprolol belongs to Cardiovascular.
Why it happens
Inhibition of CYP2D6-mediated metoprolol metabolism by fluoxetine and its metabolite norfluoxetine.
What to do
Monitor heart rate and blood pressure and reduce the metoprolol dose as needed, or use a beta-blocker not dependent on CYP2D6 such as bisoprolol or atenolol. The inhibition persists for weeks after fluoxetine is stopped.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Metoprolol
- Metoprolol + Thioridazine Contraindicated
- Amifostine + Metoprolol Major
- Amiodarone + Metoprolol Major
- Atenolol-chlorthalidone + Metoprolol Major
- Atenolol + Metoprolol Major
- Betaxolol + Metoprolol Major
Other interactions of Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Fluoxetine with Metoprolol?
MediHelp rates the interaction as major. Fluoxetine and Metoprolol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Fluoxetine strongly inhibits CYP2D6, the main enzyme clearing metoprolol, so metoprolol exposure can rise several-fold. This can cause bradycardia, hypotension and fatigue, and loss of beta1 selectivity.
How serious is the interaction between Fluoxetine and Metoprolol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor heart rate and blood pressure and reduce the metoprolol dose as needed, or use a beta-blocker not dependent on CYP2D6 such as bisoprolol or atenolol. The inhibition persists for weeks after fluoxetine is stopped.
What other medicines interact with Metoprolol?
MediHelp also lists interactions of Metoprolol with, for example, Thioridazine, Amifostine, Amiodarone. The full list is on the Metoprolol page.
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