Drug interactions
Fluoxetine + Hydroxyzine
Severity: Major
Fluoxetine and Hydroxyzine: 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
Both drugs can prolong the QT interval, and combining them may increase the risk of torsades de pointes, particularly with other risk factors. Fluoxetine may also inhibit CYP2D6 modestly and add sedation.
What this interaction means in plain words
Fluoxetine and Hydroxyzine 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; Hydroxyzine belongs to Respiratory.
Why it happens
Additive QT interval prolongation through cardiac potassium channel blockade.
What to do
Avoid the combination in patients with QT risk factors; otherwise obtain an ECG and keep potassium and magnesium normal. Use a non-QT-prolonging alternative for anxiety or pruritus when possible.
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 Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Other interactions of Hydroxyzine
- Droperidol + Hydroxyzine Contraindicated
- Hydroxyzine + Pimozide Contraindicated
- Hydroxyzine + Thioridazine Contraindicated
- Hydroxyzine + Vandetanib Contraindicated
- Alfentanil + Hydroxyzine Major
- Amiodarone + Hydroxyzine Major
Frequently asked questions
Can I take Fluoxetine with Hydroxyzine?
MediHelp rates the interaction as major. Fluoxetine and Hydroxyzine 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. Both drugs can prolong the QT interval, and combining them may increase the risk of torsades de pointes, particularly with other risk factors. Fluoxetine may also inhibit CYP2D6 modestly and add sedation.
How serious is the interaction between Fluoxetine and Hydroxyzine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination in patients with QT risk factors; otherwise obtain an ECG and keep potassium and magnesium normal. Use a non-QT-prolonging alternative for anxiety or pruritus when possible.
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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