Clozapine and Fluoxetine Interaction
Drug interaction information between Clozapine and Fluoxetine.
Clozapine and Fluoxetine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Clozapine and Fluoxetine. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Fluoxetine prevents your body from processing clozapine correctly, leading to higher levels of the drug. This increases the risk of experiencing dangerous side effects.
What To Do
Your doctor should monitor your blood levels and watch you closely for side effects. They may need to adjust your clozapine dose.
FDA Label Information
Monoamine Oxidase Inhibitors (MAOIs): ( 2.9 , 2.10 , 4.1 , 5.2 ) Drugs Metabolized by CYP2D6: Fluoxetine is a potent inhibitor of CYP2D6 enzyme pathway ( 7.7 ) Tricyclic Antidepressants (TCAs): Monitor TCA levels during coadministration with fluoxetine or when fluoxetine has been recently discontinued ( 5.2 , 7.7 ) CNS Acting Drugs: Caution should be used when taken in combination with other centrally acting drugs ( 7.2 ) Benzodiazepines: Diazepam – increased t½, alprazolam - further psychomotor performance decrement due to increased levels ( 7.7 ) Antipsychotics: Potential for elevation...
Clozapine Also Interacts With
- Cyclobenzaprine moderate
- Diphenhydramine moderate
- Sertraline minor
- Escitalopram minor
- Bupropion minor
Fluoxetine Also Interacts With
- Aspirin major
- Warfarin major
- Olanzapine major
- Pimozide major
- Thioridazine major
Frequently Asked Questions
Can I take Clozapine and Fluoxetine together?
This is a moderate interaction. Your doctor should monitor your blood levels and watch you closely for side effects. They may need to adjust your clozapine dose.
How serious is the interaction between Clozapine and Fluoxetine?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Clozapine and Fluoxetine interact?
Fluoxetine prevents your body from processing clozapine correctly, leading to higher levels of the drug. This increases the risk of experiencing dangerous side effects.
Understanding the Clozapine and Fluoxetine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Clozapine belongs to the Atypical Antipsychotic class and Fluoxetine belongs to the Selective Serotonin Reuptake Inhibitor (SSRI) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Fluoxetine prevents your body from processing clozapine correctly, leading to higher levels of the drug. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Clozapine has 42 total documented interactions on file in this dataset, and Fluoxetine has 68. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Your doctor should monitor your blood levels and watch you closely for side effects. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Clozapine or Fluoxetine based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.