Diazepam and Fluoxetine Interaction
Drug interaction information between Diazepam and Fluoxetine.
Diazepam and Fluoxetine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Diazepam 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 makes diazepam stay in your body for a longer time than usual. This can lead to a buildup of the drug and cause more side effects.
What To Do
Watch for increased drowsiness and be careful when driving or using machinery. Your doctor might need to adjust your treatment plan.
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...
Diazepam Also Interacts With
- Clonazepam moderate
- Mirtazapine moderate
- Raloxifene moderate
- Omeprazole minor
- Ketoconazole minor
Fluoxetine Also Interacts With
- Aspirin major
- Warfarin major
- Olanzapine major
- Pimozide major
- Thioridazine major
Frequently Asked Questions
Can I take Diazepam and Fluoxetine together?
This is a moderate interaction. Watch for increased drowsiness and be careful when driving or using machinery. Your doctor might need to adjust your treatment plan.
How serious is the interaction between Diazepam 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 Diazepam and Fluoxetine interact?
Fluoxetine makes diazepam stay in your body for a longer time than usual. This can lead to a buildup of the drug and cause more side effects.
Understanding the Diazepam and Fluoxetine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Diazepam belongs to the Benzodiazepine 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 makes diazepam stay in your body for a longer time than usual. 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. Diazepam has 26 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: Watch for increased drowsiness and be careful when driving or using machinery. 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 Diazepam 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.