Fluvoxamine and Phenelzine Interaction
Drug interaction information between Fluvoxamine and Phenelzine.
Fluvoxamine and Phenelzine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Fluvoxamine and Phenelzine. 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
Both drugs increase the amount of serotonin in your brain, which can cause a very dangerous and life-threatening reaction.
What To Do
Do not use these medicines together because the combination can be fatal.
FDA Label Information
Drug Interactions In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) there have been reports of serious, sometimes fatal, reactions.
Fluvoxamine Also Interacts With
- Tizanidine major
- Lithium moderate
- Tasimelteon moderate
- Metoprolol minor
- Omeprazole minor
Phenelzine Also Interacts With
- Sertraline moderate
- Fluoxetine moderate
- Citalopram moderate
- Venlafaxine moderate
- Desvenlafaxine moderate
Frequently Asked Questions
Can I take Fluvoxamine and Phenelzine together?
This is a moderate interaction. Do not use these medicines together because the combination can be fatal.
How serious is the interaction between Fluvoxamine and Phenelzine?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Fluvoxamine and Phenelzine interact?
Both drugs increase the amount of serotonin in your brain, which can cause a very dangerous and life-threatening reaction.
Understanding the Fluvoxamine and Phenelzine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Fluvoxamine belongs to the Selective Serotonin Reuptake Inhibitor (SSRI) class and Phenelzine belongs to the Monoamine Oxidase Inhibitor (MAOI) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Both drugs increase the amount of serotonin in your brain, which can cause a very dangerous and life-threatening reaction. 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. Fluvoxamine has 40 total documented interactions on file in this dataset, and Phenelzine has 27. 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: Do not use these medicines together because the combination can be fatal. 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 Fluvoxamine or Phenelzine 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.