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Phenelzine and Fluvoxamine Interaction

Drug interaction information between Phenelzine and Fluvoxamine.

Phenelzine and Fluvoxamine have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Phenelzine and Fluvoxamine. 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.

Drug A

Phenelzine

Monoamine Oxidase Inhibitor (MAOI)

Drug B

Fluvoxamine

Selective Serotonin Reuptake Inhibitor (SSRI)

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.

Phenelzine Also Interacts With

View all Phenelzine interactions →

Frequently Asked Questions

Can I take Phenelzine and Fluvoxamine together?

This is a moderate interaction. Do not use these medicines together because the combination can be fatal.

How serious is the interaction between Phenelzine and Fluvoxamine?

This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.

Why do Phenelzine and Fluvoxamine interact?

Both drugs increase the amount of serotonin in your brain, which can cause a very dangerous and life-threatening reaction.

Understanding the Phenelzine and Fluvoxamine Interaction

FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Phenelzine belongs to the Monoamine Oxidase Inhibitor (MAOI) class and Fluvoxamine belongs to the Selective Serotonin Reuptake Inhibitor (SSRI) 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. Phenelzine has 27 total documented interactions on file in this dataset, and Fluvoxamine has 40. 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 Phenelzine or Fluvoxamine 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.