Phenelzine and Fluoxetine Interaction
Drug interaction information between Phenelzine and Fluoxetine.
Phenelzine and Fluoxetine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Phenelzine and Fluoxetine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
These drugs both raise serotonin levels in the brain. Combining them can lead to a dangerous and potentially fatal reaction.
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
- Sertraline moderate
- Citalopram moderate
- Venlafaxine moderate
- Fluvoxamine moderate
- Desvenlafaxine moderate
Fluoxetine Also Interacts With
- Aspirin major
- Warfarin major
- Olanzapine major
- Pimozide major
- Thioridazine major
Frequently Asked Questions
What SPL severity band is on file for Phenelzine + Fluoxetine?
Compiled FDA labeling labels this pair moderate. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Fluoxetine has 68 labeled pairs on file vs Phenelzine's 27. In the moderate band specifically: Phenelzine has 11 (also Sertraline, Citalopram, Venlafaxine, Fluvoxamine); Fluoxetine has 19 (also Alprazolam, Diazepam, Carbamazepine, Haloperidol).
What mechanism field is on file for Phenelzine and Fluoxetine?
These drugs both raise serotonin levels in the brain. Combining them can lead to a dangerous and potentially fatal reaction.
Fluoxetine carries more major-labeled pairs than Phenelzine
SPL source-record counts only. This page's band is moderate · classes on file: Phenelzine (Monoamine Oxidase Inhibitor (MAOI)); Fluoxetine (Selective Serotonin Reuptake Inhibitor (SSRI)).
Fluoxetine has 6 major-labeled pairs vs Phenelzine's 0. This page itself is in the moderate band, not the major band.
0 major · 11 moderate · 16 minor · 27 total
- Other moderate peers for Phenelzine
- Sertraline
- Citalopram
- Venlafaxine
- Fluvoxamine
6 major · 19 moderate · 43 minor · 68 total
- Other moderate peers for Fluoxetine
- Alprazolam
- Diazepam
- Carbamazepine
- Haloperidol
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.