Venlafaxine and Phenelzine Interaction
Drug interaction information between Venlafaxine and Phenelzine.
Venlafaxine and Phenelzine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Venlafaxine and Phenelzine. 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
Both medications increase serotonin levels, and using them together can cause a severe reaction. This happens because the body cannot process the excess serotonin safely.
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.
Venlafaxine Also Interacts With
- Aspirin moderate
- Metoprolol minor
- Fluoxetine minor
- Alprazolam minor
- Warfarin minor
Phenelzine Also Interacts With
- Sertraline moderate
- Fluoxetine moderate
- Citalopram moderate
- Fluvoxamine moderate
- Desvenlafaxine moderate
Frequently Asked Questions
What SPL severity band is on file for Venlafaxine + Phenelzine?
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?
Phenelzine has 27 labeled pairs on file vs Venlafaxine's 22. In the moderate band specifically: Venlafaxine has 2 (also Aspirin); Phenelzine has 11 (also Sertraline, Fluoxetine, Citalopram, Fluvoxamine).
What mechanism field is on file for Venlafaxine and Phenelzine?
Both medications increase serotonin levels, and using them together can cause a severe reaction. This happens because the body cannot process the excess serotonin safely.
Phenelzine's labeled portfolio outnumbers Venlafaxine
SPL source-record counts only. This page's band is moderate · classes on file: Venlafaxine (Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)); Phenelzine (Monoamine Oxidase Inhibitor (MAOI)).
0 major · 11 moderate · 16 minor · 27 total
- Other moderate peers for Phenelzine
- Sertraline
- Fluoxetine
- Citalopram
- Fluvoxamine
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.