Phenelzine and Desvenlafaxine Interaction
Drug interaction information between Phenelzine and Desvenlafaxine.
Phenelzine and Desvenlafaxine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Phenelzine and Desvenlafaxine. 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
These medications both raise serotonin levels in your body. Combining them can lead to a dangerous condition called serotonin syndrome, which affects your heart rate, blood pressure, and muscles.
What To Do
Do not take these drugs together. You must typically wait at least 14 days after stopping one before starting the other to avoid a dangerous interaction.
FDA Label Information
Examples selegiline, tranylcypromine, isocarboxazid, phenelzine, linezolid, methylene blue Other Serotonergic Drugs Clinical Impact Concomitant use of PRISTIQ with other serotonergic drugs increases the risk of serotonin syndrome.
Phenelzine Also Interacts With
- Sertraline moderate
- Fluoxetine moderate
- Citalopram moderate
- Venlafaxine moderate
- Fluvoxamine moderate
Desvenlafaxine Also Interacts With
- Aspirin moderate
- Linezolid moderate
- Tranylcypromine moderate
- Selegiline moderate
- Warfarin moderate
Frequently Asked Questions
Can I take Phenelzine and Desvenlafaxine together?
This is a moderate interaction. Do not take these drugs together. You must typically wait at least 14 days after stopping one before starting the other to avoid a dangerous interaction.
How serious is the interaction between Phenelzine and Desvenlafaxine?
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 Desvenlafaxine interact?
These medications both raise serotonin levels in your body. Combining them can lead to a dangerous condition called serotonin syndrome, which affects your heart rate, blood pressure, and muscles.
Understanding the Phenelzine and Desvenlafaxine 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 Desvenlafaxine belongs to the Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: These medications both raise serotonin levels in your body. 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 Desvenlafaxine has 19. 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 take these drugs together. 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 Desvenlafaxine 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.