Phenytoin and Paroxetine Interaction
Drug interaction information between Phenytoin and Paroxetine.
Phenytoin and Paroxetine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Phenytoin and Paroxetine. 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
Phenytoin causes your body to break down paroxetine faster than usual, which can lower the amount of medicine in your system.
FDA Label Information
Warfarin Increased and decreased PT/INR responses have been reported when phenytoin is coadministered with warfarin Other Corticosteroids, doxycycline, estrogens, furosemide, oral contraceptives, paroxetine, quinidine, rifampin, sertraline, theophylline, and vitamin D Drugs whose level is decreased by phenytoin Antiepileptic drugs a Carbamazepine, felbamate, lamotrigine, topiramate, oxcarbazepine Antilipidemic agents Atorvastatin, fluvastatin, simvastatin Antiviral agents Efavirenz, lopinavir/ritonavir, indinavir, nelfinavir, ritonavir, saquinavir Fosamprenavir: phenytoin when given with...
Phenytoin Also Interacts With
- Nirmatrelvir/Ritonavir major
- Posaconazole major
- Ranolazine major
- Voriconazole major
- Apixaban moderate
Paroxetine Also Interacts With
- Linezolid major
- Pimozide major
- Thioridazine major
- Phenelzine moderate
- Tranylcypromine moderate
Frequently Asked Questions
What SPL severity band is on file for Phenytoin + Paroxetine?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Phenytoin has 147 labeled pairs on file vs Paroxetine's 51. In the minor band specifically: Phenytoin has 120 (also Atorvastatin, Omeprazole, Simvastatin, Methylphenidate); Paroxetine has 44 (also Buspirone, Clopidogrel, Aspirin, Venlafaxine).
What mechanism field is on file for Phenytoin and Paroxetine?
Phenytoin causes your body to break down paroxetine faster than usual, which can lower the amount of medicine in your system.
Phenytoin carries more major-labeled pairs than Paroxetine
SPL source-record counts only. This page's band is minor · classes on file: Phenytoin (Anticonvulsant (Hydantoin)); Paroxetine (Selective Serotonin Reuptake Inhibitor (SSRI)).
Phenytoin has 4 major-labeled pairs vs Paroxetine's 3. This page itself is in the minor band, not the major band.
4 major · 23 moderate · 120 minor · 147 total
- Other minor peers for Phenytoin
- Atorvastatin
- Omeprazole
- Simvastatin
- Methylphenidate
3 major · 4 moderate · 44 minor · 51 total
- Other minor peers for Paroxetine
- Buspirone
- Clopidogrel
- Aspirin
- Venlafaxine
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.