Phenytoin and Methylphenidate Interaction
Drug interaction information between Phenytoin and Methylphenidate.
Phenytoin and Methylphenidate have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Phenytoin and Methylphenidate. 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
Methylphenidate can slow down how your liver processes phenytoin, which may cause the phenytoin to build up in your body.
Phenytoin Also Interacts With
- Nirmatrelvir/Ritonavir major
- Posaconazole major
- Ranolazine major
- Voriconazole major
- Apixaban moderate
Methylphenidate Also Interacts With
- Safinamide major
- Dexmethylphenidate moderate
- Risperidone moderate
- Linezolid minor
- Phenelzine minor
Frequently Asked Questions
What SPL severity band is on file for Phenytoin + Methylphenidate?
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 Methylphenidate's 11. In the minor band specifically: Phenytoin has 120 (also Atorvastatin, Omeprazole, Simvastatin, Paroxetine); Methylphenidate has 8 (also Linezolid, Phenelzine, Tranylcypromine, Selegiline).
What mechanism field is on file for Phenytoin and Methylphenidate?
Methylphenidate can slow down how your liver processes phenytoin, which may cause the phenytoin to build up in your body.
Phenytoin carries more major-labeled pairs than Methylphenidate
SPL source-record counts only. This page's band is minor · classes on file: Phenytoin (Anticonvulsant (Hydantoin)); Methylphenidate (CNS Stimulant).
Phenytoin has 4 major-labeled pairs vs Methylphenidate's 1. 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
- Paroxetine
1 major · 2 moderate · 8 minor · 11 total
- Other minor peers for Methylphenidate
- Linezolid
- Phenelzine
- Tranylcypromine
- Selegiline
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.