Drug interactions
Phenytoin + Upadacitinib
Severity: Major
Phenytoin and Upadacitinib: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phenytoin may reduce upadacitinib exposure and diminish its effectiveness in inflammatory disease. Strong CYP3A4 inducers such as rifampin have lowered upadacitinib exposure.
What this interaction means in plain words
Phenytoin and Upadacitinib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Phenytoin belongs to Central Nervous System; Upadacitinib belongs to Musculoskeletal.
Why it happens
Phenytoin induces CYP3A4, which increases the metabolism of upadacitinib.
What to do
Avoid the combination and consider a non-inducing antiseizure drug. If used together, monitor for loss of disease control.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Phenytoin and Upadacitinib, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Upadacitinib
- Abrocitinib + Upadacitinib Contraindicated
- Adenovirus types 4 and 7 live + Upadacitinib Contraindicated
- Baricitinib + Upadacitinib Contraindicated
- Bcg vaccine live + Upadacitinib Contraindicated
- Cyclosporine + Upadacitinib Contraindicated
- Dengue vaccine + Upadacitinib Contraindicated
Frequently asked questions
Can I take Phenytoin with Upadacitinib?
MediHelp rates the interaction as major. Phenytoin and Upadacitinib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenytoin may reduce upadacitinib exposure and diminish its effectiveness in inflammatory disease. Strong CYP3A4 inducers such as rifampin have lowered upadacitinib exposure.
How serious is the interaction between Phenytoin and Upadacitinib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and consider a non-inducing antiseizure drug. If used together, monitor for loss of disease control.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
