Nitisinone and Baricitinib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Baricitinib
Nitisinone
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased baricitinib exposure
Interaction Deep Dive
Coadministration of baricitinib (OAT3 substrate) with probenecid (strong OAT3 inhibitor) resulted in a 2-fold increase in baricitinib AUC during a pharmacokinetic study. If coadministration of baricitinib and a strong OAT3 inhibitor is necessary in patients with rheumatoid arthritis, reduce baricitinib dose to 1 mg once daily2. If coadministration is required in patients with COVID-19, reduce a recommended dose of 4 mg once daily to 2 mg once daily, and reduce a dose of 2 mg once daily to 1 mg once daily. If the recommended dosage is 1 mg once daily, consider discontinuing the OAT3 inhibitor (probenecid) 1.
Why it happens (mechanism)
Inhibition of OAT3-mediated efflux transport of baricitinib
Literature reports
1 report — tap to read
a) During a pharmacokinetic study, coadministration of baricitinib with probenecid (strong OAT3 inhibitor) resulted in an approximately 2-fold increase in baricitinib AUC (0 to infinity) with no effect on Cmax and Tmax 2.
Common questions
Can I take Nitisinone and Baricitinib together?
Increased baricitinib exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nitisinone and Baricitinib interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Nitisinone or Baricitinib need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Eli Lilly and Company: Fact sheet for healthcare providers Emergency Use Authorization (EUA) of baricitinib. US Food & Drug Administration (FDA). Silver Spring, MD. 2021.
- Product Information: OLUMIANT(R) oral tablets, baricitinib oral tablets. Lilly USA LLC (per FDA), Indianapolis, IN, 2020. DailyMed
Keep reading about Baricitinib
Keep reading about Nitisinone
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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