Momelotinib and Gemfibrozil: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Gemfibrozil
Momelotinib
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 momelotinib exposure and an increased risk of momelotinib-related adverse reactions
Interaction Deep Dive
Coadministration of momelotinib (an OATP1B1 and OATP1B3 substrate) with gemfibrozil (an OATP1B1 and OATP1B3 inhibitor) may increase momelotinib Cmax and AUC, which may increase the risk of adverse reactions with momelotinib. Monitor patients concomitantly receiving an OATP1B1/OATP1B3 inhibitor for adverse reactions and consider momelotinib dose modifications1.
Why it happens (mechanism)
Inhibition of OATP1B1-mediated metabolism of momelotinib; inhibition of OATP1B3-mediated metabolism of momelotinib
Literature reports
1 report — tap to read
a) In clinical studies, momelotinib Cmax increased by 40% and AUC increased by 57% following concomitant use of momelotinib with a single dose of a rifAMPin (OATP1B1 inhibitor). The M21 metabolite Cmax increased by 6% and AUC increased by 12% 1.
Common questions
Can I take Momelotinib and Gemfibrozil together?
Increased momelotinib exposure and an increased risk of momelotinib-related adverse reactions Always confirm with your pharmacist or prescriber before making any change.
How serious is the Momelotinib and Gemfibrozil 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 Momelotinib or Gemfibrozil 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 (1)
- Product Information: OJJAARA oral tablets, momelotinib oral route. GlaxoSmithKline (per FDA), Durham, NC, 2023. DailyMed
Keep reading about Gemfibrozil
Keep reading about Momelotinib
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist