Ritlecitinib and Colchicine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ritlecitinib
Colchicine
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.
Here's the deal in plain terms. Ritlecitinib (Litfulo) can slow down the enzyme in your body (called CYP3A4) that helps break down colchicine. When colchicine isn't cleared as fast, it can build up in your blood. Colchicine is a drug where too much can be very dangerous, even life-threatening, so this matters.
The good news is that this is a well-understood, manageable situation. If you need both, your care team can lower your colchicine dose or space it out and watch you closely. Please don't change anything on your own. Just talk with your pharmacist or doctor about the best plan for you.
Mechanism: Ritlecitinib is a moderate CYP3A4 inhibitor; colchicine is a CYP3A4 (and P-gp) substrate. Inhibition reduces colchicine clearance, raising plasma concentrations and AUC, increasing risk of dose-dependent, potentially fatal colchicine toxicity (GI, myelosuppression, neuromuscular).
Direction: increased colchicine exposure (neither is a prodrug here). Evidence: theoretical. Onset: unspecified.
Management:
- Avoid combination when possible, especially with renal or hepatic impairment.
- If required, reduce colchicine daily dose or frequency (gout flare: 1.2 mg once, repeat no sooner than 3 days; prophylaxis: 0.6 mg BID to 0.6 mg daily, or 0.6 mg daily to 0.3 mg daily; FMF: max 1.2 mg/day).
- Monitor for toxicity; discontinue colchicine if suspected.
What happens
Increased colchicine exposure and an increased risk of fatal toxicity
Interaction Deep Dive
Concurrent administration of colchicine with a moderate CYP3A4 inhibitor should be avoided, because this combination can raise colchicine plasma levels and produce fatal colchicine toxicity. When coadministration cannot be avoided, modify the colchicine dose by lowering either the daily amount or how often it is given3. For gout flare treatment where concomitant use, or use within the prior 14 days, is necessary, the colchicine regimen should be changed from the original 1.2 mg (2 tablets) followed by 0.6 mg (1 tablet) one hour later to a single 1.2 mg (2 tablet) dose, and any repeat dose should not be administered before 3 days have passed. When colchicine is used for gout flare prophylaxis, decrease the dose from an original 0.6 mg twice daily to 0.6 mg daily, or from an original 0.6 mg once daily to 0.3 mg once daily. For patients who have familial Mediterranean fever and require concurrent colchicine and a moderate CYP3A4 inhibitor, the colchicine daily total should not exceed 1.2 mg (which may be provided as 0.6 mg twice daily). Watch for signs and symptoms indicative of colchicine toxicity, and stop colchicine at once if toxicity is suspected 2. In addition, in patients who have renal or hepatic impairment, avoid using colchicine together with moderate CYP3A4 inhibitors 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
What your care team may do:
- Try to avoid using the two together when possible, particularly if you have kidney or liver problems.
- If both are needed, lower your colchicine dose or take it less often. Your team will individualize this based on why you take colchicine (gout flare, gout prevention, or familial Mediterranean fever).
- Watch you more closely for signs of colchicine toxicity.
What you should do: Keep taking both exactly as prescribed until you speak with your team. Tell your pharmacist or doctor you take these together, and report any unusual muscle weakness, severe diarrhea, vomiting, numbness, or signs of infection right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
Common questions
Can I take Ritlecitinib and Colchicine together?
Ritlecitinib can raise colchicine levels and increase the risk of serious toxicity, so your care team may lower your colchicine dose and monitor you closely. Don't change either medication on your own, but do flag this combination to your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ritlecitinib and Colchicine 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 is the Ritlecitinib and Colchicine interaction managed?
What your care team may do: Try to avoid using the two together when possible, particularly if you have kidney or liver problems. If both are needed, lower your colchicine dose or take it less often. Your team will individualize this based on why you take colchicine (gout flare, gout prevention, or familial Mediterranean fever). Watch you more closely for signs of colchicine toxicity. What you sho… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Ritlecitinib or Colchicine 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 (3)
- Product Information: LODOCO(R) oral tablets, colchicine oral tablets. AGEPHA Pharma USA, LLC (per FDA), Parsippany, NJ, 2023. DailyMed
- Product Information: COLCRYS oral tablets, colchicine oral tablets. Takeda Pharmaceuticals America Inc (per FDA), Deerfield, IL, 2020. DailyMed
- Product Information: GLOPERBA(R) oral solution, colchicine oral solution. Romeg Therapeutics LLC (per FDA), Woburn, MA, 2019. DailyMed
Keep reading about Ritlecitinib
Keep reading about Colchicine
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