Larotrectinib 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
Larotrectinib
No brand names on recordColchicine
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.
Let's talk about taking larotrectinib (a cancer medicine) together with colchicine (used for gout and some other conditions). Your body normally breaks down colchicine using an enzyme called CYP3A4. Larotrectinib can slow that enzyme down, which means colchicine can build up higher than it should in your body.
When colchicine builds up, it can cause serious problems like bad diarrhea, muscle weakness, and other toxic effects. The good news is your care team can manage this. Please don't stop or change either medicine on your own. Just check in with your pharmacist or doctor so they can adjust things and keep an eye on you.
Effect: Larotrectinib (a CYP3A4 inhibitor) may reduce CYP3A4-mediated metabolism of colchicine, increasing colchicine exposure and risk of dose-dependent toxicity.
- Direction: Increased colchicine effect/toxicity (neither drug is a prodrug here).
- Mechanism: Inhibition of CYP3A4 (colchicine is also a P-gp substrate).
- Evidence: Theoretical; onset unspecified. Severity rated major.
- Management: Avoid concomitant use given potential for serious/life-threatening toxicity. If necessary, reduce colchicine daily dose or frequency and monitor closely for toxicity (GI symptoms, myopathy, myelosuppression). Greater caution in hepatic or renal impairment.
What happens
Increased colchicine exposure and an increased risk of colchicine-related toxicity
Interaction Deep Dive
Because of the risk of serious, potentially fatal toxicity, colchicine should not be taken together with CYP3A4 inhibitors. When combined therapy with colchicine and a CYP3A4 inhibitor cannot be avoided, modify the colchicine dose (either by lowering the total daily amount or by decreasing how often it is given) while closely watching for signs of colchicine toxicity1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
Here is how a care team typically handles this combination:
- Avoid together when possible because of the potential for serious toxicity.
- If both are truly needed, your team may lower the colchicine dose or take it less often and monitor you more closely for side effects.
- Watch for warning signs like ongoing diarrhea, vomiting, muscle pain or weakness, numbness, or unusual tiredness, and report them right away.
What you should do: Keep taking both exactly as prescribed until you speak with your pharmacist or prescriber. Do not adjust doses on your own, but do bring this interaction to their attention so they can tailor your plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Larotrectinib and Colchicine together?
Larotrectinib can raise colchicine levels and the risk of serious colchicine toxicity, so this combination is best avoided; if both are needed, your team will lower the colchicine dose or frequency and watch you closely. Talk to your pharmacist or doctor before making any changes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Larotrectinib 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 Larotrectinib and Colchicine interaction managed?
Here is how a care team typically handles this combination: Avoid together when possible because of the potential for serious toxicity. If both are truly needed, your team may lower the colchicine dose or take it less often and monitor you more closely for side effects. Watch for warning signs like ongoing diarrhea, vomiting, muscle pain or weakness, numbness, or unusual tiredness, and report them… 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 Larotrectinib 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 (1)
- Product Information: MITIGARE(R) oral capsules, colchicine oral capsules. Hikma Specialty USA Inc (per FDA), Columbus, OH, 2024. DailyMed
Keep reading about Larotrectinib
Keep reading about Colchicine
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