Colchicine and Tucatinib: 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
Tucatinib
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.
Tucatinib (Tukysa) is a cancer medicine that strongly blocks a liver enzyme called CYP3A4. Your body uses that same enzyme to break down colchicine (used for gout or familial Mediterranean fever). When tucatinib slows that clean-up process, colchicine can build up to dangerous, even life-threatening, levels. That is a serious problem, so these two are generally not taken together at normal colchicine doses.
Please don't stop either drug on your own. Instead, talk with your oncologist or pharmacist right away. Your care team can manage this by lowering your colchicine dose, choosing a different option, or watching you closely for signs of toxicity.
Mechanism: Tucatinib is a strong CYP3A4 inhibitor; colchicine is a CYP3A4 (and P-gp) substrate. Inhibition reduces colchicine clearance, increasing exposure and the risk of life-threatening, potentially fatal toxicity (neuromyotoxicity, myelosuppression, multiorgan failure).
- Direction: increased colchicine exposure (increases drug effect/toxicity)
- Severity: contraindicated; Evidence: probable
- Renal/hepatic impairment: combination contraindicated, no safe dose
- Normal renal/hepatic function: mandatory colchicine dose reduction (e.g., gout flare 0.6 mg then 0.3 mg 1 h later, repeat no sooner than 3 days; prophylaxis 0.6 mg BID to 0.3 mg daily; FMF max 0.6 mg/day)
- Monitor closely for colchicine toxicity.
What happens
Increased colchicine exposure and an increased risk of fatal toxicity
Interaction Deep Dive
Because life-threatening and fatal colchicine toxicity has occurred in patients taking therapeutic doses of colchicine together with strong CYP3A4 inhibitors, the combined use of these agents is contraindicated1. In patients who have renal or hepatic impairment, coadministration of colchicine with strong CYP3A4 inhibitors (this includes every protease inhibitor apart from fosamprenavir) is likewise contraindicated. When renal and hepatic function are normal, patients who are currently receiving a strong CYP3A4 inhibitor, or who received one during the previous 14 days, require an adjustment to their colchicine dose. To treat a gout flare, lower the colchicine dose to a single 0.6 mg tablet, followed 1 hour later by 0.3 mg, and do not repeat this dose sooner than 3 days. For gout flare prophylaxis, decrease colchicine from an original regimen of 0.6 mg twice daily to 0.3 mg once daily, or from an original regimen of 0.6 mg once daily to 0.3 mg once every other day. In familial Mediterranean fever, the colchicine dose should not exceed a maximum of 0.6 mg per day (which may be administered as 0.3 mg twice daily)2. When colchicine must be given alongside CYP3A4 inhibitors that also inhibit P-gp4, modify the colchicine dose by lowering either the daily amount or the dosing frequency. Watch closely for signs of colchicine toxicity3.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
Keep taking both only as your prescriber directs, and do not change doses yourself. Because tucatinib strongly raises colchicine levels, your care team will handle this deliberately.
- If you have kidney or liver impairment, this combination is not used together.
- If your kidney and liver function are normal, your colchicine dose will be lowered and individualized based on why you take it (gout flare, gout prevention, or familial Mediterranean fever).
- Your team may monitor you more closely for colchicine toxicity, such as muscle weakness, numbness, severe diarrhea, or unusual fatigue.
Report any of these symptoms to your pharmacist or doctor promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) While the interaction between colchicine and boceprevir has not been examined, an interaction involving colchicine and clarithromycin, a potent CYP3A4 inhibitor, led to fatal colchicine toxicity. When a single 0.6 mg dose of colchicine was given to patients (n=23) who had been receiving clarithromycin 250 mg twice daily for 7 days, colchicine Cmax and AUC rose by 227.2% and 281.5%, respectively 21.
b) In a pharmacokinetic study, giving a single dose of colchicine to patients who had received ritonavir 100 mg twice daily for 5 days (n=18) produced increases of 184.4% and 296% in colchicine Cmax and AUC, respectively, relative to baseline values 51.
Common questions
Can I take Colchicine and Tucatinib together?
Tucatinib strongly blocks the enzyme that clears colchicine, so combining them can cause dangerous colchicine buildup; this pairing is contraindicated in kidney or liver impairment and requires a doctor-directed colchicine dose reduction and close monitoring otherwise. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Tucatinib interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Colchicine and Tucatinib interaction managed?
Keep taking both only as your prescriber directs, and do not change doses yourself. Because tucatinib strongly raises colchicine levels, your care team will handle this deliberately. If you have kidney or liver impairment, this combination is not used together. If your kidney and liver function are normal, your colchicine dose will be lowered and individualized based on why you take it (gout flare… Management is individual — always follow your own care team's guidance.
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 Colchicine or Tucatinib 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 (5)
- 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
- Product Information: MITIGARE(R) oral capsules, colchicine oral capsules. Hikma Specialty USA Inc (per FDA), Columbus, OH, 2024. DailyMed
- Product Information: COLCRYS(TM) oral tablets, colchicine oral tablets. AR Scientific, Inc. Philadelphia, PA, 2009. DailyMed
Keep reading about Tucatinib
Keep reading about Colchicine
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