Avacopan 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
Avacopan
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 what's going on. Avacopan (Tavneos) slows down a liver enzyme called CYP3A4. Colchicine is cleared from your body by that same enzyme. So when you take them together, colchicine can build up higher than usual, which raises the chance of side effects like nausea, diarrhea, stomach cramps, or muscle aches.
Colchicine has a narrow safety window, meaning even a small increase in the level in your blood can matter. The good news is this is very manageable. Your care team may lower your colchicine dose and watch you a bit more closely. Please don't change anything on your own, just check in with your pharmacist or doctor so they can tailor it for you.
Mechanism: Avacopan is a CYP3A4 inhibitor; colchicine is a CYP3A4 (and P-gp) substrate with a narrow therapeutic index. Inhibition reduces colchicine metabolism, increasing its systemic exposure (AUC/Cmax) and risk of toxicity.
Direction: Increased colchicine effect/toxicity (neither drug is a prodrug here).
- Severity: Major; evidence probable; onset unspecified.
- Toxicity watch: GI symptoms (nausea, vomiting, diarrhea), myopathy/rhabdomyolysis, myelosuppression, neuropathy.
- Management: Consider colchicine dose reduction and monitor closely for adverse reactions. Use caution particularly in hepatic or renal impairment. Individualize dosing per care team.
What happens
Increased exposure to CYP3A4 substrate
Interaction Deep Dive
When avacopan, which inhibits CYP3A4, is taken together with a CYP3A4 substrate that has a narrow therapeutic index, the toxicity of that substrate may be heightened; monitor closely for adverse reactions and weigh reducing the dose of the CYP3A4 substrate1.
Why it happens (mechanism)
Inhibition of CYP3A4 substrate metabolism by avacopan
How to manage this interaction
What your care team may do:
- Consider reducing your colchicine dose while you are also taking avacopan.
- Monitor you more closely for signs of colchicine toxicity.
- Adjust and individualize the dose based on your kidney and liver function.
What you can do:
- Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Report new or worsening nausea, vomiting, diarrhea, muscle pain or weakness, tingling, or unusual weakness/fatigue.
- Ask your pharmacist or doctor before starting either drug so they can plan the right dose and follow-up.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) When simvastatin (a CYP3A4 substrate) was given together with avacopan at 60 mg daily for 7 days following food, the AUC and Cmax of simvastatin rose by 3.53-fold and 3.20-fold respectively 1.
b) When midazolam (a CYP3A4 substrate) was given together with avacopan at 30 mg daily for 11 days on an empty stomach, the AUC and Cmax of simvastatin rose by 1.55-fold and 1.81-fold respectively 1.
Common questions
Can I take Avacopan and Colchicine together?
Avacopan can raise colchicine levels and its risk of toxicity, so your care team may lower the colchicine dose and monitor you more closely. Keep taking both as prescribed and report any stomach or muscle symptoms. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Avacopan 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 Avacopan and Colchicine interaction managed?
What your care team may do: Consider reducing your colchicine dose while you are also taking avacopan. Monitor you more closely for signs of colchicine toxicity. Adjust and individualize the dose based on your kidney and liver function. What you can do: Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Report new or worsening nausea, vomiting, diarrhea, m… 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 Avacopan 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: TAVNEOS(R) oral capsules, avacopan oral capsules. ChemoCentryx Inc (per FDA), Thousand Oaks, CA, 2024. DailyMed
Keep reading about Avacopan
Keep reading about Colchicine
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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