Colchicine and Voxelotor: 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
Voxelotor
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.
Voxelotor (Oxbryta) can slow down the enzyme your body uses to break down colchicine. When that happens, colchicine can build up in your blood to higher levels than intended. That matters because colchicine has a narrow safety window, and too much of it can cause serious, even life-threatening, problems like severe diarrhea, muscle weakness, and effects on the blood and organs.
The good news is your care team can manage this. They may lower your colchicine dose or space it out further, and watch you more closely. Please don't change either medicine on your own. Just talk with your pharmacist or doctor so they can adjust things safely for you.
Mechanism: Voxelotor is a moderate CYP3A4 inhibitor; it reduces CYP3A4-mediated metabolism of colchicine, increasing colchicine exposure. Colchicine is not a prodrug, so inhibition raises active drug levels and toxicity risk.
Effect: Increased colchicine plasma concentrations with risk of fatal toxicity (GI, myelosuppression, neuromyopathy, multiorgan failure). Colchicine is narrow-therapeutic-index.
Evidence: Theoretical; severity major.
Management:
- Avoid combination where possible, including within 14 days.
- If required, reduce colchicine daily dose or frequency per gout-flare, prophylaxis, or FMF regimens.
- Avoid entirely in renal or hepatic impairment.
- Monitor for toxicity; discontinue colchicine immediately if suspected.
What happens
Increased colchicine exposure and an increased risk of fatal toxicity
Interaction Deep Dive
The combination of colchicine with a moderate CYP3A4 inhibitor should be avoided, since it can raise colchicine plasma levels and lead to fatal colchicine toxicity. When coadministration cannot be avoided, modify the colchicine regimen by lowering either the daily amount or how often it is taken3. Where concurrent use, or use within a 14 day window, is necessary, the colchicine dosing for a gout flare should be cut from the standard 1.2 mg (2 tablets) followed one hour later by 0.6 mg (1 tablets) to a single 1.2 mg (2 tablets) dose, and any repeat dose must wait at least 3 days. For gout flare prophylaxis, decrease the colchicine dose from 0.6 mg twice daily to 0.6 mg daily, or from 0.6 mg once daily to 0.3 mg once daily. For patients who have familial Mediterranean fever, when colchicine must be used together with a moderate CYP3A4 inhibitor, the daily colchicine total should not exceed 1.2 mg (which may be administered as 0.6 mg twice daily). Watch for the signs and symptoms of colchicine toxicity and stop colchicine right away if it is suspected 2. In addition, patients with renal or hepatic impairment should not receive colchicine together with moderate CYP3A4 inhibitors 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
Keep taking both medicines exactly as prescribed and let your pharmacist and prescriber know you are on both. This combination is best avoided, but when it is needed your care team can manage it safely.
- Your colchicine dose may be reduced (lower amount or less often), individualized to your situation (gout flare, prevention, or familial Mediterranean fever).
- Your team may monitor you more closely for colchicine toxicity.
- This combination is generally avoided in people with kidney or liver problems.
Call your care team right away if you notice severe diarrhea, vomiting, muscle weakness, numbness, or unusual weakness or fatigue.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
Common questions
Can I take Colchicine and Voxelotor together?
Voxelotor can raise colchicine to dangerous levels, so this combination is best avoided; if both are needed, your care team will lower your colchicine dose and watch you closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Voxelotor 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 Colchicine and Voxelotor interaction managed?
Keep taking both medicines exactly as prescribed and let your pharmacist and prescriber know you are on both. This combination is best avoided, but when it is needed your care team can manage it safely. Your colchicine dose may be reduced (lower amount or less often), individualized to your situation (gout flare, prevention, or familial Mediterranean fever). Your team may monitor you more closely… 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 Colchicine or Voxelotor 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 Voxelotor
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.
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