Colchicine and Quinidine: 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
Quinidine
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.
Quinidine can make colchicine build up in your body. Your gut and kidneys use a kind of pump (called P-gp) to move colchicine out. Quinidine slows that pump down, so more colchicine stays inside you. Too much colchicine can cause serious problems like bad diarrhea, muscle weakness, and, in severe cases, life-threatening harm.
Because of this risk, using these two together is generally not recommended, and it is especially risky if your kidneys or liver aren't working well. Please don't change anything on your own. Talk with your pharmacist or doctor, who can pick a safer option or carefully adjust and monitor your dose.
Effect: Quinidine (P-gp inhibitor) reduces P-gp-mediated efflux of colchicine, increasing colchicine exposure and risk of toxicity. Neither drug is a prodrug; this is a straightforward increase in colchicine levels.
- Mechanism: inhibition of P-gp transport (colchicine is a P-gp and CYP3A4 substrate).
- Severity/Evidence: contraindicated per labeling; mechanistically theoretical, extrapolated from documented fatal toxicity with other P-gp/CYP3A4 inhibitors.
- Management: Coadministration is contraindicated, and absolutely so in renal or hepatic impairment. If unavoidable in patients with normal renal/hepatic function, reduce colchicine daily dose or dosing frequency and monitor closely for toxicity (GI symptoms, myopathy, neuropathy, cytopenias).
What happens
Increased colchicine exposure and an increased risk of colchicine toxicity
Interaction Deep Dive
Both CYP3A4 and P-gp metabolize colchicine as a substrate. Reports of toxicity have emerged when colchicine was given together with clarithromycin, an agent that inhibits both CYP3A4 and P-gp. Similar toxic effects have been documented when colchicine was combined with a CYP3A4 inhibitor and when it was combined with a P-gp inhibitor3. Because life-threatening and fatal colchicine toxicity has been observed in patients receiving therapeutic doses of colchicine alongside P-gp inhibitors, the joint use of these agents is contraindicated 1. This combination is likewise contraindicated for patients who have renal or hepatic impairment, given that life-threatening and fatal drug interactions have been reported. For patients whose renal and hepatic function is normal 2, should colchicine need to be given with a P-gp inhibitor, modify the colchicine dose by lowering either the daily amount or how often it is taken. Watch carefully for signs of colchicine toxicity 3.
Why it happens (mechanism)
Inhibition of P-gp-mediated colchicine efflux transport
How to manage this interaction
Keep taking both only as your prescriber has told you, and do not stop or change doses on your own.
- This combination is generally considered off-limits because dangerous colchicine buildup has occurred, and it is especially unsafe if you have kidney or liver problems.
- Your care team may choose a different medication instead of one of these.
- If both are truly needed and your kidneys and liver work normally, your team can lower the colchicine dose or space it out further and monitor you more closely.
- Call your pharmacist or doctor right away if you notice severe diarrhea, vomiting, muscle weakness or pain, numbness, or unusual fatigue.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Colchicine and Quinidine together?
Quinidine can raise colchicine to toxic levels by blocking its P-gp export pump, so this pairing is generally avoided; talk to your pharmacist or doctor about a safer alternative or careful dose adjustment and monitoring. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Quinidine 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 Quinidine interaction managed?
Keep taking both only as your prescriber has told you, and do not stop or change doses on your own. This combination is generally considered off-limits because dangerous colchicine buildup has occurred, and it is especially unsafe if you have kidney or liver problems. Your care team may choose a different medication instead of one of these. If both are truly needed and your kidneys and liver work… 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 Quinidine 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 Quinidine
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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