Colchicine and Cimetidine: 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
Cimetidine
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.
Cimetidine (Tagamet) can cause colchicine to build up in your body. Cimetidine slows down the systems that normally break down colchicine and push it out of your cells. When that clearing slows, colchicine levels rise, and too much colchicine can be very dangerous, causing serious and even life-threatening harm.
The good news is that your care team can manage this. Sometimes they lower the colchicine dose, space out the doses, or choose a different option. This is especially important if your kidneys or liver aren't working well. Please don't stop or change either medicine on your own talk with your pharmacist or doctor first so they can guide you safely.
Direction: Cimetidine inhibits both P-gp-mediated efflux and CYP3A4-mediated metabolism of colchicine, decreasing colchicine clearance and increasing systemic exposure (AUC/Cmax). Colchicine is active drug (not a prodrug), so raised exposure means greater toxicity risk, including fatal toxicity.
- Severity: Contraindicated; evidence probable.
- Onset: Unspecified.
- Management: If coadministration is unavoidable, reduce colchicine daily dose by 50-75% or reduce dosing frequency. Combination is contraindicated in renal or hepatic impairment (fatal toxicity reported).
- Monitor: for GI symptoms, myotoxicity, myelosuppression.
What happens
Increased colchicine exposure and an increased risk of fatal toxicity
Interaction Deep Dive
Taking colchicine together with P-gp inhibitors is contraindicated1. When colchicine is used alongside CYP3A4 inhibitors that additionally inhibit P-gp, there is a risk of serious, life-threatening toxicity. Should coadministration of colchicine with a P-gp inhibitor be required, the colchicine dose needs modification, either by lowering the daily amount by 50% to 75% 3 or by decreasing how often it is given. Furthermore, in patients who have renal or hepatic impairment, the combined use of colchicine with P-gp and CYP3A4 inhibitors is contraindicated 3. In such patients with renal and hepatic impairment, pairing these inhibitors with colchicine has led to life-threatening or fatal colchicine toxicity 2.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport of colchicine; inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
Keep taking both medicines exactly as prescribed until you speak with your care team, but raise this combination with them soon. This pairing is flagged as one to avoid because colchicine can accumulate to harmful levels.
- Your team may reduce the colchicine dose (often by 50-75%) or space doses further apart, individualized to you.
- They may monitor you more closely for colchicine side effects.
- Tell your team if you have any kidney or liver problems, since the combination is not recommended in that setting.
- Report muscle pain, weakness, numbness, severe diarrhea, vomiting, or unusual bruising promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Colchicine and Cimetidine together?
Cimetidine can push colchicine to dangerous levels, so this combination is generally avoided; if both are needed your care team will lower or space out the colchicine dose and watch you closely. Do not combine them if you have kidney or liver problems without your doctor's guidance. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Cimetidine 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 Cimetidine interaction managed?
Keep taking both medicines exactly as prescribed until you speak with your care team, but raise this combination with them soon. This pairing is flagged as one to avoid because colchicine can accumulate to harmful levels. Your team may reduce the colchicine dose (often by 50-75%) or space doses further apart, individualized to you. They may monitor you more closely for colchicine side effects. Tel… 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 Cimetidine 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: MITIGARE(R) oral capsules, colchicine oral capsules. Hikma Specialty USA Inc (per FDA), Columbus, OH, 2024. DailyMed
- Hansten PD, Tan MS, Horn JR, et al: Colchicine drug interaction errors and misunderstandings: recommendations for improved evidence-based management. Drug Saf 2023; 46(3):223-242. PubMed
Keep reading about Cimetidine
Keep reading about Colchicine
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