Colchicine and Nirmatrelvir: 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
Colchicine
Nirmatrelvir
No brand names on record
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.
These two drugs don't mix well. Nirmatrelvir comes packaged with ritonavir (the COVID pill Paxlovid), and ritonavir blocks the enzymes and the pump your body uses to clear colchicine. That means colchicine can build up to much higher levels than intended, which can cause serious and even life-threatening problems like severe diarrhea, muscle weakness, and effects on your blood cells.
The good news is your care team knows exactly how to handle this. Depending on your kidney and liver health, they may pause your colchicine, adjust the dose, or pick a different treatment while you take the COVID medicine. Please don't stop or change anything on your own, just call your pharmacist or doctor and let them guide you.
Mechanism: Nirmatrelvir is co-formulated with ritonavir, a potent CYP3A4 and P-gp inhibitor. Colchicine is a CYP3A4/P-gp substrate, so inhibition markedly increases colchicine exposure and toxicity risk. Neither is a prodrug; this is a direct increase in active drug.
- Direction: increased colchicine AUC/Cmax, dose-dependent toxicity.
- Severity: contraindicated in renal or hepatic impairment (life-threatening).
- Evidence: established.
- Management: Withhold colchicine during and 2 to 3 days after ritonavir (longer with advanced age); consider alternative therapy. In normal renal/hepatic function, reduce dose: gout flare 0.6 mg once then 0.3 mg 1 hr later (no sooner than q3days); prophylaxis 0.3 mg daily or every other day; FMF max 0.6 mg/day.
What happens
Increased colchicine exposure and increased risk of colchicine toxicity
Interaction Deep Dive
Combining colchicine with nirmatrelvir/ritonavir is contraindicated in individuals who have renal or hepatic impairment, given the risk of serious and/or life-threatening reactions2. When possible, colchicine should be held throughout nirmatrelvir/ritonavir therapy and for a further 2 to 3 days after it is stopped (or for a longer period in situations such as advanced patient age). If pausing colchicine temporarily is not clinically appropriate, consider using an alternative concurrent medication or COVID-19 therapy3. Patients with normal renal and hepatic function who are currently taking ritonavir or have taken it within the preceding 14 days require an adjustment to the oral colchicine dose. When treating gout alongside ritonavir, give a single 0.6 mg colchicine dose, then 0.3 mg one hour afterward (not to be repeated sooner than every 3 days). For gout prophylaxis, use 0.3 mg once daily when the planned dose would be 0.6 mg twice daily, and 0.3 mg every other day when the planned dose would be 0.6 mg once daily. For familial Mediterranean fever with concurrent use of a strong CYP3A4 inhibitor, the maximum oral daily dose is 0.6 mg (which may be split as 0.3 mg twice daily)4.
Why it happens (mechanism)
Inhibition of CYP3A4- and P-gp-mediated colchicine metabolism by nirmatrelvir/ritonavir
How to manage this interaction
What your care team may do:
- If you have kidney or liver problems, this combination is avoided because of the risk of serious toxicity.
- They may pause your colchicine during the COVID treatment and for a few days afterward (2 to 3 days, sometimes longer in older adults).
- If pausing isn't practical, they may choose a different COVID treatment or a different medication.
- If your kidneys and liver work normally, your colchicine dose may be lowered and individualized while you are on ritonavir.
What you should do: Keep taking both only as prescribed, and let your pharmacist or prescriber know you take colchicine before starting Paxlovid so they can tailor your plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a study involving 18 patients, taking colchicine 0.6 mg together with ritonavir 100 mg twice daily over 5 days produced increases of 184.4% in colchicine Cmax and 296% in colchicine AUC compared with baseline 1.
Common questions
Can I take Colchicine and Nirmatrelvir together?
Ritonavir (in Paxlovid) can raise colchicine to dangerous levels, so this combo is off-limits if you have kidney or liver problems and needs pausing or dose reduction otherwise. Always clear it with your pharmacist or doctor first. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Nirmatrelvir 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 Nirmatrelvir interaction managed?
What your care team may do: If you have kidney or liver problems, this combination is avoided because of the risk of serious toxicity. They may pause your colchicine during the COVID treatment and for a few days afterward (2 to 3 days, sometimes longer in older adults). If pausing isn't practical, they may choose a different COVID treatment or a different medication. If 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 "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Colchicine or Nirmatrelvir 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 (4)
- Product Information: COLCRYS(TM) oral tablets, colchicine oral tablets. Mutual Pharmaceutical Company, Philadelphia, PA, 2009. DailyMed
- Pfizer Inc: Fact sheet for healthcare providers: Emergency Use Authorization for PAXLOVID(TM). US Food & Drug Administration (FDA). Silver Spring, MD. 2021.
- COVID-19 Treatment Guidelines Panel: Coronavirus disease 2019 (COVID-19) treatment guidelines. National Institutes of Health (NIH). Bethesda, MD. 2023.
- Product Information: NORVIR(R) oral tablets, oral solution, ritonavir oral tablets, oral solution. AbbVie Inc. (per manufacturer), North Chicago, IL, 2016. DailyMed
Keep reading about Colchicine
Keep reading about Nirmatrelvir
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