Colchicine and Letermovir: 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
Letermovir
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.
Letermovir (Prevymis) can cause colchicine to build up in your body. Letermovir slows down an enzyme that normally helps break colchicine down. When that happens, colchicine levels can climb higher than intended. That matters because too much colchicine can be very dangerous, even life-threatening, causing severe stomach upset, muscle weakness, and blood problems.
The good news is that this is very manageable. Your care team can lower your colchicine dose or space it out further, and watch you closely for any warning signs. Please don't stop or change either medicine on your own. Just talk with your pharmacist or doctor so they can tailor your colchicine dose safely.
Mechanism: Letermovir is a moderate CYP3A4 inhibitor; colchicine is a CYP3A4 (and P-gp) substrate. Inhibition reduces colchicine clearance, increasing plasma exposure and the risk of dose-dependent, potentially fatal toxicity.
Direction: increased colchicine effect/exposure. Evidence: theoretical. Severity: major.
- Avoid in renal or hepatic impairment.
- If used within 14 days of letermovir, reduce colchicine dose/frequency.
- Gout flare: 1.2 mg once, repeat no sooner than 3 days.
- Prophylaxis: 0.6 mg BID to 0.6 mg daily; 0.6 mg daily to 0.3 mg daily.
- FMF: max 1.2 mg/day.
- Monitor for toxicity; discontinue colchicine immediately if suspected.
What happens
Increased colchicine exposure and an increased risk of fatal toxicity
Interaction Deep Dive
Do not use colchicine together with a moderate CYP3A4 inhibitor, because this combination can raise colchicine plasma levels and lead to fatal colchicine toxicity. When coadministration cannot be avoided, modify the colchicine dose by lowering either the total daily amount or how often it is taken3. If the two are used together, or within a 14 day window, the colchicine regimen for a gout flare should be changed from the usual 1.2 mg (2 tablets) followed one hour later by 0.6 mg (1 tablet) to a single 1.2 mg (2 tablets) dose, with any repeat dose delayed until at least 3 days later. For gout flare prophylaxis, reduce the colchicine dose from 0.6 mg twice daily to 0.6 mg once daily, or from 0.6 mg once daily to 0.3 mg once daily. For patients with familial Mediterranean fever who must take colchicine alongside a moderate CYP3A4 inhibitor, the colchicine total daily dose should not exceed 1.2 mg (which may be split as 0.6 mg twice daily). Watch for signs and symptoms indicating colchicine toxicity, and stop colchicine right away if it is suspected2. In addition, in patients who have renal or hepatic impairment, avoid using colchicine concurrently with moderate CYP3A4 inhibitors1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of colchicine
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Because letermovir can raise colchicine levels, your team will typically:
- Lower your colchicine dose or take it less often. For a gout flare this may mean a single reduced dose with any repeat delayed by at least 3 days; for prevention, a lower daily dose.
- Watch you closely for colchicine toxicity and stop colchicine right away if it is suspected.
- Avoid this combination if you have kidney or liver problems.
Tell your pharmacist or doctor about any diarrhea, vomiting, muscle weakness or pain, numbness, or unusual tiredness. Your colchicine dose can be individualized to keep you safe.
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 Letermovir together?
Letermovir can push colchicine levels up and cause serious toxicity, so your care team will usually reduce the colchicine dose or frequency and monitor you closely. Report any diarrhea, vomiting, or muscle weakness right away. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Letermovir 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 Letermovir interaction managed?
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Because letermovir can raise colchicine levels, your team will typically: Lower your colchicine dose or take it less often. For a gout flare this may mean a single reduced dose with any repeat delayed by at least 3 days; for prevention, a lower daily dose. Watch you closely for colchicine toxicity and stop… 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 Letermovir 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 Letermovir
Keep reading about Colchicine
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