Belzutifan and Colchicine: 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
Belzutifan
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.
Belzutifan (Welireg) can speed up the enzyme that your body uses to break down colchicine. When colchicine is cleared faster, there may be less of it in your blood, which could make it work less well for gout or pericarditis.
Right now this is a predicted concern based on how belzutifan behaves with similar drugs, not something proven with colchicine itself. Please don't change either medicine on your own. Your care team can keep an eye on how well your colchicine is controlling your symptoms and adjust things if needed. A quick chat with your pharmacist or doctor is the best next step.
Mechanism: Belzutifan is a CYP3A4 inducer; colchicine is a CYP3A4 (and P-gp) substrate. Induction is expected to increase colchicine clearance, lowering its exposure (AUC/Cmax) and potentially its efficacy.
- Direction: reduced colchicine effect (not toxicity).
- Magnitude: theoretical for colchicine; belzutifan decreased midazolam AUC ~40% (up to ~70% in dual UGT2B17/CYP2C19 poor metabolizers).
- Onset: unspecified.
- Evidence: theoretical.
Management: Avoid where possible. If combined, monitor therapeutic response and adjust/individualize the colchicine dose as needed; effect may be greater in dual poor metabolizers.
What happens
Reduced CYP3A4 substrates with NTI exposure and reduced efficacy of CYP3A4 substrates with NTI
Interaction Deep Dive
Do not give belzutifan together with sensitive CYP3A4 substrates in cases where even a small drop in their concentration could cause the substrate to fail therapeutically. When such coadministration is unavoidable, raise the dose of the sensitive CYP3A4 substrate as necessary. Giving belzutifan alongside CYP3A4 substrates may lower the exposure of CYP3A4 substrates with NTI, potentially diminishing the effectiveness of these substrates. This effect may be greater in patients who are poor metabolizers of both UGT2B17 and CYP2C19. When belzutifan was administered with midazolam (a sensitive CYP3A4 substrate), the midazolam AUC fell by 40% and the Cmax by 34%. In patients with elevated belzutifan concentrations (for example, dual poor metabolizers), midazolam AUC is projected to decline by as much as 70%1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism by belzutifan
How to manage this interaction
Keep taking both medications exactly as prescribed unless your care team tells you otherwise.
- Your team may try to avoid this combination when a small drop in colchicine could matter.
- If both are needed, your colchicine dose may be adjusted and individualized by your prescriber.
- They may monitor you more closely to be sure the colchicine is still controlling your symptoms.
What to do: tell your pharmacist and doctor you take both. Let them know if your gout or other symptoms seem to return or worsen, since that could signal reduced effect.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) When belzutifan 120 mg once daily was given together with midazolam (a sensitive CYP3A4 substrate), the midazolam AUC fell by 40% and the Cmax fell by 34%. In patients with higher belzutifan concentrations (for example, dual poor metabolizers), the midazolam AUC is projected to decline by as much as 70% 1.
Common questions
Can I take Belzutifan and Colchicine together?
Belzutifan may speed up how your body clears colchicine, which could make the colchicine work less well; keep taking both as prescribed and have your care team monitor and adjust the dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Belzutifan and Colchicine 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 Belzutifan and Colchicine interaction managed?
Keep taking both medications exactly as prescribed unless your care team tells you otherwise. Your team may try to avoid this combination when a small drop in colchicine could matter. If both are needed, your colchicine dose may be adjusted and individualized by your prescriber. They may monitor you more closely to be sure the colchicine is still controlling your symptoms. What to do: tell your ph… 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 Belzutifan or Colchicine 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 (1)
- Product Information: WELIREG(R) oral tablets, belzutifan oral tablets. Merck Sharp & Dohme LLC (per manufacturer), Rahway, NJ, 2025. DailyMed
Keep reading about Belzutifan
Keep reading about Colchicine
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