Colchicine and Interferon Alfa-2A: 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
Interferon Alfa-2A
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.
If you're taking interferon alfa-2a to treat a virus like hepatitis C, adding colchicine (often used for gout) may make the interferon work less well. In a study of 65 people, folks who took both drugs together had a weaker antiviral response than those on interferon alone. In fact, the results were disappointing enough that researchers stopped the trial early.
We don't fully understand why this happens, but colchicine seems to blunt what the interferon is trying to do. The good news is this is very manageable. Please don't stop or change anything on your own. Just talk with your doctor or pharmacist so they can pick the safest plan for you.
Effect: Reduced antiviral efficacy of interferon alfa-2a when co-administered with colchicine (pharmacodynamic antagonism).
- Direction: Colchicine diminishes interferon alfa-2a's therapeutic response; neither agent's blood level is the concern, this is a PD effect.
- Mechanism: Unknown; colchicine may inhibit interferon synthesis or effectiveness.
- Evidence: Probable. A 65-patient chronic HCV trial showed a lower response with combination therapy vs interferon monotherapy, halted early.
- Onset: Delayed.
- Management: Avoid concomitant use. If colchicine is clinically necessary, coordinate alternatives and monitor virologic/treatment response closely.
What happens
Decreased interferon alfa-2A effectiveness
Interaction Deep Dive
In a clinical trial involving 65 patients who had chronic hepatitis C, the antiviral response was diminished when colchicine was combined with interferon alfa-2A, relative to interferon alfa-2A given on its own2. The rationale for investigating colchicine was the hypothesis that its antifibrotic properties might enhance the antiviral action of interferon alfa-2A. Contrary to this expectation, the combination regimen produced a lower patient response, which led to the trial being terminated early.
Why it happens (mechanism)
An unknown mechanism; colchicine may inhibit the synthesis or effectiveness of interferons
How to manage this interaction
Here is how a care team usually handles this:
- Avoiding the combination is the preferred approach, since colchicine appears to weaken how well interferon alfa-2a fights the virus.
- Your team may choose an alternative for whatever the colchicine was treating, or adjust your plan so the two don't overlap.
- If you do need both, your team may monitor your treatment response more closely.
What you should do: keep taking both exactly as prescribed for now, and reach out to your pharmacist or prescriber to let them know you're on both. Don't stop either one on your own.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In an open-label, randomized, controlled, blinded clinical trial involving 65 patients with chronic hepatitis C, giving colchicine together with interferon alfa-2A lowered the antiviral and biochemical response compared with interferon alfa-2A given alone. Patients were treated with interferon alfa-2A 6 million units (MU) subcutaneously three times weekly (TIW) for 6 months, then 3 MU TIW for 6 months, either with or without colchicine 1 milligram orally 6 days per week. The colchicine regimen was planned to continue for 3 years. At the 18-month interim analysis, the trial was halted because of the diminished response among patients on combination therapy. A significantly (p less than 0.05) greater number of patients receiving interferon alfa-2A alone attained a biochemical (normalization of ALT) and virologic response at 6, 12, and 18 months. A larger number of patients on combination therapy experienced a biochemical relapse 1.
Common questions
Can I take Colchicine and Interferon Alfa-2A together?
Taking colchicine with interferon alfa-2a can make the interferon work less well against the virus, so the two are generally best avoided. Ask your pharmacist or doctor to review your regimen before making any changes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Colchicine and Interferon Alfa-2A interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Colchicine and Interferon Alfa-2A interaction managed?
Here is how a care team usually handles this: Avoiding the combination is the preferred approach, since colchicine appears to weaken how well interferon alfa-2a fights the virus. Your team may choose an alternative for whatever the colchicine was treating, or adjust your plan so the two don't overlap. If you do need both, your team may monitor your treatment response more closely. What you should… 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 Interferon Alfa-2A 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 (2)
- Angelico M, Cepparulo M, Barlattani A, et al: Unfavourable effects of colchicines in combination with interferon-alpha in the treatment of chronic hepatitis C. Aliment Pharmacol Ther 2000; 14:1459-1467.
- Angelico M, Cepparulo M, Barlattani A, et al: Unfavourable effects of colchicine in combination with interferon-alpha in the treatment of chronic hepatitis C. Aliment Pharmacol Ther 2000; 14:1459-1467.
Keep reading about Colchicine
Keep reading about Interferon Alfa-2A
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