Tocilizumab 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
Colchicine
Tocilizumab
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.
Here's what's going on. Colchicine is broken down in your body by a liver enzyme called CYP3A4. Tocilizumab can speed up that enzyme, which means your body may clear colchicine faster. When that happens, there may be less colchicine in your system, so it might not control your gout or inflammation as well as usual.
The good news is this is very manageable. Your care team can watch how well your colchicine is working and adjust your dose if needed, especially when you start or stop tocilizumab. Keep taking both exactly as prescribed, and let your pharmacist or doctor know if your symptoms come back or feel worse.
Mechanism: Tocilizumab, via IL-6 suppression, can reverse cytokine-mediated downregulation of CYP450 enzymes, effectively inducing CYP3A4. Colchicine is a CYP3A4 substrate, so its metabolism may increase.
Direction/effect: Reduced colchicine exposure (AUC/Cmax) and potentially reduced efficacy. Clinical studies showed decreased exposure of CYP3A4 substrates (omeprazole, simvastatin, dextromethorphan) about one week after a single tocilizumab dose.
- Onset: Delayed; effect may persist several weeks after tocilizumab discontinuation.
- Evidence: Probable; severity major.
- Management: Monitor therapeutic response; adjust colchicine dose upon initiation or discontinuation of tocilizumab.
What happens
Reduced CYP3A4 substrate with NTI exposure and reduced efficacy of CYP3A4 substrate with NTI
Interaction Deep Dive
Taking tocilizumab together with a CYP3A4 substrate that has a narrow therapeutic index (NTI) can lower the exposure of that substrate. Clinical trials demonstrated that CYP3A4 substrates (omeprazole, simvastatin, and dextromethorphan) had reduced exposure one week after a single tocilizumab dose. For patients receiving a CYP3A4 NTI substrate, monitor the therapeutic response or drug levels and adjust the individual dose of the CYP3A4 NTI substrate as required when tocilizumab is started or stopped. Tocilizumab's influence on CYP450 enzyme activity can continue for several weeks following cessation of treatment. Exercise caution when tocilizumab is given alongside CYP3A4 substrate medications such as oral contraceptives, lovastatin, atorvastatin, and similar agents, where a reduction in effectiveness would be unwanted123.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism by tocilizumab
How to manage this interaction
The key message: keep taking both medications as prescribed. This interaction is something your care team can handle by watching how well your colchicine is working.
- Your colchicine dose may need to be adjusted and individualized by your care team when you start or stop tocilizumab.
- The effect of tocilizumab can last several weeks after stopping it, so monitoring may continue during that time.
- Tell your pharmacist or doctor if your gout or inflammation symptoms return or worsen, since that could signal your colchicine is less effective.
Do not change either dose on your own; let your prescriber guide any adjustments.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) In clinical trials, omeprazole, which is metabolized by CYP2C19 and CYP3A4, and simvastatin, which is metabolized by CYP3A4, demonstrated reductions in exposure of up to 28% and 57%, respectively, one week after a single dose of tocilizumab 13.
b) In drug interaction studies, among 13 RA patients given 30 mg of dextromethorphan (a substrate of CYP2D6 and CYP3A4), dextromethorphan exposure was similar to that seen in healthy subjects. In contrast, exposure to its metabolite, dextrorphan (a CYP3A4 substrate), was only a fraction of what was observed in healthy subjects. One week after a single infusion of tocilizumab (8 mg per kg), dextromethorphan exposure declined by roughly 5%. However, a greater reduction (29%) in dextrorphan levels was seen following the tocilizumab infusion 2.
Common questions
Can I take Tocilizumab and Colchicine together?
Tocilizumab may lower colchicine levels and make it work less well, so your care team may monitor your response and adjust your colchicine dose when tocilizumab is started or stopped. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tocilizumab 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 Tocilizumab and Colchicine interaction managed?
The key message: keep taking both medications as prescribed. This interaction is something your care team can handle by watching how well your colchicine is working. Your colchicine dose may need to be adjusted and individualized by your care team when you start or stop tocilizumab. The effect of tocilizumab can last several weeks after stopping it, so monitoring may continue during that time. 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 Tocilizumab 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 (3)
- Product Information: AVTOZMA(R) intravenous, subcutanous injection, tocilizumab-anoh intravenous, subcutanous injection. CELLTRION USA, Inc. Jersey City, NJ, 2025. DailyMed
- Product Information: TYENNE(R) intravenous, subcutaneous injection, tocilizumab-aazg intravenous, subcutaneous injection. Fresenius Kabi USA, LLC (Per FDA), Lake Zurich, IL, 2024. DailyMed
- Product Information: TOFIDENCE(TM) intravenous injection, tocilizumab-bavi intravenous injection. Biogen MA Inc (per FDA), Cambridge, MA, 2023. DailyMed
Keep reading about Colchicine
Keep reading about Tocilizumab
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