Clindamycin and Tocilizumab: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 1, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Clindamycin
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. Tocilizumab (Actemra) can calm down inflammation in your body, and when it does, it can speed up a liver enzyme called CYP3A4. Clindamycin is partly broken down by that same enzyme. So when you use both, your body may clear clindamycin a little faster, which could make the antibiotic less effective at fighting your infection.
The good news is this is manageable. Your care team can watch how well your infection is responding and adjust things if needed. Don't stop or change either medicine on your own. Just let your pharmacist or doctor know you take both so they can keep an eye on how you're doing.
Mechanism: Tocilizumab normalizes IL-6-mediated suppression of CYP3A4, effectively inducing CYP3A4 activity. Clindamycin is a CYP3A4 substrate, so coadministration may increase its metabolism and reduce systemic exposure, potentially lowering antibacterial efficacy.
- Direction: reduced clindamycin exposure / effect (induction)
- Evidence: probable; documented decreases in omeprazole, simvastatin, dextromethorphan AUC after a single tocilizumab dose
- Onset: develops over ~1 week; effect may persist several weeks after discontinuation
- Management: monitor therapeutic response (clinical resolution of infection); consider dose or regimen adjustment individualized by the team on initiation/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 substrate's exposure. 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 that substrate as needed when tocilizumab is started or stopped. Tocilizumab's impact on CYP450 enzyme activity can continue for several weeks following discontinuation of the drug. Exercise caution when giving tocilizumab alongside CYP3A4 substrate medications such as oral contraceptives, lovastatin, atorvastatin, and others, where a loss of effectiveness would be undesirable123.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism by tocilizumab
How to manage this interaction
Keep taking both as prescribed unless your care team tells you otherwise.
- Your team may watch more closely to make sure the clindamycin is working and your infection is improving.
- The clindamycin dose or regimen may need to be adjusted and individualized by your care team, especially when tocilizumab is started or stopped.
- Remember this effect can last for several weeks after tocilizumab is stopped, so timing matters.
- Tell your pharmacist or prescriber if your infection is not getting better or seems to be coming back.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) Clinical studies showed that omeprazole, which is metabolized by CYP2C19 and CYP3A4, and simvastatin, which is metabolized by CYP3A4, had reductions in exposure of up to 28% and 57%, respectively, one week after a single dose of tocilizumab 13.
b) In drug interaction studies involving 13 RA patients given 30 mg dextromethorphan (a substrate of CYP2D6 and CYP3A4), dextromethorphan exposure was similar to that seen in healthy subjects. Exposure to its metabolite dextrorphan (a CYP3A4 substrate), however, was only a portion of what was observed in healthy subjects. One week after a single infusion of tocilizumab (8 mg per kg), dextromethorphan exposure fell by roughly 5%. A greater reduction (29%) in dextrorphan levels was observed following the tocilizumab infusion 2.
Common questions
Can I take Clindamycin and Tocilizumab together?
Tocilizumab can speed up how your body breaks down clindamycin, which may make the antibiotic work less well; keep taking both as prescribed and let your care team monitor your response so they can adjust the dose if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Clindamycin and Tocilizumab 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 Clindamycin and Tocilizumab interaction managed?
Keep taking both as prescribed unless your care team tells you otherwise. Your team may watch more closely to make sure the clindamycin is working and your infection is improving. The clindamycin dose or regimen may need to be adjusted and individualized by your care team, especially when tocilizumab is started or stopped. Remember this effect can last for several weeks after tocilizumab is stoppe… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Clindamycin or Tocilizumab 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 Clindamycin
Keep reading about Tocilizumab
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.
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