Clarithromycin and Clindamycin: 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
Clarithromycin
Clindamycin
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.
Let's talk about taking clarithromycin (Biaxin) and clindamycin (Cleocin) together. Clarithromycin can slow down a liver enzyme (called CYP3A4) that helps break down clindamycin. When that happens, clindamycin can build up a bit more in your body, which could mean a higher chance of side effects like stomach upset or diarrhea.
I want to be honest with you: this concern is mostly theoretical, meaning it's based on how the drugs work rather than lots of real-world reports. Please don't stop either one on your own. Your care team can manage this easily by adjusting doses if needed and keeping a closer eye on how you feel.
Effect: Clarithromycin, a strong CYP3A4 inhibitor, may reduce metabolism of clindamycin (a CYP3A4 substrate), increasing clindamycin plasma exposure and theoretical toxicity risk.
- Mechanism: Inhibition of CYP3A4-mediated clindamycin metabolism.
- Direction: Increased clindamycin exposure (neither agent is dependent on activation, so effects are enhanced).
- Evidence: Theoretical; magnitude not quantified.
- Onset: Unspecified.
- Management: Use caution; consider dose adjustment where feasible and monitor clinically (e.g., GI toxicity) since routine clindamycin levels are not standard.
What happens
Increased exposure of CYP3A4 substrate and risk for toxicity
Interaction Deep Dive
Exercise caution when clarithromycin, which acts as a strong CYP3A4 inhibitor, is given together with agents that undergo extensive CYP3A4 metabolism, since this pairing can raise plasma levels of the CYP3A4 substrate and heighten the potential for toxicity12. Where feasible, dose modifications should be considered, along with careful monitoring of serum levels of drugs that rely mainly on CYP3A4 for their metabolism1.
Why it happens (mechanism)
Inhibition of CYP3A4-substrate metabolism by clarithromycin
How to manage this interaction
Here's how a care team typically handles this combination:
- Keep taking both as prescribed unless your prescriber tells you otherwise.
- Your clindamycin dose may need to be adjusted and individualized by your care team while you're on clarithromycin.
- Your team may monitor you more closely for signs of clindamycin building up, such as significant diarrhea or stomach discomfort.
Let your pharmacist or doctor know you're taking both, and report any bothersome side effects (especially persistent or severe diarrhea). This is very manageable with good communication.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) In the drug interaction studies, giving clarithromycin 500 mg every 8 hours together with omeprazole 40 mg daily to healthy adult subjects led to higher steady-state plasma concentrations of clarithromycin [Cmax, AUC (0 to 24), and half-life rose by 30%, 89%, and 34%, respectively] 2.
b) Concurrent administration of omeprazole raised the plasma levels of clarithromycin and 14-OH clarithromycin. For clarithromycin, the mean Cmax was 10% higher, the mean Cmin was 27% higher, and the mean AUC (0 to 8) was 15% higher when clarithromycin was given with omeprazole compared with clarithromycin given by itself. Comparable findings were observed for 14-OH clarithromycin, with the mean Cmax 45% higher, the mean Cmin 57% higher, and the mean AUC (0 to 8) 45% higher 2.
Common questions
Can I take Clarithromycin and Clindamycin together?
Clarithromycin can raise clindamycin levels by slowing its breakdown, so watch for more side effects like diarrhea; keep taking both as prescribed and let your care team adjust the dose or monitor you if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Clarithromycin and Clindamycin 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 Clarithromycin and Clindamycin interaction managed?
Here's how a care team typically handles this combination: Keep taking both as prescribed unless your prescriber tells you otherwise. Your clindamycin dose may need to be adjusted and individualized by your care team while you're on clarithromycin. Your team may monitor you more closely for signs of clindamycin building up, such as significant diarrhea or stomach discomfort. Let your pharmacist or… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Clarithromycin or Clindamycin 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)
- Product Information: BIAXIN(R) XL Filmtab(R) oral extended-release tablets, clarithromycin oral extended-release tablets. AbbVie Inc (per FDA), North Chicago, IL, 2018. DailyMed
- Product Information: VOQUEZNA(R) TRIPLE PAK(R) oral kit, vonoprazan oral tablets, amoxicillin oral capsules, clarithromycin oral tablets kit. Phathom Pharmaceuticals (per FDA), Buffalo Grove, IL, 2024. DailyMed
Keep reading about Clarithromycin
Keep reading about Clindamycin
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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