Clindamycin and Erythromycin: 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
Erythromycin
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.
You've been prescribed two antibiotics, erythromycin and clindamycin. Erythromycin can slow down a liver enzyme (called CYP3A4) that helps your body break down certain drugs. Clindamycin is partly handled by that same enzyme, so in theory clindamycin could build up a bit higher in your body. That might make its effects, and its side effects (like stomach upset or diarrhea), a little stronger or last longer.
I want to be honest: this concern is theoretical, meaning it's based on how the drugs work rather than lots of real-world reports. The good news is your care team can manage this easily by adjusting doses if needed and keeping an eye on how you feel.
Effect: Erythromycin is a CYP3A4 inhibitor. Because clindamycin undergoes CYP3A4-mediated metabolism, co-administration may increase clindamycin exposure (AUC/Cmax), potentially prolonging or intensifying both therapeutic and adverse effects (e.g., GI toxicity, C. difficile risk).
- Direction: Increased CYP3A4-substrate (clindamycin) exposure. Neither agent is a prodrug in a way that reverses this.
- Mechanism: Inhibition of CYP3A4.
- Onset: Unspecified.
- Evidence: Theoretical; severity rated major.
- Management: Consider dose adjustment individualized to the patient and monitor for substrate-related adverse effects; drug-concentration monitoring where feasible.
What happens
Increased CYP3A4 substrate exposure and an increased risk of CYP3A4-substrate-related adverse effects
Interaction Deep Dive
When erythromycin is taken together with CYP3A4 substrates, the exposure to those substrates can rise, potentially amplifying or extending both their intended effects and their adverse ones. In patients receiving erythromycin at the same time, consider adjusting the dose and, where feasible, keep a close watch on the drug concentrations of the CYP3A4 substrates123.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by erythromycin
How to manage this interaction
Keep taking both antibiotics exactly as prescribed unless your prescriber tells you otherwise. This interaction can usually be managed.
- Your care team may adjust the dose and individualize it to you.
- They may monitor you more closely for stronger or longer-lasting effects, especially gut side effects like nausea, cramping, or diarrhea.
- Watch for and report severe or watery diarrhea, which can occur with these antibiotics.
Ask your pharmacist or doctor whether both antibiotics are still needed together and what side effects to watch for.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Clindamycin and Erythromycin together?
Erythromycin can slow the breakdown of clindamycin, so clindamycin may build up and its side effects (like GI upset or diarrhea) could be stronger; this concern is theoretical, and your care team can manage it by adjusting the dose and monitoring you. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Clindamycin and Erythromycin 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 Erythromycin interaction managed?
Keep taking both antibiotics exactly as prescribed unless your prescriber tells you otherwise. This interaction can usually be managed. Your care team may adjust the dose and individualize it to you. They may monitor you more closely for stronger or longer-lasting effects, especially gut side effects like nausea, cramping, or diarrhea. Watch for and report severe or watery diarrhea, which can occu… 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 Clindamycin or Erythromycin 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: Erythromycin Lactobionate IV injection lyophilized powder for solution, erythromycin lactobionate IV injection lyophilized powder for solution. Nexus Pharmaceuticals (per DailyMed), Lincolnshire, IL, 2024.
- Product Information: Erythromycin oral delayed-release capsules, erythromycin oral delayed-release capsules. Dr. Reddy's Laboratories Inc. (per DailyMed), Princeton, NJ, 2025. DailyMed
- Product Information: ERYTHROMYCIN ETHYLSUCCINATE oral suspension granule, erythromycin ethylsuccinate oral suspension granule. ANI Pharmaceuticals, Inc (per DailyMed), Baudette, MN, 2025. DailyMed
Keep reading about Erythromycin
Keep reading about Clindamycin
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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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