Clindamycin and Lazertinib: 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
Lazertinib
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. Lazertinib (Lazcluze) is a cancer medicine that can slow down a liver enzyme called CYP3A4. Clindamycin, your antibiotic, is partly broken down by that same enzyme. So when you take them together, clindamycin may build up a little more in your body than usual, which could raise the chance of side effects like stomach upset, diarrhea, or a change in your gut bacteria.
The good news is this is very manageable. Please keep taking both exactly as prescribed and let your care team know you're on both. They can watch you a bit more closely and adjust things if needed. Call your doctor if you get worse than usual diarrhea or belly pain.
Mechanism: Lazertinib inhibits CYP3A4, reducing metabolism of CYP3A4 substrates. In the index study it raised midazolam Cmax ~1.4-fold and AUC ~1.5-fold. Clindamycin is a CYP3A4 substrate, so exposure may modestly increase.
- Direction: increased clindamycin exposure and adverse-effect risk (neither drug is a prodrug here).
- Severity/evidence: rated major, mechanism probable; onset unspecified.
- Magnitude: a ~1.4-1.5-fold change is expected based on midazolam probe data.
- Management: monitor for clindamycin-related adverse reactions (GI intolerance, C. difficile-associated diarrhea); dose may need individualization by the care team.
What happens
Increased CYP3A4 substrate with NTI exposure and an increased risk of CYP3A4 substrates with NTI-related adverse reactions
Interaction Deep Dive
Taking lazertinib together with CYP3A4 substrates that have a narrow therapeutic index (NTI) can raise the exposure of those NTI substrates and may heighten the likelihood of adverse reactions linked to them. When lazertinib was given concurrently, the Cmax of midazolam (a CYP3A4 substrate) rose by 1.4-fold and its AUC by 1.5-fold. Watch for adverse reactions tied to a CYP3A4 substrate in cases where even small shifts in concentration could produce serious adverse reactions1.
Why it happens (mechanism)
Inhibition of CYP3A4-substrate metabolism by lazertinib
How to manage this interaction
What your care team may do:
- Keep you on both medicines but monitor you more closely for clindamycin side effects.
- Watch for gut-related problems such as significant diarrhea or abdominal pain.
- Adjust and individualize your dosing if that becomes appropriate.
What you should do:
- Keep taking both exactly as prescribed unless your prescriber tells you otherwise.
- Tell your pharmacist and doctor you are on both drugs.
- Report new or worsening diarrhea, stomach pain, or feeling unwell so they can respond promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) When lazertinib was given together with midazolam (a CYP3A4 substrate), the midazolam Cmax rose by 1.4-fold and its AUC rose by 1.5-fold 1.
Common questions
Can I take Clindamycin and Lazertinib together?
Lazertinib can slow the breakdown of clindamycin, modestly raising its levels and the chance of side effects like diarrhea. Keep taking both as prescribed and tell your care team so they can monitor you. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Clindamycin and Lazertinib 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 Lazertinib interaction managed?
What your care team may do: Keep you on both medicines but monitor you more closely for clindamycin side effects. Watch for gut-related problems such as significant diarrhea or abdominal pain. Adjust and individualize your dosing if that becomes appropriate. What you should do: Keep taking both exactly as prescribed unless your prescriber tells you otherwise. Tell your pharmacist and doctor you ar… 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 Lazertinib 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 (1)
- Product Information: LAZCLUZE™ oral tablets, lazertinib oral tablets. Janssen Biotech, Inc. (Per FDA), Horsham, PA, 2025. DailyMed
Keep reading about Clindamycin
Keep reading about Lazertinib
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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