Drug Interaction Report

Imatinib and Lefamulin: Interaction Details

A pharmacist-reviewed analysis of the Imatinib and Lefamulin interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Imatinib

Gleevec Imkeldi
+

Lefamulin

Xenleta Xenleta®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 79 documented Imatinib interactions, 73 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

Increased lefamulin exposure and an increased risk of lefamulin-related adverse reactions

Interaction Deep Dive

Avoid concomitant use of lefamulin with strong and moderate CYP3A4 inhibitors, as it may increase lefamulin exposure and may also increase risk of lefamulin-related adverse reactions. In a drug interaction study, oral ketoconazole (strong inhibitor) increased the mean lefamulin AUC (0 to inf) and Cmax by 31% and 6%, respectively, when administered concomitantly with lefamulin injection. Additionally, oral ketoconazole (strong inhibitor) increased the lefamulin AUC (0 to inf) and Cmax by 165% and 58%, respectively, when administered inf concomitantly with oral lefamulin1.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated metabolism of lefamulin

Literature reports

1 report — tap to read

a) In a drug interaction study, oral ketoconazole (strong inhibitor) increased the mean lefamulin AUC (0 to inf) and Cmax by 31% and 6%, respectively, when administered concomitantly with lefamulin injection. Additionally, oral ketoconazole (strong inhibitor) increased the lefamulin AUC (0 to inf) and Cmax by 165% and 58%, respectively, when administered inf concomitantly with oral lefamulin 1.

Common questions

Can I take Imatinib and Lefamulin together?

Increased lefamulin exposure and an increased risk of lefamulin-related adverse reactions Always confirm with your pharmacist or prescriber before making any change.

How serious is the Imatinib and Lefamulin 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 strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Imatinib or Lefamulin 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)

  1. Product Information: XENLETA(R) oral tablets, intravenous injection, lefamulin oral tablets, intravenous injection. Nabriva Therapeutics US Inc (per FDA), King of Prussia, PA, 2021. DailyMed
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Imatinib

Keep reading about Imatinib

All Imatinib interactions (79)
Also serious with: Finerenone Olaparib Amlodipine Neratinib
Lefamulin

Keep reading about Lefamulin

All Lefamulin interactions (443) Lefamulin drug information
Also serious with: Lomitapide Ketoconazole Levoketoconazole Ivosidenib
Beyond drug–drug

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:

Imatinib + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia St. John's Wort + 145 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.