Lefamulin and Elexacaftor: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Lefamulin
Elexacaftor
No brand names on record
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.
What happens
Increased elexacaftor exposure
Interaction Deep Dive
The concomitant administration of elexacaftor/tezacaftor/ivacaftor and a moderate CYP3A inhibitor may result in significantly increased elexacaftor, tezacaftor and ivacaftor exposure, and dose adjustments are required. Alternate daily dosing starting with 2 tablets (elexacaftor 100 mg/tezacaftor 50 mg/ivacaftor 75 mg per tablet) orally in the morning on day 1, then ivacaftor 150 mg orally in the morning on day 2 (do not take any ivacaftor evening doses). Continue alternating these morning doses during concomitant therapy1.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism of elexacaftor
Literature reports
2 reports — tap to read
a) Dose simulation studies suggested that coadministration with moderate CYP3A inhibitors may increase elexacaftor and tezacaftor AUC by approximately 1.9- to 2.3-fold and 2.1-fold, respectively 1.
b) Coadministration of ivacaftor 150 mg orally twice daily with moderate CYP3A inhibitor fluconazole 400 mg orally x 1 dose on day 1, followed by 200 mg once daily resulted in a 2.95-fold increase in ivacaftor exposure and a 2.47-fold increase in Cmax 1.
Common questions
Can I take Lefamulin and Elexacaftor together?
Increased elexacaftor exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lefamulin and Elexacaftor 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 "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Lefamulin or Elexacaftor 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: TRIKAFTA(R) oral tablets oral granules, elexacaftor, tezacaftor, ivacaftor oral tablets oral granules; ivacaftor oral tablets oral granules. Vertex Pharmaceuticals Incorporated (per FDA), Boston, MA, 2024. DailyMed
Keep reading about Lefamulin
Keep reading about Elexacaftor
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist