Drug Interaction Report

Sonidegib and Letermovir Injection: Interaction Details

A pharmacist-reviewed analysis of the Sonidegib and Letermovir Injection 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

Sonidegib

Odomzo Odomzo®
+

Letermovir Injection

Prevymis Prevymis®
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 12 documented Sonidegib interactions, 12 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 sonidegib exposure

Interaction Deep Dive

The concomitant use of sonidegib, a CYP3A substrate, with a moderate CYP3A inhibitor may result in increased sonidegib exposure and increase the risk of adverse effects1. Based on projections from coadministration of sonidegib with ketoconazole, a strong CYP3A inhibitor, the AUC of sonidegib would increase 1.79-fold if sonidegib 200 mg once daily is coadministered with a moderate CYP3A inhibitor for 14 days and a 2.79-fold increase if coadministered for 4 months 2. Therefore, it is recommended that coadministration of sonidegib with a moderate CYP3A inhibitor be avoided. If coadministration cannot be avoided, concurrent use should be limited to less than 14 days and patients should be monitored closely for adverse reactions particularly musculoskeletal toxicity 1.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated metabolism of sonidegib

Literature reports

1 report — tap to read

a) In a pharmacokinetic study of 31 healthy volunteers, the mean AUC(0 to 10 days) increased 2.25-fold and the Cmax increased 1.49-fold with sonidegib 800 mg single-dose administered 5 days after initiating oral ketoconazole (a strong CYP3A inhibitor) 200 mg twice daily, compared with a single dose of sonidegib alone. Based on pharmacokinetic modeling projections, the mean AUC(0 to 24 hours) and Cmax of sonidegib would increase 1.79-fold and 1.64-fold, respectively, if sonidegib 200 mg once daily is coadministered to cancer patients with erythromycin (a moderate CYP3A inhibitor) for 14 days, and 2.79-fold and 2.43-fold, respectively, if coadministered for 4 months 2.

Common questions

Can I take Sonidegib and Letermovir Injection together?

Increased sonidegib exposure Always confirm with your pharmacist or prescriber before making any change.

How serious is the Sonidegib and Letermovir Injection 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 Sonidegib or Letermovir Injection 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)

  1. Product Information: ODOMZO(R) oral capsules, sonidegib oral capsules. Novartis Pharmaceuticals (per FDA), East Hanover, NJ, 2015. DailyMed
  2. Einolf HJ, Zhou J, Won C, et al: A physiologically-based pharmacokinetic modeling approach to predict drug-drug interactions of sonidegib (LDE225) with perpetrators of CYP3A in cancer patients. Drug Metab Dispos 2017; 45(4):361-374. PubMed
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Sonidegib

Keep reading about Sonidegib

All Sonidegib interactions (12) Sonidegib drug information
Also serious with: Mitapivat Lanreotide Injection Lefamulin Ketoconazole Topical
Letermovir Injection

Keep reading about Letermovir Injection

All Letermovir Injection interactions (346) Letermovir Injection drug information
Also serious with: Lomitapide Pimozide Dihydroergotamine Bromocriptine

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