Drug Interaction Report

Elinzanetant and Letermovir Injection: Interaction Details

A pharmacist-reviewed analysis of the Elinzanetant 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

Letermovir Injection

Prevymis Prevymis®
+

Elinzanetant

Lynkuet
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
LinkedIn
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 35 documented Elinzanetant interactions, 35 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 elinzanetant exposure and an increased risk of elinzanetant-related adverse reactions

Interaction Deep Dive

Concomitant use of elinzanetant (CYP3A4 substrate) with moderate CYP3A4 inhibitors may increase elinzanetant exposure, which may increase the risk of elinzanetant adverse reactions. Hence reduce elinzanetant dosage to 60 mg (one capsule) orally once daily at bedtime. After discontinuation of the moderate CYP3A4 inhibitor (after 3 to 5 half-lives of the inhibitor), administer elinzanetant at the usual dosage of 120 mg once daily. In drug interaction studies, coadministration of elinzanetant 120 mg with erythromycin (moderate CYP3A4 inhibitor) predicted to increase elinzanetant Cmax and AUC by 2.0-fold and 3.0-fold, respectively. PBPK (physiologically based pharmacokinetic) predictions after coadministration of 60 mg elinzanetant with erythromycin showed a 1.4-fold increase of elinzanetant AUC and no increase for Cmax when compared to 120 mg, the regular recommended elinzanetant dosage1.

Why it happens (mechanism)

Inhibition of CYP3A4-mediated metabolism of elinzanetant

Literature reports

1 report — tap to read

a) In drug interaction studies, coadministration of elinzanetant 120 mg with erythromycin (moderate CYP3A4 inhibitor) predicted to increase elinzanetant Cmax and AUC by 2.0-fold and 3.0-fold, respectively. PBPK (physiologically based pharmacokinetic) predictions after coadministration of 60 mg elinzanetant with erythromycin showed a 1.4-fold increase of elinzanetant AUC and no increase for Cmax when compared to 120 mg, the regular recommended elinzanetant dosage 1.

Common questions

Can I take Elinzanetant and Letermovir Injection together?

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

How serious is the Elinzanetant 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 Elinzanetant 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 (1)

  1. Product Information: LYNKUET® oral capsules, elinzanetant oral capsules. Bayer HealthCare Pharmaceuticals Inc (per Manufacturer), Whippany, NJ, 2025. DailyMed
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