Venetoclax and Letermovir Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Venetoclax
Letermovir Injection
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 venetoclax exposure and an increased risk of venetoclax toxicities including the risk of tumor lysis syndrome
Interaction Deep Dive
Concomitant use of venetoclax with moderate CYP3A inhibitors may increase exposure of venetoclax and increase risk of venetoclax toxicities including the risk of tumor lysis syndrome. If a moderate CYP3A inhibitor is required, reduce the venetoclax dose by at least 50%. Two to 3 days after discontinuation of a concurrent CYP3A inhibitor, resume the venetoclax dosage that was used prior to initiating the inhibitor1.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism of venetoclax
Common questions
Can I take Venetoclax and Letermovir Injection together?
Increased venetoclax exposure and an increased risk of venetoclax toxicities including the risk of tumor lysis syndrome Always confirm with your pharmacist or prescriber before making any change.
How serious is the Venetoclax 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 Venetoclax 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)
- Product Information: VENCLEXTA(R) oral tablets, venetoclax oral tablets. AbbVie Inc (per FDA), North Chicago, IL, 2022. DailyMed
Keep reading about Venetoclax
Keep reading about Letermovir Injection
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