Abemaciclib and Smallpox Monkeypox Vaccine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Abemaciclib
Smallpox Monkeypox Vaccine
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.
Abemaciclib (Verzenio) is a cancer medicine that can weaken your immune system. The smallpox/monkeypox vaccine we're talking about here is a live vaccine, meaning it contains a weakened form of the virus. Normally your immune system easily controls it, but if your defenses are lowered by cancer treatment, that weakened virus could actually cause an infection instead of just protecting you.
Because of this, this live vaccine is generally not given while you're on this kind of therapy. The good news is your care team can plan around it. Please don't stop or start anything on your own. Just talk with your oncologist or pharmacist about the right timing for any vaccines.
Interaction: Abemaciclib (a CDK4/6 inhibitor) can cause immunosuppression, and administering a live replicating smallpox/monkeypox vaccine to an immunocompromised patient risks vaccine-strain infection or disseminated disease.
- Direction/mechanism: Diminished host immune response permits uncontrolled replication of the live vaccine virus (PD effect, not CYP-mediated).
- Severity: Contraindicated. Evidence: Established.
- Management: Avoid live vaccination during active therapy and in severe immunodeficiency. Patients with malignancy in remission, restored immunocompetence, and chemotherapy discontinued at least 3 months may be candidates. Coordinate timing with oncology.
What happens
An increased risk of infection by the live vaccine
Interaction Deep Dive
Smallpox and monkeypox vaccine should not be given to people who have severe immunodeficiency 2. A live vaccine may be given to patients with leukemia, lymphoma, or other malignancies provided their disease is in remission, their immunocompetence has been restored, and at least 3 months have passed since chemotherapy was stopped 1.
Why it happens (mechanism)
Decreased immune response allows live vaccine to produce infection
How to manage this interaction
What your care team typically does:
- Avoids giving this live smallpox/monkeypox vaccine while your immune system is suppressed by cancer therapy.
- Considers vaccination only once your disease is in remission, your immune function has recovered, and chemotherapy has been stopped for at least 3 months.
- May look at non-live vaccine options or adjust timing where appropriate.
What you should do: Keep taking your abemaciclib as prescribed and do not stop it on your own. Before getting any vaccine, tell the provider you are on cancer treatment, and confirm timing with your oncologist or pharmacist.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abemaciclib and Smallpox Monkeypox Vaccine together?
Do not receive the live smallpox/monkeypox vaccine while on abemaciclib because your weakened immune system could let the vaccine virus cause an infection; discuss safe timing with your oncologist or pharmacist. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abemaciclib and Smallpox Monkeypox Vaccine interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Abemaciclib and Smallpox Monkeypox Vaccine interaction managed?
What your care team typically does: Avoids giving this live smallpox/monkeypox vaccine while your immune system is suppressed by cancer therapy. Considers vaccination only once your disease is in remission, your immune function has recovered, and chemotherapy has been stopped for at least 3 months. May look at non-live vaccine options or adjust timing where appropriate. What you should do: Keep ta… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
Questions for your pharmacist
- Does my dose of Abemaciclib or Smallpox Monkeypox Vaccine 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)
- Centers for Disease Control and Prevention (CDC): Vaccines & Immunizations: altered immunocompetence. Centers for Disease Control and Prevention (CDC). Atlanta, GA. 2024.
- Product Information: ACAM2000 percutaneous injection, smallpox and mpox (vaccinia) vaccine, live percutaneous injection. Emergent Product Development Gaithersburg Inc (per FDA), Gaithersburg, MD, 2024. DailyMed
Keep reading about Abemaciclib
Keep reading about Smallpox Monkeypox Vaccine
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