Abametapir and Ivosidenib: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jun 30, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Abametapir
No brand names on recordIvosidenib
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.
Abametapir is a lotion used to treat head lice. Even though it is applied to the scalp, some of it can get into your body and briefly block a liver enzyme called CYP3A4. That same enzyme helps clear your cancer medicine, ivosidenib (Tibsovo). When the enzyme is blocked, ivosidenib can build up in your body, which may raise the chance of side effects, including heart rhythm changes.
The good news is this is very manageable. This effect is expected to last for about two weeks after using the lice lotion. Please talk with your pharmacist or doctor before using both, so your care team can plan the safest timing for you.
Mechanism: Abametapir inhibits CYP3A4. Ivosidenib is a CYP3A4 substrate, so co-exposure is predicted to increase ivosidenib AUC/Cmax.
- Direction: increased ivosidenib exposure and enhanced effect/toxicity risk (including QT prolongation).
- Onset: rapid; inhibition may persist roughly 2 weeks after a single topical application.
- Evidence: theoretical.
- Severity: major.
Management: Avoid administering CYP3A4 substrates such as ivosidenib within 2 weeks after abametapir application. If concomitant use is unavoidable, avoid abametapir. If exposure occurs, consider closer clinical and ECG monitoring; any dose changes should be individualized by the care team.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Do not administer CYP3A4 substrates during the 2 weeks following the application of abametapir. When avoiding such substrates is not possible, refrain from using abametapir instead1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
Keep taking your ivosidenib (Tibsovo) as prescribed. The concern is the head lice lotion abametapir, not stopping your cancer treatment.
- The recommended approach is to avoid using CYP3A4-affected medicines like ivosidenib within 2 weeks after applying abametapir. If that timing is not possible, the guidance is to avoid the abametapir instead.
- Before using any lice treatment, tell your pharmacist or oncology team you take ivosidenib so they can pick a safe option or timing.
- Your team may monitor you more closely (including heart rhythm) if both are needed, and any dosing can be individualized by them.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Ivosidenib together?
Abametapir can raise ivosidenib levels by blocking CYP3A4 for about two weeks, so avoid using ivosidenib within 2 weeks of the lice lotion; if that is not possible, avoid the lotion. Check with your oncology team or pharmacist before combining them. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Ivosidenib interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How is the Abametapir and Ivosidenib interaction managed?
Keep taking your ivosidenib (Tibsovo) as prescribed. The concern is the head lice lotion abametapir, not stopping your cancer treatment. The recommended approach is to avoid using CYP3A4-affected medicines like ivosidenib within 2 weeks after applying abametapir. If that timing is not possible, the guidance is to avoid the abametapir instead. Before using any lice treatment, tell your pharmacist o… Management is individual — always follow your own care team's guidance.
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 Abametapir or Ivosidenib 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: XEGLYZE(TM) topical lotion, abametapir topical lotion. Dr Reddy’s Laboratories Inc (per FDA), Princeton, NJ, 2020. DailyMed
Keep reading about Abametapir
Keep reading about Ivosidenib
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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