Ripretinib and Abametapir: 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 recordRipretinib
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 you rub it on your scalp, some gets into your body and can briefly slow down a liver enzyme called CYP3A4. This enzyme is one of the main ways your body clears ripretinib (Qinlock), a cancer medicine.
When that enzyme is blocked, ripretinib can build up higher than intended, which may raise the chance of side effects. This is based on how the drugs work rather than on reports from real patients, but the concern is taken seriously. The good news is your care team can manage this easily, usually by spacing out the treatments. Please talk with your pharmacist or doctor before using both.
Mechanism: Abametapir inhibits CYP3A4. Ripretinib is a CYP3A4 substrate, so co-use is expected to increase ripretinib exposure (AUC/Cmax), potentially amplifying its effects and adverse events.
- Direction: Increased ripretinib exposure (neither drug is a prodrug requiring activation).
- Onset: Rapid; enzyme inhibition can persist for roughly 2 weeks after a single abametapir application.
- Evidence: Theoretical, based on mechanism.
- Severity: Major.
Management: Avoid CYP3A4 substrates such as ripretinib within 2 weeks after abametapir application. If concurrent use cannot be avoided, avoid using abametapir. Consider alternative lice therapy and closer monitoring for ripretinib toxicity if exposure is unavoidable.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Do not administer CYP3A4 substrates during the 2 week period following application of abametapir. When avoiding these 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
Both medicines are important, so the goal is to use them safely, not to stop your treatment on your own.
- Tell your pharmacist and prescriber that you take ripretinib (Qinlock) before using abametapir lice lotion.
- The usual approach is to avoid using a CYP3A4 medicine like ripretinib for about 2 weeks after applying abametapir, since the effect can linger.
- If separating them is not possible, your team may choose a different lice treatment instead.
- Your care team may also watch you more closely for ripretinib side effects if both are needed.
Keep taking your prescribed medicines and raise any timing questions with your care team.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Ripretinib and Abametapir together?
Abametapir can slow the breakdown of ripretinib and raise its levels, so avoid taking ripretinib for about 2 weeks after using abametapir, and ask your care team to help you space them or pick a different lice treatment. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ripretinib and Abametapir 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 Ripretinib and Abametapir interaction managed?
Both medicines are important, so the goal is to use them safely, not to stop your treatment on your own. Tell your pharmacist and prescriber that you take ripretinib (Qinlock) before using abametapir lice lotion. The usual approach is to avoid using a CYP3A4 medicine like ripretinib for about 2 weeks after applying abametapir, since the effect can linger. If separating them is not possible, your t… 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 Ripretinib or Abametapir 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 Ripretinib
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