Abametapir and Dabrafenib: 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 recordDabrafenib
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, and even though you only put it on your scalp, a small amount can get into your body. Once there, it can block a liver enzyme called CYP3A4 for up to two weeks. Your cancer medicine dabrafenib (Tafinlar) is partly broken down by that same enzyme.
When the enzyme is blocked, more dabrafenib can build up in your body, which could mean stronger side effects. The good news is this is easy to plan around. This warning is based on how the drugs work rather than reports of harm, so please talk with your pharmacist or doctor before using both, and they can guide the timing.
Mechanism: Abametapir is a CYP3A4 inhibitor; topical application can produce systemic inhibition lasting up to ~2 weeks. Dabrafenib is a CYP3A4 substrate (not a prodrug), so inhibition is expected to raise dabrafenib exposure (AUC/Cmax), increasing risk of dose-related toxicity.
- Direction: increased dabrafenib exposure / effect
- Onset: rapid
- Evidence: theoretical (based on inhibitor labeling, no clinical outcome data)
- Management: Avoid CYP3A4 substrates, including dabrafenib, for 2 weeks after abametapir application. If concomitant use is unavoidable, avoid abametapir. Consider closer monitoring for dabrafenib-related toxicity if exposure occurs.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Do not administer CYP3A4 substrates during the 2 weeks following abametapir application. Should this be impractical, refrain from using abametapir1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
Both medicines can be used safely with a little planning by your care team.
- Keep taking your dabrafenib as prescribed and do not stop your cancer treatment on your own.
- Before using abametapir lice lotion, tell your pharmacist or doctor that you take dabrafenib.
- The usual approach is to avoid a CYP3A4 medicine like dabrafenib for about 2 weeks after applying abametapir. If that timing is not workable, your team may choose a different lice treatment instead.
- If both are used, your team may watch you more closely for dabrafenib side effects.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Dabrafenib together?
Abametapir can raise dabrafenib levels by blocking CYP3A4 for up to two weeks, so let your care team plan the timing or pick a different lice treatment. Do not stop your dabrafenib on your own. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Dabrafenib 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 Dabrafenib interaction managed?
Both medicines can be used safely with a little planning by your care team. Keep taking your dabrafenib as prescribed and do not stop your cancer treatment on your own. Before using abametapir lice lotion, tell your pharmacist or doctor that you take dabrafenib. The usual approach is to avoid a CYP3A4 medicine like dabrafenib for about 2 weeks after applying abametapir. If that timing is not worka… 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 Dabrafenib 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 Dabrafenib
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