Abametapir and Perampanel: 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 recordPerampanel
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 put it on your scalp, a little bit gets into your body and can briefly slow down a liver enzyme called CYP3A4. That same enzyme is what your body uses to break down perampanel (Fycompa), your seizure medicine.
When that enzyme is slowed, perampanel can build up higher than usual. That could mean more of its side effects, like drowsiness, dizziness, or trouble with balance. This is expected based on how the drugs work, not from real-world reports. The good news is your care team can plan the timing and watch you closely, so please check with your pharmacist or doctor before using both.
Interaction: Abametapir is a transient CYP3A4 inhibitor. Perampanel is a CYP3A4 substrate, so inhibition is expected to reduce its clearance and increase systemic exposure (AUC/Cmax).
- Direction: Increased perampanel exposure, greater risk of CNS effects (somnolence, dizziness, ataxia, irritability).
- Onset: Rapid.
- Evidence: Theoretical, based on mechanism.
- Magnitude: Not quantified.
Management: Avoid CYP3A4 substrates for 2 weeks after a single abametapir application; if unavoidable, avoid abametapir. If both are used, individualize perampanel dosing and monitor for enhanced CNS depression.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Do not administer CYP3A4 substrates during the 2 weeks following application of abametapir. Should avoiding such substrates not be practical, refrain from using abametapir instead 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
Both of these can usually be handled with good planning. Because abametapir can raise perampanel levels for a short time, the guidance is to separate them in time.
- Keep taking your perampanel (Fycompa) as prescribed. Do not stop or change it on your own.
- Before using abametapir lice lotion, tell your pharmacist or prescriber you take perampanel. The usual advice is to avoid CYP3A4 medicines like perampanel for about 2 weeks after applying abametapir, or to avoid the abametapir if that is not possible.
- If both are needed, your team may monitor you more closely and adjust as needed.
- Report new drowsiness, dizziness, or unsteadiness.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Perampanel together?
Abametapir can briefly raise perampanel levels and its side effects; the safest approach is to avoid perampanel for about 2 weeks after using abametapir, so talk with your pharmacist or doctor about timing. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Perampanel 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 Perampanel interaction managed?
Both of these can usually be handled with good planning. Because abametapir can raise perampanel levels for a short time, the guidance is to separate them in time. Keep taking your perampanel (Fycompa) as prescribed. Do not stop or change it on your own. Before using abametapir lice lotion, tell your pharmacist or prescriber you take perampanel. The usual advice is to avoid CYP3A4 medicines like p… 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 Perampanel 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 Perampanel
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