Abametapir and Riluzole: 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 recordRiluzole
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 goes on your scalp, a little gets into your body and can briefly slow down a liver enzyme called CYP1A2. Your other medicine, riluzole (Rilutek, Tiglutik, Exservan), is cleared from your body by that same enzyme.
If the enzyme is slowed, riluzole can build up higher than usual, which could raise the chance of side effects like dizziness, tiredness, or nausea. This concern is based on how the drugs work rather than reported cases, but the makers advise keeping them apart. The good news: your care team can easily manage this by spacing out the timing. Just check with your pharmacist or doctor before using the lice lotion.
Interaction: Abametapir is a CYP1A2 inhibitor; riluzole is a CYP1A2 substrate. Coadministration is predicted to increase riluzole exposure (AUC/Cmax) via reduced CYP1A2-mediated metabolism.
- Direction: Increased riluzole levels, greater risk of dose-related adverse effects (hepatotoxicity, dizziness, GI upset, neutropenia).
- Evidence: Theoretical, based on abametapir's known enzyme inhibition.
- Onset: Unspecified; inhibition may persist for a period after topical application.
- Management: Avoid CYP1A2 substrates within 2 weeks after abametapir application. If unavoidable, avoid abametapir. Monitor for enhanced riluzole effects if co-exposure occurs.
What happens
Increased exposure of CYP1A2 substrates
Interaction Deep Dive
Do not administer CYP1A2 substrates during the 2-week period following abametapir application. When avoiding these substrates is not possible, then abametapir should not be used 1.
Why it happens (mechanism)
Inhibition of CYP1A2-mediated metabolism by abametapir
How to manage this interaction
Both medicines can be used safely with a little planning. The main strategy here is timing.
- Keep taking your riluzole exactly as prescribed. Do not stop it on your own.
- Before using the abametapir lice lotion, tell your pharmacist or doctor that you take riluzole.
- Guidance is to avoid CYP1A2 substrates like riluzole for about 2 weeks after applying abametapir. If that spacing is not possible, your team may recommend avoiding the abametapir lotion and using a different lice treatment.
- Ask your care team if you should watch more closely for side effects such as unusual tiredness, dizziness, or nausea.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Riluzole together?
Abametapir can raise riluzole levels by slowing its breakdown, so avoid riluzole for about two weeks after using the lice lotion, or choose a different lice treatment; check with your pharmacist or doctor first. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Riluzole interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Abametapir and Riluzole interaction managed?
Both medicines can be used safely with a little planning. The main strategy here is timing. Keep taking your riluzole exactly as prescribed. Do not stop it on your own. Before using the abametapir lice lotion, tell your pharmacist or doctor that you take riluzole. Guidance is to avoid CYP1A2 substrates like riluzole for about 2 weeks after applying abametapir. If that spacing is not possible, your… 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 Riluzole 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 Riluzole
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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.
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