Abametapir and Melatonin: 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 recordMelatonin
No brand names on record
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 can get into your body and slow down a liver enzyme called CYP1A2. That enzyme is one of the main ways your body breaks down melatonin, the sleep aid.
With that enzyme slowed, melatonin can build up higher than usual, which may leave you feeling extra drowsy or groggy. The good news is this is easy to plan around. Talk with your pharmacist or doctor about spacing these out, since the effect can last for about two weeks after you use the lice treatment.
Mechanism: Abametapir inhibits CYP1A2, reducing metabolism of CYP1A2 substrates. Melatonin is a CYP1A2 substrate (not a prodrug), so inhibition increases melatonin exposure (higher AUC/Cmax) and may enhance sedative effects.
- Direction: increased melatonin effect
- Severity: major (per file)
- Evidence: theoretical
- Onset: unspecified; inhibition can persist up to ~2 weeks post-application
Management: Avoid CYP1A2 substrates, including melatonin, for 2 weeks after abametapir application. If concurrent use is unavoidable, avoid abametapir. Monitor for excess sedation if used together.
What happens
Increased exposure of CYP1A2 substrates
Interaction Deep Dive
Do not administer CYP1A2 substrates during the 2 weeks that follow abametapir application. Should this approach not be practical, refrain from using abametapir instead 1.
Why it happens (mechanism)
Inhibition of CYP1A2-mediated metabolism by abametapir
How to manage this interaction
Your care team can manage this easily with timing.
- Keep taking your medications as prescribed unless your pharmacist or doctor tells you otherwise.
- Because abametapir can slow melatonin's breakdown for up to 2 weeks after you apply it, the usual guidance is to avoid melatonin during that window.
- If avoiding melatonin during those two weeks is not feasible, the alternative is to avoid the abametapir treatment, so ask your provider which fits your situation.
- Watch for extra drowsiness or grogginess and report it to your pharmacist or prescriber.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Melatonin together?
Abametapir can raise melatonin levels for about two weeks after you use it, so avoid melatonin during that window unless your pharmacist or doctor advises otherwise, and watch for extra drowsiness. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Melatonin 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 Melatonin interaction managed?
Your care team can manage this easily with timing. Keep taking your medications as prescribed unless your pharmacist or doctor tells you otherwise. Because abametapir can slow melatonin's breakdown for up to 2 weeks after you apply it, the usual guidance is to avoid melatonin during that window. If avoiding melatonin during those two weeks is not feasible, the alternative is to avoid the abametapi… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Abametapir or Melatonin 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 Melatonin
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