Abametapir and Cobicistat: 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 recordCobicistat
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 only put it on your scalp, a little can get into your body and briefly slow down a liver enzyme called CYP3A4. That enzyme is one of the main ways your body breaks down cobicistat (Tybost).
When that clean-up slows down, cobicistat can build up higher than usual, which may make side effects more likely. The good news is this is easy to plan around. Don't stop either medicine on your own, but let your pharmacist or doctor know you use both so they can space out the timing and keep you safe.
Mechanism: Abametapir inhibits CYP3A4. Cobicistat is a CYP3A4 substrate (as well as being a CYP3A inhibitor itself), so co-exposure is expected to increase cobicistat plasma exposure (AUC/Cmax).
Direction: Increased cobicistat exposure and potential for enhanced/prolonged effects. Onset rapid; evidence theoretical.
- Management: Avoid CYP3A4 substrates for 2 weeks following topical abametapir application. If concomitant use is unavoidable, avoid abametapir.
- Enzyme inhibition can persist beyond the single application, hence the 2-week window.
- If both are needed, the care team can individualize timing and monitor more closely.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Within a 2-week window following the application of abametapir, refrain from administering CYP3A4 substrates. Should avoiding those substrates not be practical, then abametapir itself should not be used1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
What your care team may do:
- Time your medicines apart. Guidance is to avoid CYP3A4 substrates like cobicistat for up to 2 weeks after applying abametapir.
- If treating lice while on cobicistat isn't practical to separate, they may choose a different lice treatment instead.
What you should do:
- Keep taking cobicistat as prescribed and don't stop on your own.
- Before using abametapir lice lotion, tell your pharmacist or prescriber you take cobicistat so they can plan the timing or pick an alternative.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Cobicistat together?
Abametapir can raise cobicistat levels by briefly blocking the CYP3A4 enzyme, so separate them (avoid cobicistat for up to 2 weeks after the lice lotion) or use a different lice treatment. Ask your pharmacist before combining them. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Cobicistat 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 Cobicistat interaction managed?
What your care team may do: Time your medicines apart. Guidance is to avoid CYP3A4 substrates like cobicistat for up to 2 weeks after applying abametapir. If treating lice while on cobicistat isn't practical to separate, they may choose a different lice treatment instead. What you should do: Keep taking cobicistat as prescribed and don't stop on your own. Before using abametapir lice lotion, tell… 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 Cobicistat 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 Cobicistat
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