Abametapir and Elbasvir: 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 recordElbasvir
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 on the scalp to treat head lice. Even though it goes on your hair, 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 elbasvir (a hepatitis C medicine).
When that enzyme is slowed, elbasvir can build up higher than usual, which could mean more side effects. This is expected based on how the drugs work rather than proven in studies, but it is treated seriously. The good news: this effect fades over about two weeks, and your care team can plan the timing so you stay safe.
Mechanism: Abametapir is a CYP3A4 inhibitor; elbasvir is a CYP3A4 substrate. Inhibition reduces elbasvir metabolism, increasing its exposure (AUC/Cmax) and the potential for concentration-related adverse effects.
- Direction: increased elbasvir exposure (neither drug is a prodrug requiring activation).
- Onset: rapid.
- Magnitude: not quantified.
- Evidence: theoretical.
- Severity: major.
Management: Avoid CYP3A4 substrates, including elbasvir, for 2 weeks following a single application of abametapir. If concurrent use of the substrate cannot be avoided, avoid abametapir. Coordinate timing with the prescriber.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
For a period of 2 weeks following abametapir application, refrain from administering CYP3A4 substrates. When such avoidance cannot be achieved, abametapir itself should not be used 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 timing rather than stopping your hepatitis C treatment.
- Keep taking your elbasvir as prescribed unless your care team tells you otherwise.
- The advice on file is to avoid CYP3A4 substrates (like elbasvir) for about 2 weeks after applying abametapir lice lotion, since the effect lingers even after one use.
- If avoiding that overlap is not possible, the alternative is to avoid using the abametapir lotion and treat lice another way.
- Tell your pharmacist or prescriber before using any lice treatment so the timing can be planned and you can be watched more closely if needed.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Elbasvir together?
Abametapir can raise elbasvir levels by slowing its breakdown, so avoid elbasvir for about two weeks after using the lice lotion; if you cannot, skip the lotion. Check with your pharmacist or prescriber before using either. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Elbasvir 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 Elbasvir interaction managed?
Both of these can usually be handled with good timing rather than stopping your hepatitis C treatment. Keep taking your elbasvir as prescribed unless your care team tells you otherwise. The advice on file is to avoid CYP3A4 substrates (like elbasvir) for about 2 weeks after applying abametapir lice lotion, since the effect lingers even after one use. If avoiding that overlap is not possible, the a… 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 Elbasvir 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 Elbasvir
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