Abametapir and Voxelotor: 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 recordVoxelotor
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.
Let me explain this one simply. Abametapir is a lotion used on the scalp to treat head lice. Even though it goes on your skin, a little can get into your body and briefly slow down a liver enzyme called CYP3A4. That enzyme helps your body break down many medicines, including voxelotor (Oxbryta), which you take for sickle cell disease.
When that enzyme is slowed, voxelotor can build up higher than expected, which could mean more side effects. This concern is based on how the drugs work, not on real-world reports. The good news is that this is easy to plan around, so just talk with your pharmacist or doctor before using both.
Effect: Increased voxelotor exposure via CYP3A4 inhibition by abametapir.
- Direction: Abametapir inhibits CYP3A4-mediated metabolism; voxelotor is a CYP3A4 substrate, so its AUC/Cmax may rise. Neither is a prodrug here, so this raises voxelotor exposure and side-effect risk.
- Onset: Rapid.
- Evidence: Theoretical; based on mechanism, not clinical reports.
- Severity: Major (labeled).
- Management: Avoid CYP3A4 substrates, including voxelotor, for 2 weeks after a single topical abametapir application. If concurrent use is unavoidable, avoid abametapir. Consider clinical monitoring if co-exposure occurs.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Refrain from administering CYP3A4 substrates during the 2-week period following abametapir application. Should this be unavoidable, abametapir itself should not be used 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
Here is how a care team usually handles this:
- Timing: Abametapir's enzyme-slowing effect can last about 2 weeks after a single scalp application, so your team may space these apart rather than use them together.
- Alternative: If you need voxelotor, your team may choose a different lice treatment; if abametapir is needed, they may pause or adjust the other medicine.
- Monitoring: If both are used, your team may watch you more closely for side effects.
Keep taking your medicines as prescribed, and before using an abametapir lice lotion, tell your pharmacist or doctor you take voxelotor so they can plan the timing.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Voxelotor together?
Abametapir can raise voxelotor levels by briefly blocking the CYP3A4 enzyme, so avoid using them together for about 2 weeks after the lice treatment. Check with your pharmacist or doctor to time these safely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Voxelotor 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 Voxelotor interaction managed?
Here is how a care team usually handles this: Timing: Abametapir's enzyme-slowing effect can last about 2 weeks after a single scalp application, so your team may space these apart rather than use them together. Alternative: If you need voxelotor, your team may choose a different lice treatment; if abametapir is needed, they may pause or adjust the other medicine. Monitoring: If both are used, you… 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 Voxelotor 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 Voxelotor
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