Abiraterone Acetate and Abametapir: 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 recordAbiraterone Acetate
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.
Here's what's going on. Abametapir is a lotion used to treat head lice. Even though you only put it on your scalp, it can briefly slow down a liver enzyme (called CYP3A4) that your body uses to break down many medicines. Abiraterone acetate (Yonsa, Zytiga), your prostate cancer medicine, is cleared by that same enzyme.
When that enzyme is slowed, your abiraterone can build up higher than intended, which could raise the chance of side effects. The good news is this is easy to plan around. Please don't stop either medicine on your own. Let your pharmacist or doctor know you use both so they can time them safely.
Mechanism: Abametapir inhibits CYP3A4. Abiraterone acetate is a CYP3A4 substrate (and is hydrolyzed to active abiraterone), so inhibition raises abiraterone exposure (increased AUC/Cmax), with potentially amplified pharmacodynamic and adverse effects.
- Direction: increased substrate exposure
- Onset: rapid
- Evidence: theoretical
- Magnitude: not quantified
Management: Per labeling, avoid CYP3A4 substrates for 2 weeks following topical abametapir application; if concomitant use is unavoidable, avoid abametapir. Coordinate timing between prescribers and monitor for abiraterone-related toxicity (hypertension, hypokalemia, hepatic effects, fluid retention) if overlap occurs.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
For a period of 2 weeks following abametapir application, refrain from administering CYP3A4 substrates. Where this cannot be done, do not use abametapir1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
This is manageable with a little planning by your care team.
- Keep taking your abiraterone as prescribed for your prostate cancer. Do not stop it on your own.
- The usual approach is to avoid CYP3A4 substrates like abiraterone for about 2 weeks after applying abametapir lice lotion. If that spacing isn't possible, the abametapir may be avoided instead.
- Tell your pharmacist or prescriber before using any lice treatment so they can decide on timing or an alternative.
- If you do use both close together, your team may watch you more closely for abiraterone side effects such as high blood pressure or swelling.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abiraterone Acetate and Abametapir together?
Abametapir can raise abiraterone levels by blocking the enzyme that clears it, so space them out by about 2 weeks (or skip the abametapir) and let your pharmacist or doctor coordinate the timing. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abiraterone Acetate and Abametapir 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 Abiraterone Acetate and Abametapir interaction managed?
This is manageable with a little planning by your care team. Keep taking your abiraterone as prescribed for your prostate cancer. Do not stop it on your own. The usual approach is to avoid CYP3A4 substrates like abiraterone for about 2 weeks after applying abametapir lice lotion. If that spacing isn't possible, the abametapir may be avoided instead. Tell your pharmacist or prescriber before using… 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 Abiraterone Acetate or Abametapir 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 Abiraterone Acetate
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