Abametapir and Benzhydrocodone: 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 recordBenzhydrocodone
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.
Here's what's going on. Abametapir is a lotion used to treat head lice. Even though you rub it on your scalp, a little gets into your body and can temporarily slow down a liver enzyme (called CYP3A4) for up to two weeks. That same enzyme is needed to turn benzhydrocodone into its active pain-relieving form and then break it down.
Because the enzyme is slowed, the opioid can build up more than expected. That can mean stronger effects like heavy drowsiness, confusion, or slowed breathing. This is a theoretical concern, but it's taken seriously. The good news: your care team can plan the timing of these medicines so you stay safe. Please check with your pharmacist or doctor before using both.
Mechanism: Abametapir is a potent CYP3A4 inhibitor. Topical application produces systemic exposure sufficient to inhibit CYP3A4 for up to 2 weeks. Benzhydrocodone is metabolized via CYP3A4 (among other pathways) to hydrocodone and onward.
- Direction: Inhibition reduces clearance of the CYP3A4 substrate, increasing exposure (AUC/Cmax) and risk of opioid toxicity (sedation, respiratory depression).
- Onset: rapid; effect persists ~2 weeks.
- Evidence: theoretical.
- Management: Avoid CYP3A4 substrates within 2 weeks of abametapir application; if unavoidable, avoid abametapir. If co-use occurs, monitor closely for opioid overdose signs.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Within a 2 week window following the application of abametapir, the use of CYP3A4 substrates should be avoided. When avoiding these substrates is not practical, abametapir itself should not be used 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
What your care team may do:
- Separate these medicines in time. The labeling advises avoiding CYP3A4 substrates like benzhydrocodone within 2 weeks after using abametapir.
- If lice treatment can't wait, they may choose a different lice product, or hold the opioid, so the two don't overlap.
- If both must be used, they may monitor you more closely for excessive drowsiness or slowed breathing.
What you should do: Keep taking your medicines as prescribed and don't stop anything on your own. Tell your pharmacist or prescriber that you may need both, so they can plan the timing and dose safely for you.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Benzhydrocodone together?
Abametapir can slow the enzyme that clears benzhydrocodone for up to two weeks, letting the opioid build up. Avoid using them within two weeks of each other, and ask your pharmacist or doctor to plan the timing. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Benzhydrocodone 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 Benzhydrocodone interaction managed?
What your care team may do: Separate these medicines in time. The labeling advises avoiding CYP3A4 substrates like benzhydrocodone within 2 weeks after using abametapir. If lice treatment can't wait, they may choose a different lice product, or hold the opioid, so the two don't overlap. If both must be used, they may monitor you more closely for excessive drowsiness or slowed breathing. What you s… 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 Benzhydrocodone 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 Benzhydrocodone
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