Codeine 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 recordCodeine
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 it's applied to the scalp, some of it gets into your body and can briefly slow down a liver enzyme (called CYP3A4) that helps break down many medicines.
Codeine is partly handled by that same enzyme. With the enzyme slowed, more codeine and its byproducts can build up in your body, which may mean stronger effects like extra drowsiness, dizziness, or slowed breathing. This is a theoretical concern based on how the drugs work, not on reported cases. Good news: your pharmacist or doctor can easily manage this by spacing things out or choosing another option, so please check with them before combining these two.
Mechanism: Abametapir inhibits CYP3A4, reducing metabolism of CYP3A4 substrates and increasing their systemic exposure (AUC/Cmax). Codeine is partially metabolized via CYP3A4 (to norcodeine), so accumulation of codeine and its metabolites is plausible.
- Direction: Increased codeine exposure and opioid effect (sedation, respiratory depression).
- Onset: Rapid; inhibition may persist and the effect is expected for roughly 2 weeks post-application.
- Evidence: Theoretical.
- Severity: Major.
Management: Avoid CYP3A4 substrates within 2 weeks after abametapir application; if unavoidable, avoid abametapir. If co-exposure occurs, monitor for enhanced opioid effects.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
For a period of 2 weeks following the application of abametapir, do not use CYP3A4 substrates. When avoiding these substrates is not possible, then abametapir itself should not be used 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
How your care team handles this:
- The main strategy is timing and avoidance. Guidance is to avoid CYP3A4 substrates like codeine for about 2 weeks after applying abametapir. If that isn't feasible, the abametapir treatment itself may be avoided instead.
- Your team may also watch you more closely for increased opioid effects such as drowsiness or slowed breathing if both are used near the same time.
What you should do: Don't stop or change either medicine on your own. Tell your pharmacist or prescriber that you use codeine before starting abametapir so they can help you plan the timing or pick an alternative.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Codeine and Abametapir together?
Abametapir can raise codeine levels by briefly blocking the enzyme that clears it, so avoid combining them within about 2 weeks of applying abametapir. Talk to your pharmacist or doctor to plan the timing or choose an alternative. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Codeine 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 Codeine and Abametapir interaction managed?
How your care team handles this: The main strategy is timing and avoidance. Guidance is to avoid CYP3A4 substrates like codeine for about 2 weeks after applying abametapir. If that isn't feasible, the abametapir treatment itself may be avoided instead. Your team may also watch you more closely for increased opioid effects such as drowsiness or slowed breathing if both are used near the same time.… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Codeine 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 Codeine
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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