Tacrolimus 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 recordTacrolimus
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 to treat head lice. Even though you put it on your scalp, some of it can get into your body and briefly block a liver enzyme called CYP3A4. That enzyme is one of the main ways your body breaks down tacrolimus, an important medicine that quiets your immune system after a transplant or for certain conditions.
If the enzyme is slowed down, tacrolimus can build up in your blood and cause stronger side effects, like kidney strain, tremors, or high blood pressure. Tacrolimus is a drug where even small changes matter, so this is worth a heads-up. The good news: your care team can manage this easily by planning the timing. Please talk with your doctor or pharmacist before using abametapir.
Interaction: Abametapir is a CYP3A4 inhibitor; tacrolimus is a narrow-therapeutic-index CYP3A4 substrate. Inhibition reduces tacrolimus metabolism, increasing exposure (AUC/Cmax) and risk of nephrotoxicity, neurotoxicity, hypertension, and hyperglycemia.
- Direction: increased tacrolimus effect/toxicity
- Onset: rapid
- Evidence: theoretical (mechanism-based)
- Severity: major
Management: Per labeling, avoid CYP3A4 substrates for 2 weeks after a single topical abametapir application; if concomitant use is unavoidable, avoid abametapir. If exposure occurs, monitor tacrolimus trough levels closely and individualize dosing.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
For a period of two weeks following the application of abametapir, refrain from using CYP3A4 substrates. Should this be impractical, abametapir itself should not be used 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
Keep taking your tacrolimus exactly as prescribed. The main step here is timing and coordination with your care team before any abametapir lice treatment.
- The official guidance is to avoid CYP3A4 substrates (including tacrolimus) for 2 weeks after applying abametapir. If that is not possible, the abametapir treatment is avoided instead.
- Tell your prescriber and pharmacist you take tacrolimus before using any lice product.
- If both are used, your team may check your tacrolimus blood levels more closely and adjust the dose to keep it in a safe range.
Do not start, stop, or change either medicine on your own.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Tacrolimus and Abametapir together?
Abametapir can briefly raise tacrolimus levels by blocking its breakdown, so avoid using it within 2 weeks of tacrolimus unless your care team says otherwise and monitors your levels. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tacrolimus 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 Tacrolimus and Abametapir interaction managed?
Keep taking your tacrolimus exactly as prescribed. The main step here is timing and coordination with your care team before any abametapir lice treatment. The official guidance is to avoid CYP3A4 substrates (including tacrolimus) for 2 weeks after applying abametapir. If that is not possible, the abametapir treatment is avoided instead. Tell your prescriber and pharmacist you take tacrolimus befor… 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 Tacrolimus 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 Tacrolimus
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist