Abametapir and Dihydroergotamine: 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 recordDihydroergotamine
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 rub it on your scalp, some of it can get into your body and briefly block a liver enzyme (called CYP3A4) that breaks down many medicines. Dihydroergotamine is a migraine medicine that your body clears using that same enzyme.
If the enzyme is slowed down, dihydroergotamine can build up higher than expected. That matters because too much of this migraine drug can cause serious problems like severe narrowing of blood vessels, with cold hands or feet, numbness, or chest pain. The good news is your care team can manage this easily, usually by spacing out these two treatments. Please talk with your pharmacist or doctor before using both.
Mechanism: Abametapir is a CYP3A4 inhibitor; topical application produces systemic exposure sufficient to reduce clearance of CYP3A4 substrates. Dihydroergotamine is a CYP3A4 substrate (active drug, not a prodrug), so inhibition increases its exposure (AUC/Cmax) and pharmacologic effect.
- Direction: increased dihydroergotamine exposure, heightened risk of ergotism/vasospasm.
- Onset: rapid; enzyme inhibition can persist.
- Evidence: theoretical, but severity rated major given ergot toxicity potential.
- Management: Avoid CYP3A4 substrates for 2 weeks after abametapir application. If unavoidable, avoid abametapir. Monitor for peripheral ischemia and vasoconstrictive symptoms.
What happens
Increased exposure of CYP3A4 substrate
Interaction Deep Dive
Within a two-week window following the application of abametapir, the concurrent use of CYP3A4 substrates should be avoided. Should avoiding such substrates not be practical, then abametapir itself should not be used 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
The main strategy here is timing and avoidance. Both medicines are effective, but they should not overlap while abametapir is affecting your liver enzymes.
- Your care team will typically avoid dihydroergotamine for about 2 weeks after abametapir is applied to the scalp.
- If you truly need your migraine medicine during that window, the team may choose not to use abametapir and pick another lice treatment instead.
- Keep taking medicines exactly as prescribed, and tell your pharmacist or doctor that you use both so they can plan the timing.
Watch for and report cold or numb hands/feet, tingling, or chest pain.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Dihydroergotamine together?
Abametapir can raise dihydroergotamine levels and increase the risk of dangerous side effects, so avoid dihydroergotamine for about 2 weeks after using abametapir; if that is not possible, your team may skip the abametapir. Check with your pharmacist or doctor before using both. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Dihydroergotamine 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 Dihydroergotamine interaction managed?
The main strategy here is timing and avoidance. Both medicines are effective, but they should not overlap while abametapir is affecting your liver enzymes. Your care team will typically avoid dihydroergotamine for about 2 weeks after abametapir is applied to the scalp. If you truly need your migraine medicine during that window, the team may choose not to use abametapir and pick another lice treat… 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 Dihydroergotamine 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 Dihydroergotamine
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