Abametapir and Verapamil: 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 recordVerapamil
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 it goes on your scalp, a little gets into your body and can slow down an enzyme called CYP3A4 that helps clear other medicines. Verapamil (Calan, Isoptin, Verelan) is a blood pressure and heart-rhythm medicine that this enzyme breaks down.
If the enzyme is slowed, verapamil can build up in your body, which could lead to lower blood pressure, a slower heart rate, dizziness, or constipation. This is based on how the drugs work, not on reports of it happening. The good news is your care team can manage this easily by planning the timing, so just check with your pharmacist or doctor before using both.
Effect: Increased exposure (AUC/Cmax) of the CYP3A4 substrate verapamil.
Mechanism: Abametapir inhibits CYP3A4-mediated metabolism. Verapamil is a CYP3A4 substrate (and itself a CYP3A4 inhibitor), so reduced clearance may elevate plasma levels.
- Direction: Increased verapamil effect (hypotension, bradycardia, AV block, constipation).
- Onset: Rapid; enzyme inhibition can persist ~2 weeks post-application.
- Evidence: Theoretical.
- Management: Avoid CYP3A4 substrates for 2 weeks after a single abametapir application; if unavoidable, avoid abametapir. Consider closer cardiovascular monitoring if co-exposure occurs.
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. Should that not be possible, then abametapir itself should be avoided 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
Both medicines are usually fine on their own; the concern is using them close together. Here is what a care team typically does:
- Timing: Abametapir's effect on the enzyme can last about 2 weeks after a single scalp application, so the general guidance is to avoid CYP3A4 substrates like verapamil during that window.
- If separating them is not possible, the team may reconsider whether abametapir should be used at all.
- If both are used together, your team may monitor you more closely for low blood pressure, slow heart rate, or dizziness.
What to do: Keep taking your verapamil as prescribed and tell your pharmacist or prescriber before using abametapir so they can plan the timing.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Abametapir and Verapamil together?
Abametapir can raise verapamil levels for about two weeks after use, so avoid pairing them in that window unless your care team plans it and watches for low blood pressure or slow heart rate. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abametapir and Verapamil 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 Verapamil interaction managed?
Both medicines are usually fine on their own; the concern is using them close together. Here is what a care team typically does: Timing: Abametapir's effect on the enzyme can last about 2 weeks after a single scalp application, so the general guidance is to avoid CYP3A4 substrates like verapamil during that window. If separating them is not possible, the team may reconsider whether abametapir shou… 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 Abametapir or Verapamil 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 Verapamil
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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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