Diazepam 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 recordDiazepam
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 on the scalp to treat head lice. Even though you put it on your skin, a little can get into your body and briefly slow down a liver enzyme called CYP3A4. That enzyme is one of the main ways your body breaks down diazepam (Valium).
If the enzyme is slowed, diazepam can build up more than usual. That could make you feel extra drowsy, dizzy, or unsteady. The good news is this effect is short-lived and easy to plan around. Please talk with your pharmacist or doctor about the timing of these two medicines so they can keep you safe.
Mechanism: Abametapir inhibits CYP3A4. Diazepam is partly metabolized by CYP3A4 (and CYP2C19), so co-exposure is predicted to increase diazepam AUC/Cmax, potentiating sedation, psychomotor impairment, and respiratory depression risk.
- Direction: increased diazepam exposure (inhibition; neither drug is a prodrug here)
- Onset: rapid
- Evidence: theoretical
- Severity: major
Management: Avoid CYP3A4 substrates, including diazepam, for 2 weeks after a single abametapir application. If concurrent use is unavoidable, avoid abametapir. If exposure occurs, monitor for excess sedation and CNS/respiratory depression.
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. Should avoiding these substrates not be practical, then abametapir itself should not be used1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism by abametapir
How to manage this interaction
Both medicines can usually be handled safely with a little planning by your care team. Because abametapir can raise diazepam levels for a short time, the guidance on file is about timing and avoidance, not permanent changes.
- Keep taking your medicines as prescribed and do not stop either one on your own.
- Tell your pharmacist or doctor before using abametapir if you take diazepam. The recommendation is to avoid CYP3A4 substrates for 2 weeks after applying abametapir, and if that is not possible, to avoid abametapir instead.
- Watch for extra drowsiness, dizziness, or feeling unsteady, and report these promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Diazepam and Abametapir together?
Abametapir can raise diazepam levels for about 2 weeks after use, which may increase drowsiness. Ask your pharmacist or doctor to space these apart or choose another option before using abametapir. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Diazepam 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 Diazepam and Abametapir interaction managed?
Both medicines can usually be handled safely with a little planning by your care team. Because abametapir can raise diazepam levels for a short time, the guidance on file is about timing and avoidance, not permanent changes. Keep taking your medicines as prescribed and do not stop either one on your own. Tell your pharmacist or doctor before using abametapir if you take diazepam. The recommendatio… 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 Diazepam 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 Diazepam
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