Nevirapine and Ethosuximide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nevirapine
Ethosuximide
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.
What happens
Reduced ethosuximide exposure and reduced nevirapine exposure
Interaction Deep Dive
Use caution with concomitant use of ethosuximide (a CYP3A substrate) and nevirapine (a CYP3A inducer) may result in reduced exposure of both ethosuximide and nevirapine. Monitor virologic response and ethosuximide levels12.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of ethosuximide; altered nevirapine metabolism
Common questions
Can I take Nevirapine and Ethosuximide together?
Reduced ethosuximide exposure and reduced nevirapine exposure Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nevirapine and Ethosuximide interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
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 Nevirapine or Ethosuximide 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 (2)
- Product Information: VIRAMUNE(R) oral suspension, nevirapine oral suspension. Boehringer Ingelheim Pharmaceuticals Inc (per FDA), Ridgefield, CT, 2024. DailyMed
- Product Information: VIRAMUNE XR(R) oral extended-release tablets, nevirapine oral extended-release tablets. Boehringer Ingelheim Pharmaceuticals Inc (per FDA), Ridgefield, CT, 2024. DailyMed
Keep reading about Nevirapine
Keep reading about Ethosuximide
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