Ganaxolone and Mefenamic Acid: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ganaxolone
Mefenamic Acid
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
Increased ganaxolone exposure and an increased risk of ganaxolone-related adverse reactions
Interaction Deep Dive
Concomitant use of ganaxolone with mefenamic acid (UGT1A9 inhibitor) may increase ganaxolone exposure, which may increase the risk of ganaxolone associated adverse reactions in patients who have titrated to a stable ganaxolone dosage. Consider a reduction of ganaxolone maintenance dosage when initiating a UGT inhibitor1.
Why it happens (mechanism)
Inhibition of UGT1A9-mediated efflux transport of mefenamic acid
Common questions
Can I take Ganaxolone and Mefenamic Acid together?
Increased ganaxolone exposure and an increased risk of ganaxolone-related adverse reactions Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ganaxolone and Mefenamic Acid 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 Ganaxolone or Mefenamic Acid 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: ZTALMY® oral suspension, ganaxolone oral suspension. Marinus Pharmaceuticals Inc (per FDA), Radnor, PA, 2025. DailyMed
Keep reading about Ganaxolone
Keep reading about Mefenamic Acid
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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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