Maraviroc and Primidone: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Primidone
Maraviroc
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
Decreased levels of maraviroc
Interaction Deep Dive
The concomitant use of maraviroc (a CYP3A substrate) with phenobarbital (a CYP3A inducer) is contraindicated in adult and pediatric patients with CrCl less than 30 mL/min and in those with ESRD on regular hemodialysis. In adults with CrCl 30 mL/min or greater treated with maraviroc and phenobarbital (and no strong CYP3A inhibitors), increase the maraviroc dose to 600 mg orally twice daily. In pediatric patients with CrCl 30 mL/min or greater, concomitant use of maraviroc and phenobarbital is not recommended1.
Why it happens (mechanism)
Induction of CYP3A-mediated metabolism of maraviroc
Common questions
Can I take Maraviroc and Primidone together?
Decreased levels of maraviroc Always confirm with your pharmacist or prescriber before making any change.
How serious is the Maraviroc and Primidone interaction?
It is rated contraindicated. These should generally not be used together.
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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Maraviroc or Primidone 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: SELZENTRY(R) oral tablets, oral solution, maraviroc oral tablets, oral solution. Viiv Healthcare (per FDA), Research Triangle Park, NC, 2018. DailyMed
Keep reading about Primidone
Keep reading about Maraviroc
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