Ranolazine and Phenobarbital

Desk tier: Avoid together

Mechanism: moderate CYP3A4 induction of clearance (↓ exposure / loss of efficacy)

“Do not use RANEXA with CYP3A inducers such as rifampin, rifabutin, rifapentine, phenobarbital, phenytoin, carbamazepine”

Ranexa (ranolazine), section 7.1 (see 4 CONTRAINDICATIONS). DailyMed label

Why this grade

Ranexa (ranolazine) label, Contraindications

The Ranexa (ranolazine) label lists this combination under Contraindications. Contraindications: "RANEXA is contraindicated in patients: … Taking inducers of CYP3A" 7.1 (see 4 CONTRAINDICATIONS): "Do not use RANEXA with CYP3A inducers such as rifampin, rifabutin, rifapentine, phenobarbital, phenytoin, carbamazepine" Retrieved from DailyMed 2026-09-27.

Open source

FDA interaction table

FDA's example-interaction table lists Phenobarbital as a moderate CYP3A inducer. FDA grades the roles; the severity tier on this row is the desk's rule. Table content current as of 2026-05-29.

Open source

CPIC / ClinPGx

Phenotype rows paraphrase published CPIC tables. Open the guideline. This desk is not a PGx report.

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Open this pair in the desk

All pairs for Ranolazine · Phenobarbital

Enzyme behind this pair: CYP3A4

Educational reference only. Not FDA-cleared. The Prescribing Information governs.

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