Ranolazine and Phenobarbital Interaction
Drug interaction information between Ranolazine and Phenobarbital.
Ranolazine and Phenobarbital have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Ranolazine and Phenobarbital. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Phenobarbital triggers your liver to process ranolazine too quickly, meaning there won't be enough medicine in your blood.
FDA Label Information
CYP3A Inducers Do not use ranolazine with CYP3A inducers such as rifampin, rifabutin, rifapentine, phenobarbital, phenytoin, carbamazepine, and St.
Ranolazine Also Interacts With
- Ketoconazole major
- Carbamazepine major
- Clarithromycin major
- Rifampin major
- Phenytoin major
Phenobarbital Also Interacts With
- Nirmatrelvir/Ritonavir major
- Voriconazole major
- Canagliflozin moderate
- Cenobamate moderate
- Clarithromycin moderate
Frequently Asked Questions
What SPL severity band is on file for Ranolazine + Phenobarbital?
Compiled FDA labeling labels this pair major. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Phenobarbital has 59 labeled pairs on file vs Ranolazine's 31. In the major band specifically: Ranolazine has 12 (also Ketoconazole, Carbamazepine, Clarithromycin, Rifampin); Phenobarbital has 3 (also Nirmatrelvir/Ritonavir, Voriconazole).
What mechanism field is on file for Ranolazine and Phenobarbital?
Phenobarbital triggers your liver to process ranolazine too quickly, meaning there won't be enough medicine in your blood.
Ranolazine carries more major-labeled pairs than Phenobarbital
SPL source-record counts only. This page's band is major · classes on file: Ranolazine (Late Sodium Current Inhibitor (Antianginal)); Phenobarbital (Anticonvulsant (Barbiturate)).
Ranolazine has 12 major-labeled pairs vs Phenobarbital's 3.
12 major · 7 moderate · 12 minor · 31 total
- Other major peers for Ranolazine
- Ketoconazole
- Carbamazepine
- Clarithromycin
- Rifampin
3 major · 13 moderate · 43 minor · 59 total
- Other major peers for Phenobarbital
- Nirmatrelvir/Ritonavir
- Voriconazole
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.