Lamotrigine and Rifampin Interaction
Drug interaction information between Lamotrigine and Rifampin.
Lamotrigine and Rifampin have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Lamotrigine and Rifampin. 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
Rifampin causes your body to clear lamotrigine out of your system much faster than normal, lowering the drug levels in your blood.
FDA Label Information
Rifampin ↓ lamotrigine Decreased lamotrigine AUC approximately 40%. ( 7 , 12.3 ) Carbamazepine, phenytoin, phenobarbital, primidone, and rifampin decrease lamotrigine concentrations by approximately 40%.
Lamotrigine Also Interacts With
- Dofetilide moderate
- Desmopressin moderate
- Valproate minor
- Carbamazepine minor
- Phenytoin minor
Rifampin Also Interacts With
- Darunavir major
- Bictegravir/Emtricitabine/Tenofovir major
- Glecaprevir/Pibrentasvir major
- Nirmatrelvir/Ritonavir major
- Pitavastatin major
Frequently Asked Questions
What SPL severity band is on file for Lamotrigine + Rifampin?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Rifampin has 137 labeled pairs on file vs Lamotrigine's 24. In the minor band specifically: Lamotrigine has 22 (also Valproate, Carbamazepine, Phenytoin, Phenobarbital); Rifampin has 103 (also Metoprolol, Losartan, Simvastatin, Glipizide).
What mechanism field is on file for Lamotrigine and Rifampin?
Rifampin causes your body to clear lamotrigine out of your system much faster than normal, lowering the drug levels in your blood.
Rifampin carries more major-labeled pairs than Lamotrigine
SPL source-record counts only. This page's band is minor · classes on file: Lamotrigine (Anticonvulsant); Rifampin (Rifamycin Antibiotic).
Rifampin has 8 major-labeled pairs vs Lamotrigine's 0. This page itself is in the minor band, not the major band.
0 major · 2 moderate · 22 minor · 24 total
- Other minor peers for Lamotrigine
- Valproate
- Carbamazepine
- Phenytoin
- Phenobarbital
8 major · 26 moderate · 103 minor · 137 total
- Other minor peers for Rifampin
- Metoprolol
- Losartan
- Simvastatin
- Glipizide
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.