Lamotrigine and Carbamazepine Interaction
Drug interaction information between Lamotrigine and Carbamazepine.
Lamotrigine and Carbamazepine have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Lamotrigine and Carbamazepine. 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
Carbamazepine makes your body break down lamotrigine faster, which lowers the amount of medicine in your system by about 40%.
FDA Label Information
Carbamazepine and carbamazepine epoxide ↓ lamotrigine ? carbamazepine epoxide Addition of carbamazepine decreases lamotrigine concentration approximately 40%. May increase carbamazepine epoxide levels.
Lamotrigine Also Interacts With
- Dofetilide moderate
- Desmopressin moderate
- Valproate minor
- Rifampin minor
- Phenytoin minor
Carbamazepine Also Interacts With
- Nirmatrelvir/Ritonavir major
- Ranolazine major
- Risperidone major
- Lithium moderate
- Apixaban moderate
Frequently Asked Questions
What SPL severity band is on file for Lamotrigine + Carbamazepine?
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?
Carbamazepine has 129 labeled pairs on file vs Lamotrigine's 24. In the minor band specifically: Lamotrigine has 22 (also Valproate, Rifampin, Phenytoin, Phenobarbital); Carbamazepine has 110 (also Omeprazole, Ibuprofen, Citalopram, Amitriptyline).
What mechanism field is on file for Lamotrigine and Carbamazepine?
Carbamazepine makes your body break down lamotrigine faster, which lowers the amount of medicine in your system by about 40%.
Carbamazepine carries more major-labeled pairs than Lamotrigine
SPL source-record counts only. This page's band is minor · classes on file: Lamotrigine (Anticonvulsant); Carbamazepine (Anticonvulsant).
Carbamazepine has 3 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
- Rifampin
- Phenytoin
- Phenobarbital
3 major · 16 moderate · 110 minor · 129 total
- Other minor peers for Carbamazepine
- Omeprazole
- Ibuprofen
- Citalopram
- Amitriptyline
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.