Memantine and Trimethoprim Interaction
Drug interaction information between Memantine and Trimethoprim.
Memantine and Trimethoprim have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Memantine and Trimethoprim. 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
Both drugs use the same pathway in the kidneys to leave the body. This can cause memantine to build up in the blood because the kidneys are busy processing the trimethoprim.
FDA Label Information
Cases of interactions with other OCT2 substrates, memantine and metformin, have also been reported.
Trimethoprim Also Interacts With
- Theophylline major
- Prenatal Multivitamin moderate
- Spironolactone moderate
- Spironolactone (Acne) moderate
- Metformin minor
Frequently Asked Questions
What SPL severity band is on file for Memantine + Trimethoprim?
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?
Trimethoprim has 22 labeled pairs on file vs Memantine's 2. In the minor band specifically: Memantine has 1; Trimethoprim has 18 (also Metformin, Glipizide, Warfarin, Methotrexate).
What mechanism field is on file for Memantine and Trimethoprim?
Both drugs use the same pathway in the kidneys to leave the body. This can cause memantine to build up in the blood because the kidneys are busy processing the trimethoprim.
Trimethoprim carries more major-labeled pairs than Memantine
SPL source-record counts only. This page's band is minor · classes on file: Memantine (NMDA Receptor Antagonist); Trimethoprim (Dihydrofolate Reductase Inhibitor).
Trimethoprim has 1 major-labeled pair vs Memantine's 0. This page itself is in the minor band, not the major band.
0 major · 1 moderate · 1 minor · 2 total
Memantine has no other minor-band peer in this dataset besides Trimethoprim.
1 major · 3 moderate · 18 minor · 22 total
- Other minor peers for Trimethoprim
- Metformin
- Glipizide
- Warfarin
- Methotrexate
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.