Trimethoprim and Prenatal Multivitamin Interaction
Drug interaction information between Trimethoprim and Prenatal Multivitamin.
Trimethoprim and Prenatal Multivitamin have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Trimethoprim and Prenatal Multivitamin. 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
Trimethoprim can lower the amount of folate, an important B-vitamin, in your blood. This can make the folate in your prenatal vitamin less effective.
FDA Label Information
• L-dopa, triamterene, colchicine, and trimethoprim may decrease plasma folate levels. Caution should be exercised with the concomitant use of folinic acid and trimethoprim- sulfamethoxazole for the acute treatment of Pneumocystis carinii pneumonia in patients with HIV infection as it is associated with increased rates of treatment failure and mortality in a placebo-controlled study.
Trimethoprim Also Interacts With
- Theophylline major
- Spironolactone moderate
- Spironolactone (Acne) moderate
- Metformin minor
- Glipizide minor
Prenatal Multivitamin Also Interacts With
- Phenytoin moderate
- Metformin minor
- Fluoxetine minor
- Ibuprofen minor
- Potassium Chloride minor
Frequently Asked Questions
What SPL severity band is on file for Trimethoprim + Prenatal Multivitamin?
Compiled FDA labeling labels this pair moderate. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Prenatal Multivitamin has 23 labeled pairs on file vs Trimethoprim's 22. In the moderate band specifically: Trimethoprim has 3 (also Spironolactone, Spironolactone); Prenatal Multivitamin has 2 (also Phenytoin).
What mechanism field is on file for Trimethoprim and Prenatal Multivitamin?
Trimethoprim can lower the amount of folate, an important B-vitamin, in your blood. This can make the folate in your prenatal vitamin less effective.
Trimethoprim carries more major-labeled pairs than Prenatal Multivitamin
SPL source-record counts only. This page's band is moderate · classes on file: Trimethoprim (Dihydrofolate Reductase Inhibitor); Prenatal Multivitamin (Prenatal Vitamin).
Trimethoprim has 1 major-labeled pair vs Prenatal Multivitamin's 0. This page itself is in the moderate band, not the major band.
1 major · 3 moderate · 18 minor · 22 total
- Other moderate peers for Trimethoprim
- Spironolactone
- Spironolactone
0 major · 2 moderate · 21 minor · 23 total
- Other moderate peers for Prenatal Multivitamin
- Phenytoin
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.