Diflunisal and Mefenamic Acid Interaction
Drug interaction information between Diflunisal and Mefenamic Acid.
Diflunisal and Mefenamic Acid have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Diflunisal and Mefenamic Acid. 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
Taking these two drugs together increases the risk of stomach bleeding and ulcers without providing extra relief. Both drugs are similar and can irritate the lining of your digestive system.
FDA Label Information
NSAIDs and Salicylates Clinical Impact: Concomitant use of mefenamic acid with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy (see Warnings ; Gastrointestinal Bleeding, Ulceration and Perforation ).
Diflunisal Also Interacts With
- Methotrexate moderate
- Cyclosporine moderate
- Celecoxib moderate
- Indomethacin moderate
- Meloxicam moderate
Mefenamic Acid Also Interacts With
- Methotrexate moderate
- Warfarin moderate
- Meloxicam minor
- Furosemide minor
- Aspirin minor
Frequently Asked Questions
What SPL severity band is on file for Diflunisal + Mefenamic Acid?
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?
Diflunisal has 17 labeled pairs on file vs Mefenamic Acid's 15. In the moderate band specifically: Diflunisal has 11 (also Methotrexate, Cyclosporine, Celecoxib, Indomethacin); Mefenamic Acid has 3 (also Methotrexate, Warfarin).
What mechanism field is on file for Diflunisal and Mefenamic Acid?
Taking these two drugs together increases the risk of stomach bleeding and ulcers without providing extra relief. Both drugs are similar and can irritate the lining of your digestive system.
Diflunisal's labeled portfolio outnumbers Mefenamic Acid
SPL source-record counts only. This page's band is moderate · classes on file: Diflunisal (Nonsteroidal Anti-Inflammatory Drug (NSAID)); Mefenamic Acid (Nonsteroidal Anti-Inflammatory Drug (NSAID)).
0 major · 11 moderate · 6 minor · 17 total
- Other moderate peers for Diflunisal
- Methotrexate
- Cyclosporine
- Celecoxib
- Indomethacin
0 major · 3 moderate · 12 minor · 15 total
- Other moderate peers for Mefenamic Acid
- Methotrexate
- Warfarin
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.