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Oxaprozin and Diflunisal Interaction

Drug interaction information between Oxaprozin and Diflunisal.

Oxaprozin and Diflunisal have a documented moderate interaction in FDA labeling.

FDA drug labeling documents a moderate-severity interaction between Oxaprozin and Diflunisal. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.

Drug A

Oxaprozin

Nonsteroidal Anti-Inflammatory Drug (NSAID)

Drug B

Diflunisal

Nonsteroidal Anti-Inflammatory Drug (NSAID)

How They Interact

Taking two similar pain relievers together increases the risk of stomach damage without providing any extra pain relief. This can lead to serious issues like stomach ulcers or bleeding.

What To Do

Avoid taking these two medications at the same time to prevent unnecessary damage to your digestive system.

FDA Label Information

NSAIDs and Salicylates Clinical Impact: Concomitant use of oxaprozin with other NSAIDs or salicylates (e.g., diflunisal, salsalate) increases the risk of GI toxicity, with little or no increase in efficacy [ see Warnings and Precautions (5.2) ] .

Oxaprozin Also Interacts With

View all Oxaprozin interactions →

Frequently Asked Questions

Can I take Oxaprozin and Diflunisal together?

This is a moderate interaction. Avoid taking these two medications at the same time to prevent unnecessary damage to your digestive system.

How serious is the interaction between Oxaprozin and Diflunisal?

This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.

Why do Oxaprozin and Diflunisal interact?

Taking two similar pain relievers together increases the risk of stomach damage without providing any extra pain relief. This can lead to serious issues like stomach ulcers or bleeding.

Understanding the Oxaprozin and Diflunisal Interaction

FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Oxaprozin belongs to the Nonsteroidal Anti-Inflammatory Drug (NSAID) class and Diflunisal belongs to the Nonsteroidal Anti-Inflammatory Drug (NSAID) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Taking two similar pain relievers together increases the risk of stomach damage without providing any extra pain relief. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.

Context around a specific patient determines real-world impact. Oxaprozin has 15 total documented interactions on file in this dataset, and Diflunisal has 17. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Avoid taking these two medications at the same time to prevent unnecessary damage to your digestive system. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.

An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Oxaprozin or Diflunisal based on a web page, speak with your prescriber or pharmacist before making any change.

Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.