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diclofenac vs diflunisal

Side-by-side comparison of diclofenac and diflunisal Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

Drug Class
diclofenac Nonsteroidal Anti-Inflammatory Drug (NSAID)
diflunisal Nonsteroidal Anti-Inflammatory Drug (NSAID)
Type
diclofenac Over-the-Counter
diflunisal Prescription
Summary
diclofenac

Diclofenac is a gel that helps with arthritis pain in your hands, wrists, elbows, feet, ankles, or knees. It belongs to a class of drugs called NSAIDs.

diflunisal

Diflunisal is a medicine that can help with pain and swelling. It belongs to a class of drugs called NSAIDs.

What It Treats
diclofenac

This medicine temporarily relieves arthritis pain. It is only for pain in your hands, wrists, elbows, feet, ankles, or knees. It may take up to 7 days to start working. If you still have pain after 7 days, stop using it.

diflunisal

Diflunisal can help with mild to moderate pain. It can also treat the symptoms of osteoarthritis and rheumatoid arthritis. You should use the lowest dose that works for you, for the shortest time needed.

How It Works
diclofenac

Diclofenac is an NSAID. It reduces pain and swelling by blocking substances in the body that cause inflammation.

diflunisal

Diflunisal reduces pain and swelling by blocking the production of certain chemicals in your body. These chemicals cause inflammation and pain. By blocking them, diflunisal helps to relieve your symptoms.

Common Side Effects
diclofenac
  • Pain
  • Headache
diflunisal
  • Nausea
  • Vomiting
  • Upset stomach
  • Stomach pain
  • Diarrhea
FAERS Reports
diclofenac
  • Medicine not working 13,689
  • Pain 12,281
  • Tiredness 11,317
  • Rheumatoid arthritis 9,240
  • Rash 8,747
diflunisal
  • Feeling sick to your stomach 66
  • Feeling very tired 57
  • Discomfort or aching 50
  • Allergic reaction to the medicine 47
  • Pain in your head 45
Serious Warnings
diclofenac

There are no boxed warnings in the provided data.

diflunisal

NSAIDs like diflunisal can increase your risk of heart problems like heart attack and stroke, which can be deadly. This risk is higher if you take it for a long time. You should not take diflunisal if you are having heart bypass surgery. NSAIDs also raise your risk of serious stomach problems like bleeding and ulcers, which can also be deadly. Older adults are at higher risk for these stomach problems.

Pregnancy
diclofenac

There is no information about pregnancy or breastfeeding in the provided data.

diflunisal

Tell your doctor if you are pregnant or plan to become pregnant. Taking diflunisal late in pregnancy may harm your baby. It is not known if diflunisal passes into breast milk, so talk to your doctor before breastfeeding.

Also Compare — Nearby Drugs

How to Read This diclofenac vs diflunisal Comparison

diclofenac is classified in the Nonsteroidal Anti-Inflammatory Drug (NSAID) drug class, while diflunisal sits within the Nonsteroidal Anti-Inflammatory Drug (NSAID) class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. Both drugs are split between OTC and prescription status, which affects access and supervision.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, diclofenac has 55,274 submissions while diflunisal has 265. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between diclofenac and diflunisal — always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.