diclofenac vs mefenamic acid
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of diclofenac and mefenamic acid. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
NSAIDs with short elimination half-lives (e.g., diclofenac, indomethacin) should be avoided for a period of two days before, the day of, and two days following administration of pemetrexed.
Voltaren, Cataflam
Ponstel
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.
Mefenamic acid is a medicine used to treat mild to moderate pain and menstrual cramps. It is a type of nonsteroidal anti-inflammatory drug (NSAID).
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.
Mefenamic acid is used to relieve mild to moderate pain in people 14 years and older. It should not be used for more than 7 days. It is also used to treat menstrual cramps.
Diclofenac is an NSAID. It reduces pain and swelling by blocking substances in the body that cause inflammation.
Mefenamic acid reduces pain and inflammation in the body. It does this by blocking substances in the body that cause pain and swelling. This medicine helps to reduce pain and discomfort.
- • Pain
- • Headache
- • Abdominal pain
- • Constipation
- • Diarrhea
- • Upset stomach
- • Gas
- Pain 12,281
- Fatigue 11,317
- Rheumatoid Arthritis 9,241
- Rash 8,747
- Arthralgia 8,640
- Nausea 296
- Fatigue 253
- Headache 227
- Pain 202
- Dizziness 177
No specific warnings noted.
Mefenamic acid may increase the risk of serious heart problems, including heart attack and stroke, which can be fatal. This risk may occur early in treatment and may increase with longer use. You should not take this medicine if you are having heart bypass surgery. Mefenamic acid can also increase the risk of serious stomach and intestinal problems, including bleeding, ulcers, and holes, which can be fatal. These problems can occur without warning. The elderly and those with a history of stomach ulcers or bleeding are at higher risk.
No pregnancy information available.
Tell your doctor if you are pregnant or plan to become pregnant. Mefenamic acid may harm your unborn baby. It is not known if mefenamic acid passes into breast milk. Talk to your doctor before breastfeeding.
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How to Read This diclofenac vs mefenamic acid Comparison
diclofenac is classified in the Nonsteroidal Anti-Inflammatory Drug (NSAID) drug class, while mefenamic acid 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 50,226 submissions while mefenamic acid has 1,155. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to taking two different nsaid pain relievers together increases the risk of serious side effects like stomach bleeding and kidney problems.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for diclofenac or mefenamic acid.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.