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Last Updated: 12/23/2024

Mefenamic acid

Drug Name(s): generic only

Class: NSAIDs

Used to treat mild to moderate pain; use for no more than a week.

Dosage

Form(s): capsule

500 mg starting dose, then 250 mg every 6 hours as needed, for up to 7 days

 

Special Instructions

Do not take with other prescription or over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs). Take at the same time every day. Take with food, milk or an antacid to prevent gastrointestinal symptoms. Do not take for more than seven days unless directed by your doctor.

Potential Side Effects

Abdominal pain, cramps or discomfort; constipation; diarrhea; dizziness; drowsiness; flatulence; gastrointestinal bleeding; headache; heartburn; high blood pressure; indigestion; itching; nausea or vomiting; peptic ulcer; rash; ringing in ears; swelling of feet

Be Aware

Before taking this or any NSAID, tell your doctor if you are or may become pregnant, are 65 or older, drink heavily; have heart, liver, kidney, GI, or blood pressure problems; or have asthma, chronic lung disease, reflux disease, Crohn’s disease, ulcer colitis or an active infection.

Tell your doctor if you are using any of the following before starting this or any NSAID: blood thinners (including warfarin), ACE inhibitors, antimaniac agents (mood stabilizers), blood pressure medicines, lithium or furosemide, medicines that affect liver enzymes, methotrexate or St. John’s Wort. 

Like all NSAIDs, except aspirin, this drug may cause an increased risk of serious blood clots, heart attack and stroke, which can be fatal. The risk is greatest for patients who have or are at risk for cardiovascular disease. NSAIDs also raise the risk of gastrointestinal (GI) bleeding. 

Stop taking this drug and call your doctor if you experience dark or bloody stool or urine, yellow skin or eyes, unusual weight gain, itch or rash with a fever; swelling of the arms, legs and feet; lightheadness or balance problems

The Arthritis Foundation’s Drug Guide is meant for education — not self-medicating. The Arthritis Foundation does not endorse any products mentioned in this guide. While we endeavor to keep the information up to date, we make no representations or warranties about the completeness of the information provided.