Mefenamic Acid: What It Is and When to Use It

If you’ve ever been prescribed a pill called mefenamic acid, you probably wonder what it actually does. In simple terms, it’s a non‑steroidal anti‑inflammatory drug (NSAID) that helps reduce pain, swelling, and fever. Doctors often turn to it for menstrual cramps, dental pain, or injuries that cause inflammation. It works by blocking chemicals in your body called prostaglandins, which are partly responsible for pain signals.

What makes mefenamic acid a bit different from other NSAIDs is its longer half‑life, so it stays in your system a little longer. That can be handy if you need steady relief throughout the day, but it also means you have to watch the dose carefully. The standard adult dose is usually 250 mg taken two or three times a day, but the exact amount can change based on your weight, age, and kidney health.

How to Dose Mefenamic Acid Safely

Start with the lowest dose that gives you relief. For most adults, that’s 250 mg every 6‑8 hours. If you’re under 50 kg (about 110 lb), your doctor might suggest 125 mg instead, especially if you have a sensitive stomach. Don’t exceed 1 g (1000 mg) in a 24‑hour period unless a medical professional tells you it’s okay.

Take the tablet with food or a glass of milk. Food helps protect your stomach lining, which can be irritated by NSAIDs. If you miss a dose, take it as soon as you remember—unless it’s almost time for your next dose. In that case, skip the missed one; don’t double up.

People with kidney problems need extra caution. Mefenamic acid is cleared mainly by the kidneys, so impaired function can cause the drug to build up. If you have chronic kidney disease, your doctor may pick a different pain reliever or lower the dose significantly.

Potential Side Effects and Interactions

Like any medication, mefenamic acid can cause side effects. The most common are stomach upset, nausea, and mild heartburn. If you notice blood in your stool, black or tarry stools, or vomiting blood, stop the medication and call a doctor right away—those can be signs of serious bleeding.

Other possible issues include headache, dizziness, or a rash. Rarely, it can affect kidney function or raise blood pressure, so keep an eye on any swelling in your ankles or sudden weight gain.

What you eat and other drugs matter, too. Avoid alcohol while taking mefenamic acid because it raises the risk of stomach bleeding. Anticoagulants like warfarin, other NSAIDs, and certain blood pressure meds can also interact. Let your pharmacist know every medication you’re on, including over‑the‑counter supplements.

Pregnant or breastfeeding women should generally steer clear of mefenamic acid unless a doctor says it’s essential. The drug can affect the developing fetus and pass into breast milk.

In summary, mefenamic acid can be a solid choice for short‑term pain relief if you follow dosing rules, take it with food, and stay aware of side effects. Always talk to a healthcare provider if you have kidney issues, are on blood thinners, or notice any alarming symptoms. With the right precautions, you can use it safely and get back to feeling normal faster."