Mefenamic acid (By mouth)
Mefenamic Acid (mef-e-NAM-ik AS-id)
Treats pain, including menstrual pain. This is an NSAID.
When This Medicine Should Not Be Used
How to Use This Medicine
- Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
- It is best to take this medicine with food or milk.
- This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
- Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
- Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
- Do not use any other NSAID unless your doctor says it is okay. Some other NSAIDs are aspirin, diflunisal, ibuprofen, naproxen, or salsalate.
- Some medicines can affect how mefenamic acid works. Tell your doctor if you are using any of the following:
- Aspirin, cyclosporine, digoxin, fluconazole, lithium, methotrexate, pemetrexed, trimethoprim
- Blood pressure medicine
- Blood thinner (including warfarin)
- Diuretic (water pill)
- Medicine to treat depression
- Steroid medicine
- Do not drink alcohol while you are using this medicine.
Warnings While Using This Medicine
- Tell your doctor if you are pregnant. Do not use this medicine during the later part of a pregnancy, unless your doctor tells you to.
- Tell your doctor if you are breastfeeding, or if you have kidney disease, liver disease, asthma, high blood pressure, heart or blood vessel problems, heart failure, a recent heart attack, or a history of stomach ulcers or bleeding problems. Tell your doctor if you smoke or drink alcohol.
- This medicine may cause the following problems:
- Increased risk of blot clots, heart attack, stroke, or heart failure
- Bleeding problems, including stomach and bowel bleeding or ulcer
- Liver problems
- High blood pressure
- Kidney problems
- Serious skin reactions
- Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
- Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
- Keep all medicine out of the reach of children. Never share your medicine with anyone.
Possible Side Effects While Using This Medicine
Call your doctor right away if you notice any of these side effects:
- Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
- Blistering, peeling, red skin rash
- Bloody or black, tarry stools, severe stomach pain, vomiting blood or material that looks like coffee grounds
- Change in how much or how often you urinate
- Chest pain that may spread, trouble breathing, coughing up blood, unusual sweating, fainting
- Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
- Numbness or weakness on one side of your body, sudden or severe headache, problems with vision, speech, or walking
- Rapid weight gain, swelling in your hands, ankles, or feet
- Unusual bleeding, bruising, or weakness
If you notice these less serious side effects, talk with your doctor:
- Constipation, diarrhea
If you notice other side effects that you think are caused by this medicine, tell your doctor
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
- Last reviewed on 10/4/2017
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