Mefenamic acid

Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that is used for a short time (7 days or less) to treat mild to moderate pain in adults and children who are at least 14 years old. Mefenamic acid is also used to treat menstrual pain.

Mefenamic acid may also be used for reasons not mentioned in this medication guide.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may change your dose from time to time. Use the lowest dose that works for your condition.

Mefenamic acid should not be used for more than 7 days. Follow your doctor's dosing instructions very carefully.

If you take mefenamic acid for a long time, you may need to have medical tests done often.

This medicine can affect the results of some medical tests. Inform any doctor who treats you that you are using mefenamic acid.

Store at room temperature, away from moisture and heat. Keep the bottle tightly closed when not in use.

Mefenamic acid can raise your chances of having a fatal heart attack or stroke. Do not use mefenamic acid right before or after heart bypass surgery (coronary artery bypass graft, or CABG). Mefenamic acid may also lead to stomach or intestinal bleeding, which can be fatal.

Mefenamic acid can increase your risk of a fatal heart attack or stroke, even if you have no risk factors. Do not use this medicine just before or after heart bypass surgery (coronary artery bypass graft, or CABG).

Mefenamic acid may also lead to stomach or intestinal bleeding, which can be fatal. These issues can happen without warning while you are using mefenamic acid, especially in older adults.

You should not use mefenamic acid if you are allergic to it, or if you have:

• an active ulcer or stomach bleeding;
• a bowel disorder such as ulcerative colitis or inflammatory bowel disease;
• kidney disease; or
• a history of asthma attack or severe allergic reaction after taking aspirin or an NSAID.

Tell your doctor if you have ever had:

• heart disease, high blood pressure, high cholesterol, diabetes, or if you smoke;
• a heart attack, stroke, or blood clot;
• stomach ulcers or bleeding;
• asthma;
• fluid retention; or
• liver disease.

If you are pregnant, you should not take mefenamic acid unless your doctor tells you to. Taking an NSAID during the last 20 weeks of pregnancy can cause serious heart or kidney problems in the unborn baby and possible complications with your pregnancy.

Tell your doctor if you are breastfeeding.

Mefenamic acid is not approved for use by anyone younger than 14 years old.

Get emergency medical help if you have signs of an allergic reaction (sneezing, runny or stuffy nose, hives, wheezing or trouble breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Get emergency medical help if you have signs of a heart attack or stroke: chest pain spreading to your jaw or shoulder, sudden numbness or weakness on one side of the body, slurred speech, feeling short of breath.

Stop using mefenamic acid and seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

Mefenamic acid may cause serious side effects. Stop using mefenamic acid and call your doctor at once if you have:

• shortness of breath (even with mild exertion);
• swelling or rapid weight gain;
• nausea, diarrhea, flu-like symptoms (fever, swollen glands, muscle aches, severe weakness);
• a skin rash, no matter how mild;
• signs of stomach bleeding--bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;
• liver problems--loss of appetite, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
• kidney problems--little or no urination, swelling in your feet or ankles, feeling tired or short of breath;
• low red blood cells (anemia)--pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet.

Common side effects of mefenamic acid may include:

• heartburn, stomach pain, gas, nausea, vomiting;
• diarrhea, constipation; or
• dizziness.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Usual Adult Dose for Pain:

Initial dose: 500 mg orally onceFollowing initial dose: 250 mg orally every 6 hours as neededDuration of therapy: Usually not to exceed 1 weekUse: For the relief of acute pain

Usual Adult Dose for Dysmenorrhea:

Initial dose: 500 mg orally onceFollowing initial dose: 250 mg orally every 6 hours as neededDuration of therapy: 2 to 3 daysComments:-Treatment should begin at the onset of bleeding and associated symptoms.Use: For the treatment of primary dysmenorrhea

Usual Pediatric Dose for Pain:

14 years or older:-Initial dose: 500 mg orally once-Following initial dose: 250 mg orally every 6 hours as needed-Duration of therapy: Usually not to exceed 1 weekUse: For the relief of acute pain

Usual Pediatric Dose for Dysmenorrhea:

14 years or older:-Initial dose: 500 mg orally once-Following initial dose: 250 mg orally every 6 hours as needed-Duration of therapy: 2 to 3 daysComments:-Treatment should begin at the onset of bleeding and associated symptoms.Use: For the treatment of primary dysmenorrhea

Take the medicine as soon as you can, but if it's almost time for your next dose, skip the missed dose. Do not take two doses at the same time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

• Avoid drinking alcohol. It may increase your risk of stomach bleeding.

• Ask a doctor or pharmacist before using other medicines for pain, fever, swelling, or cold/flu symptoms. They may contain ingredients similar to mefenamic acid (such as aspirin, ibuprofen, ketoprofen, or naproxen).

Ask your doctor before using mefenamic acid if you are taking an antidepressant. Using certain antidepressants with an NSAID may make you bruise or bleed easily.

Tell your doctor about all your other medicines, especially:

• lithium;
• methotrexate;
• antacids such as Milk of Magnesia, Maalox, Mylanta, or Rolaids;
• a blood thinner (warfarin, Coumadin, Jantoven);
• heart or blood pressure medication, including a diuretic or "water pill"; or
• steroid medicine (such as prednisone).

This list is not complete. Other drugs may affect mefenamic acid, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.