People who take nonsteroidal anti-inflammatory drugs (NSAIDs) (other than aspirin) such as mefenamic acid may have a higher risk of having a heart attack or a stroke than people who do not take these medications. These events may happen without warning and may cause death. This risk may be higher for people who take NSAIDs for a long time. Do not take an NSAID such as mefenamic acid if you have recently had a heart attack, unless directed to do so by your doctor. Tell your doctor if you or anyone in your family has or has ever had heart disease, a heart attack, or a stroke, if you smoke, and if you have or have ever had high cholesterol, high blood pressure, or diabetes. Get emergency medical help right away if you experience any of the following symptoms: chest pain, shortness of breath, weakness in one part or side of the body, or slurred speech.
If you will be undergoing a coronary artery bypass graft (CABG; a type of heart surgery), you should not take mefenamic acid right before or right after the surgery.
NSAIDs such as mefenamic acid may cause ulcers, bleeding, or holes in the stomach or intestine. These problems may develop at any time during treatment, may happen without warning symptoms, and may cause death. The risk may be higher for people who take NSAIDs for a long time, are older in age, have poor health, or who drink large amounts of alcohol while taking mefenamic acid. Tell your doctor if you take any of the following medications: anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven); aspirin; other NSAIDs such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn); oral steroids such as dexamethasone, methylprednisolone (Medrol), and prednisone (Rayos); selective serotonin reuptake inhibitors (SSRIs) such as citalopram (Celexa), fluoxetine (Prozac, Sarafem, Selfemra, in Symbyax), fluvoxamine (Luvox), paroxetine (Brisdelle, Paxil, Pexeva), and sertraline (Zoloft); or serotonin norepinephrine reuptake inhibitors (SNRIs) such as desvenlafaxine (Khedezla, Pristiq), duloxetine (Cymbalta), and venlafaxine (Effexor XR). Also tell your doctor if you have or have ever had ulcers, bleeding in your stomach or intestines, or other bleeding disorders. If you experience any of the following symptoms, stop taking mefenamic acid and call your doctor: stomach pain, heartburn, vomit that is bloody or looks like coffee grounds, blood in the stool, or black and tarry stools.
Keep all appointments with your doctor and the laboratory. Your doctor will monitor your symptoms carefully and will probably order certain tests to check your body's response to mefenamic acid. Be sure to tell your doctor how you are feeling so that your doctor can prescribe the right amount of medication to treat your condition with the lowest risk of serious side effects.
Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with mefenamic acid and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website ( https://www.fda.gov/Drugs/DrugSafety/ucm085729.htm ) or the manufacturer's website to obtain the Medication Guide.
Why is this medicine prescribed?
Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. It works by stopping the body's production of a substance that causes pain, fever, and inflammation.
Are there other uses for this medicine?
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
How should this medicine be used?
Mefenamic acid comes as a capsule to take by mouth. It is usually taken with food every 6 hours as needed for up to 1 week. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take mefenamic acid exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
What special precautions should I follow?
Before taking mefenamic acid,
- tell your doctor and pharmacist if you are allergic to mefenamic acid, aspirin or other NSAIDs such as ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn), any other medications, or any of the inactive ingredients in mefenamic acid capsules. Ask your pharmacist for a list of the inactive ingredients.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention the medications listed in the IMPORTANT WARNING section and any of the following: antacids; angiotensin-converting enzyme (ACE) inhibitors such as benazepril (Lotensin, in Lotrel), captopril, enalapril (Vasotec, in Vaseretic), fosinopril, lisinopril (in Zestoretic), moexipril (Univasc), perindopril (Aceon, in Prestalia), quinapril (Accupril, in Quinaretic), ramipril (Altace), and trandolapril (Mavik, in Tarka); amiodarone (Cordarone, Nexterone, Pacerone); angiotensin receptor blockers such as azilsartan (Edarbi, in Edarbyclor), candesartan (Atacand, in Atacand HCT), eprosartan (Teveten), irbesartan (Avapro, in Avalide), losartan (Cozaar, in Hyzaar), olmesartan (Benicar, in Azor, in Benicar HCT, in Tribenzor), telmisartan (Micardis, in Micardis HCT, in Twynsta); beta blockers such as atenolol (Tenormin, in Tenoretic), labetalol (Trandate), metoprolol (Lopressor, Toprol XL, in Dutoprol), nadolol (Corgard, in Corzide), and propranolol (Hemangeol, Inderal, InnoPran); atazanavir (Reyataz, in Evotax); clopidogrel (Plavix); diuretics ('water pills'), efavirenz (Sustiva, in Atripla); fluconazole (Diflucan); fluvastatin (Lescol); metronidazole (Flagyl); lithium (Lithobid); lovastatin (Altoprev, Mevacor); methotrexate (Otrexup, Rasuvo, Trexall); ritonavir (Norvir, in Kaletra); sulfamethoxazole (in Bactrim, in Septra); sulfinpyrazone (no longer available in U.S.; Anturane); trimethoprim (Primsol, in Bactrim, in Septra); and zafirlukast (Accolate). Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.
- tell your doctor if you have or have ever had any of the conditions mentioned in the IMPORTANT WARNING section or asthma, especially if you also have frequent stuffed or runny nose or nasal polyps (swelling of the inside of the nose); heart failure; swelling of the hands, feet, ankles, or lower legs (fluid retention); or liver or kidney disease.
- tell your doctor if you are pregnant, plan to become pregnant; or are breast-feeding. Mefenamic acid may harm the fetus and cause problems with delivery if it is taken around 20 weeks or later during pregnancy. Do not take mefenamic acid around or after 20 weeks of pregnancy, unless you are told to do so by your doctor. If you become pregnant while taking mefenamic acid, call your doctor.
- talk to your doctor about the risks and benefits of taking mefenamic acid if you are 75 years of age or older. Do not take this medication for a longer period of time or at a higher dose than recommended by your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking mefenamic acid.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget to take a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What should I do in case of overdose?
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
Symptoms of overdose may include the following:
- extreme tiredness
- nausea
- vomiting
- stomach pain
- vomit that is bloody or looks like coffee grounds
- black, tarry, or bloody stools
- slowed breathing
- coma (loss of consciousness for a period of time)
What side effects can this medicine cause?
Mefenamic acid may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- diarrhea
- constipation
- gas or bloating
- headache
- dizziness
- nervousness
- ringing in the ears
Some side effects can be serious. If you experience any of the following symptoms or those mentioned in the IMPORTANT WARNING section, call your doctor immediately. Do not take any more mefenamic acid until you speak to your doctor.
- blurred vision
- unexplained weight gain
- shortness of breath or difficulty breathing
- swelling of feet, ankles, or lower legs
- fever
- blisters
- rash
- itching
- hives
- swelling of the eyes, face, lips, tongue, throat, hands, or arms
- difficulty breathing or swallowing
- pale skin
- fast heartbeat
- excessive tiredness
- unusual bleeding or bruising
- lack of energy
- nausea
- loss of appetite
- pain in the upper right part of the stomach
- flu-like symptoms
- yellowing of the skin or eyes
- cloudy, discolored, or bloody urine
- back pain
- difficult or painful urination
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( http://www.fda.gov/Safety/MedWatch ) or by phone (1-800-332-1088).
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( http://goo.gl/c4Rm4p ) for more information if you do not have access to a take-back program.
What other information should I know?
Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking mefenamic acid.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.