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.
Side Effects Of Mefenamic Acid
Mefenamic acid may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- gas or bloating
- ringing in the ears
Some side effects can be serious. If you experience any of the following symptoms or those mentioned in the 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
- 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
- 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
Warnings & Precautions
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, especially if you are in the last few months of your pregnancy, you plan to become pregnant, or you are breastfeeding. 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.
Dosage Of Mefenamic Acid
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.
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.
All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.