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Common Brand Name(s): Ponstan
This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Nonsteroidal anti-inflammatory drugs (including mefenamic acid) may rarely increase the risk for a (sometimes fatal) heart attack or stroke. This effect does not apply to low-dose aspirin. (See Drug Interactions section.) This effect can happen at any time while taking this drug but is more likely if you take it for a long time. The risk may be greater in older adults or if you have heart disease or increased risk for heart disease (for example, due to smoking, family history of heart disease, or conditions such as high blood pressure or diabetes). Do not take this drug right before or after heart bypass surgery (CABG). Also, this drug may rarely cause serious (rarely fatal) bleeding from the stomach or intestines. This bleeding can occur without warning symptoms at any time during treatment.
Stop taking this medication and seek immediate medical attention if you notice any of the following rare but very serious side effects: chest pain, severe dizziness, trouble breathing, weakness on one side of the body, sudden vision changes, trouble speaking, black stools, persistent stomach/abdominal pain, vomit that looks like coffee grounds. (See also Precautions section.)
Talk with your doctor or pharmacist about the risks and benefits of treatment with this medication.
Mefenamic acid is used for the short-term treatment of mild to moderate pain from various conditions. It is also used to decrease pain and blood loss from menstrual periods.
Mefenamic acid is known as a nonsteroidal anti-inflammatory drug (NSAID).
This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.
This drug may also be used for gout attacks.
Read the Medication Guide provided by your pharmacist before you start using mefenamic acid and each time you get a refill. If you have any questions, consult your doctor or pharmacist.
Take this medication by mouth, usually 4 times a day with a full glass of water (8 ounces or 240 milliliters) or as directed by your doctor. Do not lie down for at least 10 minutes after taking this drug. If stomach upset occurs, take this medication with food or milk. Do not take mefenamic acid with antacids unless directed by your doctor. Certain antacids may change the amount of mefenamic acid absorbed by the body.
Dosage is based on your medical condition and response to therapy. To reduce your risk of stomach bleeding and other side effects, take this medication at the lowest effective dose for the shortest possible time. Do not increase your dose, take it more frequently, or take it for a longer time than prescribed. This medication usually should not be taken for more than 7 days at a time.
If you are taking this drug on an "as needed" basis (not on a regular schedule), remember that pain medications work best if they are used as the first signs of pain occur. If you wait until the symptoms have worsened, the medicine may not work as well.
If you are using this medication for painful periods, take your first dose as soon as your period starts or pain begins. Usually, you will only need to take it for the first 2 to 3 days of your period.
Inform your doctor if your pain persists or worsens or if you develop new symptoms.
See also Warning section.
Upset stomach, nausea, heartburn, dizziness, drowsiness, diarrhea, and headache may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
This medication may raise your blood pressure. Check your blood pressure regularly and tell your doctor if the results are high.
Tell your doctor right away if any of these unlikely but serious side effects occur:
Stop taking mefenamic acid and tell your doctor right away if any of these rare but very serious side effects occur:
This drug may rarely cause serious, possibly fatal liver disease. If you notice any of the following rare but very serious side effects, stop taking mefenamic acid and consult your doctor or pharmacist right away:
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking mefenamic acid, tell your doctor or pharmacist if you are allergic to it; or to aspirin or other NSAIDs (e.g., ibuprofen, naproxen, celecoxib); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have:
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
Kidney problems can sometimes occur with the use of NSAID medications, including mefenamic acid. Problems are more likely to occur if you are dehydrated, have heart failure or kidney disease, are an older adult, or if you take certain medications (see also Drug Interactions section). Drink plenty of fluids as directed by your doctor to prevent dehydration and tell your doctor right away if you have a change in the amount of urine.
Before having surgery, tell your doctor or dentist that you are using this medication.
This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).
This medicine may cause stomach bleeding. Daily use of alcohol and tobacco, especially when combined with this medicine, may increase your risk for stomach bleeding. Limit alcohol and stop smoking. Consult your doctor or pharmacist for more information.
This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.
Older adults may be at greater risk for stomach/intestinal bleeding, kidney problems, heart attack, and stroke while using this drug.
Before using this medication, women of childbearing age should talk with their doctor(s) about the benefits and risks. Tell your doctor if you are pregnant or if you plan to become pregnant. This medication may harm an unborn baby and cause problems with normal labor/delivery. It is not recommended for use in pregnancy from 20 weeks until delivery. If your doctor decides that you need to use this medication between 20 and 30 weeks of pregnancy, you should use the lowest effective dose for the shortest possible time. You should not use this medication after 30 weeks of pregnancy.
This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include:
This medication may increase the risk of bleeding when taken with other drugs that also may cause bleeding. Examples include anti-platelet drugs such as clopidogrel, "blood thinners" such as dabigatran/enoxaparin/warfarin, among others.
Check all prescription and nonprescription medicine labels carefully since many medications contain pain relievers/fever reducers (aspirin, NSAIDs such as celecoxib or ibuprofen). These drugs are similar to mefenamic acid and may increase your risk of side effects if taken together. However, if your doctor has directed you to take low-dose aspirin to prevent heart attack or stroke (usually 81-162 milligrams a day), you should continue taking the aspirin unless your doctor instructs you otherwise. Ask your doctor or pharmacist for more details.
This medication may interfere with certain laboratory tests (e.g., urine bile test), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Alberta residents can call PADIS (Poison and Drug Information Service) 24 hours a day at 1-800-332-1414. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe stomach pain, vomit that looks like coffee grounds, extreme drowsiness, slow/shallow breathing, seizures.
Do not share this drug with others.
Laboratory and/or medical tests (e.g., blood pressure, complete blood count, liver and kidney function tests) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
If you are taking this drug on a regular schedule (not "as needed") and you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
If you have questions about missing a dose or you don't have more medication, contact your healthcare provider or pharmacist.
Store at room temperature between 68-77 degrees F (20-25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised August 2021.
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Conditions of use: The information in this database is intended to supplement, not substitute for the expertise and judgment of healthcare professionals. The information in not intend to cover all possible uses, directions, precautions, drug interactions or adverse effects nor should it be construed in indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.
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