GENERIC NAME: Mefenamic Acid

COMMON BRANDS: Ponstel, Ponstan

Mefenamic acid is an oral prescription drug belongs to a class of medications known as nonsteroidal anti-inflammatory drugs (NSAIDs). It is used for relief of mild to moderate pain, such as muscular aches and pains, menstrual cramps, headaches, and dental pain. It works by decreasing the amount of prostaglandins (cyclooxygenase COX-1 and COX-2) produced in your body.

Mefenamic acid is available in both brand-name version and generic-name version. It is sold under the common brand name “Ponstel”. The generic drugs usually cost less than the brand name version.

What is Mefenamic Acid used for?

Mild to moderate pain: It is used to relieve pain in people who are least 14 years old for various conditions like a headache, dental pain, muscle aches, or arthritis not more than seven days.

Primary dysmenorrhea: It is used to treat menstrual pain or cramps for not more than two to three days.

Primary dysmenorrhea is a pain in the lower abdomen that usually occurs before or during menstruation, in the absence of other diseases such as endometriosis.

How to use Mefenamic Acid?

Read the medication guide carefully given by your pharmacist before you start taking mefenamic acid and whenever you get a refill. If you have any problem or you do not understand any part, discuss with your doctor or pharmacist.

Take this medication orally, usually 3-4 times in a day with a full glass of water or as advised by your doctor. Do not lie down wait for at least 10 minutes after taking this drug. To avoid gastrointestinal problems (like stomach upset) take this drug with food or milk. Avoid taking mefenamic acid with antacids unless directed by your doctor. Some antacids may change the amount of mefenamic acid absorbed by your body.

Mefenamic acid may cause stomach or intestinal bleeding, which can be fatal. Older adults are more sensitive to these side effects. To reduce the risk of GIT bleeding and other side effects, take this medication at a lower dose for the shorter duration.

Do not change your dose or take it more frequently than directed by your doctor. Do not this medication more than seven days at a time.

Pain medication works best if they are used with the first signs of pain. If you wait until your pain worsens, the medicine may not work well.

If you are using this medication for dysmenorrhea (painful periods), take your first dose as soon as your pain starts. Do not take more than 2-3 days of your menses.

Inform your doctor if your pain remains or get worst or if you develop any new symptoms.

What are the side effects of Mefenamic Acid?

The most common side effects observed with the use of this drug are nausea, vomiting, stomach upset, mild heartburn, bloating, gas, constipation, diarrhoea, dizziness, headache, mild itching or rash or ringing in your ears. If any of these effects remain or get worse, notify your doctor immediately.

Get emergency medical assistance if you notice symptoms of GIT bleeding or ulcers such as stomach pain or upset stomach, black, sticky stools and vomiting up blood.

This drug rarely causes severe, possibly fatal liver disease symptoms like persistent nausea/vomiting, weakness, severe stomach/abdominal pain, dark urine, yellowing eyes/skin. If you notice any of these severe side effects, stop taking mefenamic acid and consult your doctor or pharmacist right away.

Get medical help immediately, if you have signs of a heart attack or stroke like chest pain radiating to your shoulder or jaw, weakness on one side of the body or sudden numbness, slurred speech, leg swelling, breathlessness.

Stop using mefenamic acid and inform your doctor immediately, if you have any severe side effects like changes in your vision, symptoms of heart failure (like shortness of breath, swelling or rapid weight gain), first sign of any skin rash, signs of kidney problems (like change in the amount of urine), easy bruising/bleeding, signs of infection (e.g., fever, persistent sore throat), and unexplained stiff neck.

Get medical assistance promptly if you have signs of an allergic reaction like sneezing, runny or stuffy nose, wheezing or trouble breathing, swelling of your face, lips, tongue, or throat.

Inform your doctor instantly if you notice any signs or symptoms of unexplained weight gain or edema.

This document does not include all possible side effects. If you see other side effects not listed above, reach out to your doctor or pharmacist.

What are the precautions while using Mefenamic Acid?

Inform your doctor/pharmacist before taking mefenamic acid, if you are allergic to it; or if you have other allergies (including aspirin and other NSAIDs). This drug may also contain some inactive ingredients that can cause allergic reactions or other problems. Talk to your doctor/pharmacist for more information.

Inform your doctor/pharmacist about all the products you are using including prescription, non-prescription, vitamins, nutritional supplements, and herbal products.

Before taking mefenamic acid, discuss with your doctor or pharmacist about your medical history especially of aspirin-sensitive asthma, severe kidney disease, recent heart bypass surgery (CABG), active bleeding/sores in stomach/intestines (ulcer, gastrointestinal bleeding), blood disorders (like anemia), high blood pressure, diabetes, liver disease, nasal polyps, obesity, tobacco use, stroke, swelling of the ankles/feet/hands.

Mefenamic acid may cause stomach or intestinal bleeding, which can be fatal, older adults are more susceptible to this condition. Regular use of this drug with alcohol and tobacco may increase your chances for stomach bleeding. Restrict the use of alcohol and stop smoking. Consult your doctor/pharmacist for further information.

This drug may cause you dizzy or drowsy, do not drive, use heavy machinery, or do anything that needs sharpness until you can do it cautiously. Limit use of alcoholic beverages. Speak to your doctor if you are using marijuana.

NSAIDs like mefenamic acid sometimes can cause kidney problem which is more likely to occur if you have kidney disease or have heart failure, in severe dehydration, or an older adult. To avoid kidney problem take plenty of fluids. Notify your doctor instantly if you have a change in the amount of urine.

Older adults are susceptible to the side effects of this drug especially to stomach bleeding and kidney problems. Therefore, caution is recommended while using this drug in older adults.

During pregnancy, use this medication only when benefits outweigh the risk. It is not advised to use this drug during the first and last trimesters of pregnancy as it may harm to the fetus and interference with normal labour/delivery.

This drug may pass into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breastfeeding.

What are the drug interactions of Mefenamic Acid?

Mefenamic acid may interact with other medications, herbs, or vitamins you may be using. A drug interaction is when a substance changes the way a drug works which can be harmful or block the drug from working well.

Do not start, stop, or alter the dose of the drug without consulting your doctor because your doctor may be monitoring you for all possible drug interactions.

Some products that may interact with mefenamic acid are aliskiren, ACE inhibitors (like captopril, lisinopril), fluconazole, angiotensin II receptor blockers (like losartan, valsartan), cidofovir, corticosteroids (like prednisone), lithium or diuretics (like furosemide), ketorolac, and methotrexate.

Taking blood thinners” such as dabigatran/enoxaparin/warfarin and anti-platelet drugs such as clopidogrel with mefenamic acid increases the risk of severe stomach bleeding.

Take advice from your doctor/pharmacist before using any over-the-counter medicine for cold, allergy, or pain. Many over-the-counter medications contain aspirin or other NSAIDs similar to mefenamic acid. Taking these products together with mefenamic acid can increase the concentration of mefenamic acid in your body which results in more side effects. Read the medication label carefully to check if the medicine contains aspirin or other NSAIDs.

Mefenamic acid may intervene with specific laboratory tests (like urine bile test), giving a false test result. Assure that laboratory personnel, and all your doctors know you use this drug.


Heart risk warning:

Mefenamic acid may increase the risk of heart problems, such as blood clot, heart attack, stroke, or heart failure which can be fatal. The risk may increase if you already have heart disease or have taken mefenamic acid for an extended period or at high doses.

This drug is contraindicated for the treatment of pain before coronary artery bypass graft (CABG) surgery (heart surgery is done to increase blood flow to the heart). Taking this drug before surgery will increase the risk of heart attack and stroke.

Gastrointestinal warning:

This drug may increase your risk of stomach problems, like bleeding, or peptic ulcers which can be fatal. These conditions can occur at any time and without any warning signs. If you are above 65 years, you may have a greater chance for severe stomach issues.

What are the forms and strengths of Mefenamic Acid?

Generic: Mefenamic acid
Form: Oral capsule
Strength: 250mg

Brand: Ponstel
Form: Oral capsule
Strength: 250mg

Brand: Ponstan
Form: Oral tablet
Strength: 500mg

What is the dosage of Mefenamic Acid?

For Mild to Moderate Pain:

Adult (18 years and above):

Initial dose: Take 500mg followed by 250mg every 6 hours as needed.

Children (14–17 years):

Initial dose: Take 500mg followed by 250mg every 6 hours as needed.

Children (0–13 years):

Avoid use of this drug in children below 14 years of age, as the studies have not been established yet.

Note: Do not take mefenamic acid for longer than seven days.

For Menstrual Pain:

Adult (18 years and above):

Initial dose: Take 500mg followed by 250mg every 6 hours as needed.

Children (14 to 17 years):

Initial dose: Take 500mg followed by 250mg every 6 hours as needed.

Children (0–13 years):

Avoid use of this drug in children below 14 years of age, as the studies have not been established yet.

Note: Start this medication when your bleeding and cramps start. Do not take mefenamic acid for longer than three days.

Most common questions asked about Mefenamic Acid / Q&A’s:

What are the symptoms of Mefenamic Acid overdose?

Mefenamic acid overdose symptoms may include extreme tiredness, stomach pain, nausea, vomiting, vomit that is bloody or looks like coffee grounds, black, tarry, or bloody stools, slowed breathing and coma. Seek a medical emergency as soon as possible if you experience any of these symptoms.


TheMedPharma has made every effort to make sure that all the information is factually correct, comprehensive, and up-to-date. However, this website should not be considered as a substitute for the advice, knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or licensed health care professional before taking any medication. The drug information contained herein is subjected to changes if required. The lack of warnings or other information for a given drug does not mean that the drug or its combination is safe, effective or appropriate for use in all patients.