Ponstel (Mefenamic Acid) – Oral

Warning:

Taking nonsteroidal anti-inflammatory drugs (NSAIDs) like Ponstel (mefenamic acid) can raise the risk of serious cardiovascular problems, such as blood clots, heart attack, and stroke. The risk may increase with long-term use.
Mefenamic acid should not be used to treat pain around the time of a heart surgery called coronary artery bypass graft (CABG).
NSAIDs can also cause severe gastrointestinal (GI) side effects, such as GI ulcers or bleeding. Older adults (65 years and older) and people with a history of peptic ulcer disease or GI bleeding are at greater risk for this side effect.

What Is Ponstel?

Ponstel (mefenamic acid) is a medication that relieves mild to moderate pain. It is also used to ease menstrual cramps. This medication belongs to a class of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs).

Like other NSAIDs, Ponstel reduces inflammation and eases pain. This medication is thought to work by decreasing the body’s production of prostaglandins (types of fatty acids called lipids that are made at the site of damaged tissues or infection and act as hormones, causing an inflammatory response).

Ponstel and its generic form, mefenamic acid, are prescription drugs. They come as oral capsules.

Drug Facts

Generic Name: Mefenamic Acid

Brand Name(s): Ponstel

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Nonsteroidal anti-inflammatory drug (NSAID)

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Mefenamic acid

Dosage Form(s): Capsule

What Is Ponstel Used For?

The Food and Drug Administration (FDA) approved Ponstel to relieve mild to moderate pain in adults and adolescents ages 14 and older. For this use, you’ll take Ponstel for up to one week.

Ponstel is also approved to treat primary dysmenorrhea. This is the medical term for painful menstrual cramps that are not caused by another condition.  

For each of these uses, healthcare providers will only prescribe Ponstel if its potential benefits outweigh its risks to you. They will prescribe the lowest dose needed for the shortest time possible.

How to Take Ponstel

Take Ponstel according to your healthcare provider’s instructions. This medication is typically taken every six hours as needed for up to one week. For menstrual cramps, take it at the onset of bleeding and symptoms.

You may take each dose with food to help prevent or lessen an upset stomach.

Storage

Store Ponstel capsules at room temperature (between 68 and 77 degrees F) in a tightly closed container.

Off-Label Uses

Healthcare providers sometimes prescribe Ponstel for non-FDA-approved conditions. This is known as off-label prescribing because the reason isn’t listed on the drug’s official label. 

For example, mefenamic acid has been studied for reducing the symptoms of COVID-19. In a clinical trial, this medication helped to decrease the severity of certain symptoms, such as headache and sore throat. However, more research is needed to determine Ponstel’s usefulness.

How Long Does Ponstel Take to Work?

Mefenamic acid starts working soon after the first dose. But it may take a few doses before you notice any pain relief. If the medication isn’t helping your pain or cramps, talk to your healthcare provider.

What Are the Side Effects of Ponstel?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at www.fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects of mefenamic acid may include:

  • Upset stomach, such as abdominal pain, constipation, diarrhea, heartburn, gas, nausea, or vomiting
  • Dizziness
  • Headache
  • Itchiness
  • Tinnitus (ringing in the ears)
  • Fluid retention

Severe Side Effects

The list below includes severe side effects that have been reported with the use of Ponstel or other NSAIDs. Call your healthcare provider immediately if you have serious side effects. Dial 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. 

Serious side effects of mefenamic acid and their symptoms may include:

  • Cardiovascular events such as blood clots, heart attack, or stroke: Swelling or warmth in your leg or arm, shortness of breath, chest pain or pressure, sudden weakness on one side of your body, dizziness, or confusion
  • Gastrointestinal bleeding or ulcers: Abdominal pain, bowel movements that are bloody, black, or tar-like, vomit that is bloody or looks like coffee grounds, or fatigue
  • Liver damage: Yellowing of the skin or whites of the eyes (jaundice), abdominal pain, nausea, vomiting, itchy skin, or dark urine
  • High blood pressure (hypertension): Typically no symptoms, but headache or dizziness may occur, especially if blood pressure is severely high
  • Heart failure: Sudden weight gain, shortness of breath, swelling in your lower legs and feet, and fatigue
  • Kidney failure: Fatigue, producing less urine than usual, swelling in your hands, feet, arms, or legs
  • Anemia (low red blood cell count): Tiredness, feeling cold all the time, or looking more pale than usual
  • Serious skin reactions: Skin rash, peeling, redness, discoloration, irritation, or swelling
  • Severe allergic reaction: Hives, trouble breathing, swelling of the face, tongue, or throat, indicating a life-threatening reaction

Long-Term Side Effects

Ponstel treatment can raise the risk of serious heart problems, such as blood clots, heart attack, and stroke. The longer you take the medication, the higher your risk. Additionally, long-term use of NSAIDs, including mefenamic acid, may cause high blood pressure. 

Healthcare providers typically only prescribe Ponstel for short-term use, which usually is for up to one week. 

Report Side Effects

Ponstel may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Ponstel Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (capsules):
    • For menstrual cramps:
      • Adults and children 14 years of age and older—At first, 500 milligrams (mg), then 250 mg every 6 hours as needed, for 2 to 3 days.
      • Children younger than 14 years of age—Use and dose must be determined by your doctor.
    • For mild to moderate pain:
      • Adults and children 14 years of age and older—At first, 500 milligrams (mg), then 250 mg every 6 hours as needed, for not more than 1 week.
      • Children younger than 14 years of age—Use and dose must be determined by your doctor.

Modifications

Ponstel capsules are meant to be swallowed whole. The drug’s manufacturer has not provided guidance on whether it is OK to open the capsules. If you have trouble swallowing this medication, ask your healthcare provider for advice.

Missed Dose

If you miss a dose of Ponstel, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose. Do not take two doses at once unless your provider specifically advises it.

Overdose: What Happens If I Take Too Much Ponstel?

Symptoms of an overdose of Ponstel may include:

  • Drowsiness
  • Feeling lethargic (sluggish)
  • Nausea
  • Vomiting
  • Abdominal pain
  • GI bleeding

Rarely, an NSAID overdose may cause high blood pressure, kidney failure, slow breathing, or coma. Seek medical attention if you or someone else has taken too much.

What Happens If I Overdose on Ponstel?

If you think you or someone else may have overdosed on Ponstel, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Ponstel, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits. to make sure this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

This medicine may raise your risk of having a heart attack or stroke. This is more likely in people who already have heart disease or in people who use this medicine for a long time. Check with your doctor right away if you are having chest pain or discomfort, nausea or vomiting, pain or discomfort in the arms, jaw, back, or neck, trouble breathing, slurred speech, or weakness.

This medicine may cause bleeding in your stomach or intestines. These problems can happen without warning signs. This is more likely if you have had a stomach ulcer in the past, if you smoke or drink alcohol regularly, are over 60 years of age, are in poor health, or using certain other medicines (eg, steroid medicine, blood thinner).

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.

Serious skin reactions, including exfoliative dermatitis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms (DRESS) can occur with this medicine. Check with your doctor right away if you have black, tarry stools, blistering, peeling, or loosening of the skin, chest pain, chills, cough, diarrhea, fever, itching, joint or muscle pain, painful or difficult urination, red irritated eyes, red skin lesions, sore throat, sores, ulcers, or white spots in the mouth or on the lips, swollen glands, unusual bleeding or bruising, or unusual tiredness or weakness.

Some possible warning signs of some serious side effects that can occur during treatment with this medicine may include swelling of the face, fingers, feet, or lower legs, severe stomach pain, black, tarry stools, or vomiting of blood or material that looks like coffee grounds, unusual weight gain, yellow skin or eyes, decreased urination, bleeding or bruising, or skin rash. Also, signs of serious heart problems could occur including chest pain or tightness, fast or irregular heartbeat, unusual flushing or warmth of skin, weakness, or slurring of speech. Check with your doctor immediately if you notice any of these warning signs.

Check with your doctor right away if you have bloody urine, a decrease in frequency or amount of urine, an increase in blood pressure, increased thirst, loss of appetite, lower back or side pain, nausea, swelling of the face, fingers, or lower legs, trouble breathing, unusual tiredness or weakness, vomiting, or weight gain. These could be symptoms of a serious kidney problem.

Hyperkalemia (high potassium in the blood) may occur while you are using this medicine. Check with your doctor right away if you have stomach pain, confusion, difficulty with breathing, irregular heartbeat, nausea or vomiting, nervousness, numbness or tingling in the hands, feet, or lips, or weakness or heaviness of the legs.

This medicine may cause a serious allergic reaction called anaphylaxis, which can be life-threatening and requires immediate medical attention. Tell your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after using this medicine.

This medicine may cause a delay in ovulation for women and may affect their ability to have children. If you plan to have children, talk with your doctor before using this medicine.

Using this medicine during the later part of a pregnancy can harm your unborn baby. If you think you have become pregnant while using this medicine, tell your doctor right away.

Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Ponstel?

Mefenamic acid is not safe for everyone. This medication should not be taken if:

  • You have had an allergic reaction to mefenamic acid or any of its ingredients in the past.
  • You’ve developed hives, asthma, or another type of reaction after taking aspirin or another NSAID in the past. Some people who’ve had reactions to one type of NSAID also have reactions to other NSAIDs.
  • You recently had a heart surgery called coronary artery bypass graft (CABG) or if you’re having this procedure soon. Taking Ponstel around the type of CABG surgery may increase the risk of serious side effects that may be life-threatening.
  • You have preexisting kidney disease.
  • You have acute active ulceration or chronic inflammation of the gastrointestinal tract.
  • You are in late-trimester pregnancy due to the risk of premature closure of the ductus arteriosus (a rare heart condition in premature infants in which there is a continued opening between the two major blood vessels of the heart). If you are pregnant, discuss with your healthcare provider the risk Ponstel may pose to you or your fetus.

What Other Medications Interact With Ponstel?

Mefenamic acid interacts with several other medications. The lists below do not include all of the possible interactions. Before taking this medication, tell your healthcare provider about all of your current medications, including prescriptions, over-the-counter (OTC) medicines, vitamins, herbs, and supplements.

Some examples of drugs that may interact with mefenamic acid are summarized below.

The following drugs may increase the risk of gastrointestinal side effects if taken with mefenamic acid:

Mefenamic acid may affect how well some other medications work, or it may increase the side effects of certain other medications. Examples include:

What Medications Are Similar?

Ponstel belongs to a class of drugs called NSAIDs. Other NSAIDs are available, some with a prescription and some over the counter. Examples include:

NSAIDs differ in their potency and dosing, and individual results can vary with different drugs in this class. If one NSAID doesn’t work well for you or causes side effects, your healthcare provider may switch you to a different NSAID.

In most cases, people should not take more than one NSAID at a time. Consult your healthcare provider before taking another NSAID while taking mefenamic acid.

Frequently Asked Questions

  • How does Ponstel work?

    Like other NSAIDs, this medication is thought to work by decreasing the body’s prostaglandin production. Prostaglandins are a group of hormone-like lipids (fats) that your body makes at sites of injury or infection. They play a key role in causing an inflammatory response.

  • What OTC drugs should not be taken with Ponstel?

    Ponstel belongs to a class of drugs called NSAIDs. You should not take other NSAIDs while you’re taking Ponstel. This includes prescription and OTC NSAIDs. Because many OTC pain relievers and cold medicines also contain NSAIDs, be sure to read labels and avoid products that contain NSAID ingredients such as aspirin, ibuprofen, and naproxen. You can ask your healthcare provider or pharmacist if you're unsure as to what you shouldn't take.

  • Should mefenamic acid be taken with food?

    Yes. Healthcare providers typically recommend that you take each dose of Ponstel with food. Doing so helps to prevent or lessen stomach-related side effects.

How Can I Stay Healthy While Taking Ponstel?

Besides taking medication, consider trying other strategies to relieve pain, such as applying a heating pad or cold compress to the painful area.

When your healthcare provider prescribes a new medication like Ponstel, it’s common to feel worried about side effects. The good news is that most people do not experience serious side effects from this medication.

Some people have mild side effects, but severe side effects are rare when taken in the prescribed dose for a short period. However, if you think you are having a serious side effect, seek medical care right away. 

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Mefenamic acid label.

  2. Guzman-Esquivel J, Galvan-Salazar HR, Guzman-Solorzano HP, et al. Efficacy of the use of mefenamic acid combined with standard medical care vs. standard medical care alone for the treatment of COVID‑19: A randomized double‑blind placebo‑controlled trial. Int J Mol Med. 2022;49(3):29. doi:10.3892/ijmm.2022.5084

  3. Moore N, Pollack C, Butkerait P. Adverse drug reactions and drug-drug interactions with over-the-counter NSAIDs. Ther Clin Risk Manag. 2015;11:1061-75. doi:10.2147/TCRM.S79135

  4. Prescribers' Digital Reference. Mefenamic acid - drug summary.

  5. Kawazoe H, Yano A, Ishida Y, et al. Non-steroidal anti-inflammatory drugs induce severe hematologic toxicities in lung cancer patients receiving pemetrexed plus carboplatin: a retrospective cohort study. PLoS One. 2017;12(2):e0171066. doi:10.1371/journal.pone.0171066

  6. Ricciotti E, FitzGerald GA. Prostaglandins and inflammation. Arterioscler Thromb Vasc Biol. 2011;31(5):986-1000. doi:10.1161/ATVBAHA.110.207449

By Patricia Weiser, PharmD
Patricia Weiser, PharmD, is a licensed pharmacist and freelance medical writer. She has more than 14 years of professional experience.