Ponstel® (mefenamic acid) is a member of the fenamate group of nonsteroidal anti- inflammatory drugs (NSAIDs). Each blue-banded, ivory capsule contains 250 mg of mefenamic acid for oral administration. Mefenamic acid is a white to greyish-white, odorless, microcrystalline powder with a melting point of 230°-231°C and water solubility of 0.004% at pH 7.1. The chemical name is N-2,3-xylylanthranilic acid. The molecular weight is 241.29. Its molecular formula is C₁₅H₁₅NO₂ and the structural formula of mefenamic acid is:

Each capsule also contains lactose, NF. The capsule shell and/or band contains citric acid, USP; D&C yellow No. 10; FD&C blue No. 1; FD&C red No. 3; FD&C yellow No. 6; gelatin, NF; glycerol monooleate; silicon dioxide, NF; sodium benzoate, NF; sodium lauryl sulfate, NF; titanium dioxide, USP.

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 your doctor has prescribed this medication because he or she 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.

Tell your doctor immediately if any of these unlikely but serious side effects occur: fainting, persistent/severe headache, hearing changes (e.g., ringing in the ears), fast/pounding heartbeat, mental/mood changes, stomach pain, difficult/painful swallowing, swelling of the ankles/feet/hands, sudden/unexplained weight gain, vision changes.

Stop taking mefenamic acid and tell your doctor immediately if any of these rare but very serious side effects occur: easy bruising/bleeding, signs of infection (e.g., fever, persistent sore throat), unexplained stiff neck, change in the amount/color of urine.

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 immediately: persistent nausea/vomiting, severe stomach/abdominal pain, extreme/unusual tiredness, weakness, dark urine, yellowing eyes/skin.

A very serious allergic reaction to this drug is rare. However, stop taking mefenamic acid and immediately seek medical attention if you notice any of the following symptoms of a serious allergic reaction: rash/blisters, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

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.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: 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: aspirin-sensitive asthma (a history of worsening breathing with runny/stuffy nose after taking aspirin or other NSAIDs, severe kidney disease, recent heart bypass surgery (CABG), active bleeding/sores in stomach/intestines (ulcer, gastrointestinal bleeding).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: asthma, bleeding/clotting problems, blood disorders (e.g., anemia), high blood pressure, a severe loss of body water (dehydration), diabetes, heart disease (e.g., congestive heart failure, history of heart attack), kidney disease, liver disease, growths in the nose (nasal polyps), obesity, tobacco use, history of stomach/intestine/esophagus problems (e.g., bleeding, ulcers, recurring heartburn), stroke, swelling of the ankles/feet/hands.

Before having surgery, tell your doctor or dentist that you are using this medication.

This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages.

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. Avoid prolonged sun exposure, tanning booths, or sunlamps. Use a sunscreen and wear protective clothing when outdoors.

Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, caution is advised when using this drug in the elderly because they may be more sensitive to its side effects, especially stomach bleeding and kidney effects.

During the first 6 months of pregnancy, this medication should be used only when clearly needed. It is not recommended for use during the last 3 months of pregnancy due to possible harm to the unborn baby and interference with normal labor/delivery. Discuss the risks and benefits with your doctor.

This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.