Mefenamic Acid

Indication

Mefenamic acid is indicated in mild to moderate pain including headache, migraine, dental pain, postoperative and postpartum pain and primary dysmenorrhea; in musculoskeletal and joint disorders such as osteoarthritis and rheumatoid arthritis and in menorrhagia.

Dosage and Administration

Carefully consider the potential benefits and risks and other treatment options before deciding to use mefenamic acid. Use the lowest effective dose for the shortest duration and should be taken preferably with meal.

For the relief of acute pain in adults and adolescents 14 years of age, 500 mg initial dose followed by 250 mg every 6 hrs as needed, usually not to exceed one week. For the treatment of primary dysmenorrhea,500 mg initial dose followed by 250 mg every 6 hrs, not to exceed more than 2-3 days.

Do not take more than 7 days unless recommended by physician.

Do not give this medicine to children younger than 14 years old.

Composition

Each caplet contains:

Mefenamic Acid B.P ... 500 mg.

Description

Mefenamic acid is a member of the fenamate group of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs). It is an inhibitor of cyclo-oxygenase. Chemically, it is 2-(2,3-Dimethylanilino) benzoic acid. The empirical formula of mefenamic acid is C15H15NO2 and molecular weight of mefenamic acid is 241.3.

Clinical Pharmacology

Like other NSAIDs, mefenamic acid has anti-inflammatory, analgesic and antipyretic actions by inhibiting prostaglandin synthesis. Mefenamic acid is non­-selective cyclo-oxygenase enzyme inhibitor and inhibits COX-I and COX-2. Cyclo-oxygenase is an enzyme that catalyzes the formation of prostaglandin...read more

Pharmacokinetics

Mefenamic acid is absorbed from the gastrointestinal tract. Peak plasma concentration occurs about 2-4 hours after ingestion. The plasma elimination half-life is 2-4 hours. Mefenamic acid is extensively bound to plasma proteins. It can be distributed into breast milk. Mefenamic acid is metabolized b...read more

Contraindication

It is contraindicated in patient with known hypersensitivity to mefenamic acid with any ingredients in the formulation, aspirin or any other NSAIDs; acute active ulceration or chronic inflammation of upper or lower gastrointestinal tract; in treatment of peri-operative pain in the setting of coronar...read more

Precaution

Anaemia, Thrombocytopenia, pre-existing asthma, diarrhea and rash, drowsiness, colitis, peptic ulcer, renal failure in elderly patients, pancreatitis, cardiovascular defects, breast-feeding.

Adverse Effect

Gastrointestinal: nausea, vomiting, diarrhea, GI ulceration, GI bleeding, dyspepsia, constipation.

Central Nervous System: headache, dizziness, drowsiness, msomma.

Haematologic: occasionally thrombocytopenia, chronic heart failure, tachycardia, aplastic, anaemia, haemolytic anaemia, agranulocytosis, hypertension.

Other undesirable effects: bronchospasm, visual disturbances, tinnitus, urticaria, rash, glucose intolerance, abnormal renal function.

Hepatic: Elevated liver function test.

Drug Interaction

Cytochrome P450 effect: Substrate of CYP2C8/9, inhibits CYP2C8/9.

Increased Effect/ toxicity: Anticoagulants (warfarin, heparin) or other antiplatelet drugs (ticlopidine, clopidogrel, aspirin, abciximab) in combination with NSAIDs can cause increased risk of bleeding.

NSAIDs may increase serum creatinine, potassium, blood pressure and cyclosporine levels during concurrent therapy; monitor cyclosporine levels and renal function carefully. Lithium levels can be increased; avoid concurrent use if possible or monitor lithium levels and adjust dose. Corticosteroids ma...read more

Decreased Effect:

Antihypertensive effects of ACEI, angiotensin antagonists, diuretics and hydralazine may be decreased by concurrent therapy with NSAIDs; monitor blood pressure.

Interaction with Ethanol: Avoid ethanol (due to GI irritation).

Storage

Store below 30°C in cool, dry place. Protect from light and moisture.

Keep out of reach and sight of children.

Presentation

10 x 10's Blisters, 20 x 10's Blisters.