mefenamic acid


EL Lab


Full Prescribing Info
Mefenamic acid.
Pharmacology: Mefenamic Acid (ISTAN) belongs to a family of aspirin-like drugs that are derivatives of N-phenylanthranilic acid. It has analgesic as well as anti-inflammatory and antipyretic activities. As an analgesic, it displays both central and peripheral actions.
Pharmacokinetics: Absorption and Fate: Mefenamic Acid (ISTAN) is absorbed from the gastro-intestinal tract. Peak plasma concentrations occur about 2-4 hours after ingestion. The half life is reported to be 2-4 hours. Mefenamic Acid is extensively bound to plasma proteins. Over 50% of a dose may be recovered in the urine, as unchanged drug or conjugated metabolites.
Pregnancy and Neonate: Mefenamic acid given to nursing mothers was found in the breast milk in very small quantities.
Mefenamic Acid (ISTAN) relieves postoperative, post extraction and postpartum pains; headache, dysmenorrhea, dental pain, traumatic pain and other painful musculoskeletal conditions such as osteoarthritis and rheumatoid arthritis, including pain and fever following inflammatory conditions.
Dosage/Direction for Use
To be taken with food.
Adults: 500 mg initially, then 250 mg every 6-8 hours.
Children: 25mg/kg body weight per day in divided doses.
Some authorities suggest that treatment with mefenamic acid should not be continued for longer than 7 days.
Mefenamic Acid (ISTAN) is contraindicated to patients showing evidence of gastro-intestinal ulceration and hypersensitivity to Mefenamic Acid.
Special Precautions
Mefenamic Acid (ISTAN) is not recommended for use in pregnant women, and those with renal or hepatic impairment particularly in the elderly. It should not be administered with coumarin anticoagulants.
It should be given with care to the elderly, to patients with asthma or bronchospasm, bleeding disorders, cardiovascular disease, a history of peptic ulceration, and in liver or renal failure. Patients with congestive heart failure, cirrhosis, diuretic-induced volume depletion or renal insufficiency require local synthesis of vasodilating prostaglandins to maintain renal perfusion and therefore these patients are at greater risk of developing renal dysfunction due to NSAID induced inhibition of renal prostaglandin synthesis.
Adverse Reactions
The most common adverse effects occurring with Mefenamic Acid are gastro-intestinal disturbances including diarrhea, nausea, vomiting, and abdominal pain. Peptic ulceration and gastro-intestinal bleeding have also been reported. Headache, drowsiness, dizziness, nervousness, and visual disturbances have been reported. There may be hypersensitivity reactions including skin rashes and urticaria, and occasionally allergic glomerulonephritis; asthma may be precipitated. Reported hematological effects include hemolytic anemia, agranulocytosis, pancytopenia, thrombocytopenia or thrombocytopenic purpura, and bone-marrow aplasia. Renal failure, glomerulonephritis and papillary necrosis have been reported. Therapy should be discontinued if diarrhea or skin rash occur.
Store at temperature not exceeding 30°C.
ATC Classification
M01AG01 - mefenamic acid ; Belongs to the class of non-steroidal antiinflammatory and antirheumatic products, fenamates.
Cap 500 mg (blue or white hard gelatin) x 100's.
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