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Mefenamic Acid

    DEA Class; Rx

    Common Brand Names; Ponstel


    Anthranilic acid (fenamate) NSAID; may cause an increased risk of serious gastrointestinal and cardiovascular adverse events; use lowest effective dose for the shortest possible duration.

    For the treatment of dysmenorrhea.
    For the treatment of mild pain and moderate pain.

    Hypersensitivity, ASA allergy, history of aspirin triad, GI tract ulcer/inflammation, CABG, renal dz, late pregnancy (may cause premature closure of ductus arteriosus)


    Borderline elevations of one or more LFTs (<15%)


    Abdominal pain









    Upper GI ulcers, gross bleeding/perforation (1% of patients treated for 3-6 mth and 2-4% of those treated for 1 yo)

    Use caution in anemia, bronchospasm, cardiac disease, CHF, HTN, SLE, fluid retention, hepatic/renal impairment, bleeding diathesis

    If severe diarrhea occurs, reduce dose or temporarily discontinue drug

    Therapy may cause premature closure of ductus arteriosus; avoid use in pregnant women starting at 30 weeks of gestation (third trimester)

    Mefenamic acid cannot be expected to substitute for corticosteroids or to treat corticosteroid insufficiency; abrupt discontinuation of corticosteroids may lead to disease exacerbation; patients on prolonged corticosteroid therapy should have therapy tapered slowly if a decision is made to discontinue corticosteroid

    Drug associated with anaphylactic reactions in patients with and without known hypersensitivity to mefenamic acid and in patients with aspirin-sensitive asthma

    Therapy can lead to new onset of hypertension or worsening of pre­existing hypertension, either of which may contribute to increased incidence of CV events; patients taking angiotensin-converting enzyme (ACE) inhibitors, thiazides diuretics, or loop diuretics may have impaired response to these therapies when taking this medication; monitor blood pressure during initiation of treatment and throughout course of therapy

    Increases in serum potassium concentration, including hyperkalemia, reported with use, even in some patients without renal impairment; in patients with normal renal function, these effects have been attributed to a hyporeninemic-hypoaldosteronism state


    Use of NSAIDs can cause premature closure of fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment

    Because of these risks, limit dose and duration to between about 20 and 30 weeks of gestation, and avoid use at about 30 weeks of gestation and later in pregnancy


    Trace amounts of mefenamic acid may be present in breast milk and transmitted to nursing infant; because of potential for serious adverse reactions in nursing infants from mefenamic acid, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account importance of drug to mother


    1,250 mg/day PO.


    1,250 mg/day PO.


    14 to 17 years: 1,250 mg/day PO.
    13 years: Safety and efficacy have not been established.


    Safety and efficacy have not been established.


    Safety and efficacy have not been established.


    Safety and efficacy have not been established.


    • 250mg