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250 mg: Allergy Alert: Mefenamic acid may cause a severe allergic reaction which may include: Hives (elevated, whitish or reddish patches on the skin with severe itching or pricking sensations); Shock (anaphylactic), a hypersensitivity reaction resulting to generalized skin lesions and itchiness, followed by vascular collapse and often accompanied by life-threatening respiratory distress; Facial swelling; Skin reddening; Asthma (wheezing); Skin rash or skin blisters.
Stomach Bleeding Warning: This product contains an NSAID, which may cause severe stomach bleeding. The chance is higher if the patient: Is age 60 years or older; Have had stomach ulcers or bleeding problems; Take a blood thinning (anticoagulant) or steroid medicine; Take other medicines containing prescription or nonprescription NSAIDs (aspirin, ibuprofen or others); Have 3 or more alcoholic drinks everyday while using this product; Take more or for a longer time than directed.
The risk of heart attack or stroke may increase if the patient use more than or longer than directed.
Mefenamic acid should be used with caution in elderly patients suffering from dehydration and kidney disease.
When to consult a Doctor: Ask a doctor before use if the patient is: Having problems or serious side effects from taking pain relievers or fever reducers.
Taking aspirin or other NSAIDs.
Taking other medicines.
Under a doctor's care for any serious condition.
Trying to become pregnant; NSAIDs may impair fertility in women. This effect is reversible upon stopping the medicine.
Ask a doctor before use if: Stomach bleeding warning applied to the patient.
The patient has heart problems, previous stroke or might be at risk of these conditions (e.g., high blood pressure, high cholesterol, diabetes, or if the patient is a smoker).
The patient has a history of stomach problems, such as heartburn, Crohn's disease (inflammation of the digestive system) or ulcerative colitis (ulcers in the lining of the rectum and colon).
The patient has liver or kidney problems.
The patient has asthma.
The patient is suffers from systemic lupus erythematosus (SLE) or other auto-immune diseases.
Stop use and ask a doctor if: The patient experience any of the following signs of stomach bleeding: Feel faint; Vomit blood; Have bloody or black stools; Have stomach pain that does not get better.
An allergic reaction occurs.
New symptoms occur.
Symptoms do not get better.
Headache is persistent.
If the patient is pregnant or breastfeeding, ask a doctor before use. It is especially important not to use mefenamic acid during the last three months of pregnancy unless definitely directed to do so by a doctor because it may cause problems in the unborn child or complications during delivery.
500 mg: General: Frail or debilitated patients may tolerate side effects less well and therefore special care should be taken in treating this population. As with other NSAIDs, caution should be used in the treatment of elderly patients who are more likely to be suffering from impaired renal, hepatic or cardiac function. For high risk patients, alternate therapies that do not involve NSAIDs should be considered.
Mefenamic acid is NOT recommended for use with other NSAIDs, with the exception of low-dose aspirin for cardiovascular prophylaxis, because of the absence of any evidence demonstrating synergistic benefits and the potential for additive adverse reactions (see Interactions).
Cardiovascular Effects (see Warnings): Cardiovascular Thrombotic Events: Clinical trials using COX-2 selective and nonselective NSAIDs of up to three years duration have shown an increased risk of serious cardiovascular thrombotic events, myocardial infarction and stroke, which can be fatal. Patients with known cardiovascular disease or risk factors for cardiovascular disease may be at greater risk. To minimize the potential risk for an adverse cardiovascular event in patients treated with an NSAID, the lowest effective dose should be used for the shortest duration possible. Physicians and patients should be alert for the development of such events, even in the absence of previous cardiovascular symptoms. Patients should be informed on the signs and/or symptoms of serious cardiovascular events and the steps to take if they occur.
As NSAIDs can interfere with platelet function, they should be used with caution in patients with intracranial hemorrhage and bleeding diathesis.
There is no consistent evidence that concurrent use of aspirin mitigates the increased risk of serious cardiovascular thrombotic events associated with NSAID use. The concurrent use of aspirin and an NSAID does increase the risk of serious GI events.
Hypertension: NSAIDs, including mefenamic acid, can lead to the onset of new hypertension or worsening of preexisting hypertension, either of which may contribute to the increased incidence of cardiovascular events. Patients taking thiazides or loop diuretics may have impaired response to these therapies when taking NSAIDs. NSAIDs, including mefenamic acid, should be used with caution in patients with hypertension. Blood pressure should be monitored closely during initiation of NSAID treatment and throughout the course of therapy.
Congestive Heart Failure and Edema: Fluid retention and edema have been observed in some patients taking NSAIDs. Mefenamic acid should be used with caution in patients with fluid retention or heart failure.
Endocrine/Metabolic Effects: Mefenamic acid is NOT a substitute for corticosteroids. It does NOT treat corticosteroid insufficiency. Abrupt discontinuation of corticosteroids may lead to exacerbation of corticosteroid-responsive illness. Patients on prolonged corticosteroid therapy should have their therapy tapered slowly if a decision is made to discontinue corticosteroids (see Interactions).
Gastrointestinal Effects (see Warnings): NSAIDs, including mefenamic acid, can cause serious GI adverse events including inflammation, bleeding, ulceration, and perforation of the stomach, small or large intestines, which can be fatal. These serious adverse events can occur at any time, with or without warning symptoms, in patients treated with NSAIDs.
NSAIDs should be prescribed with extreme caution in those with a history of ulcer disease or GI bleeding since these patients have a greater than 10-fold increased risk for developing a GI bleed compared with patients with neither of these risk factors. Other factors that increase the risk for GI bleeding in patients treated with NSAIDs include concomitant use of oral corticosteroids or anticoagulants, longer duration of NSAID therapy, smoking, use of alcohol, older age, and poor general health status. Elderly patients, in particular, are at greater risk for serious GI events.
The lowest effective dose should be used for the shortest possible duration to minimize the potential risk for an adverse GI event. Physicians and patients should remain alert for signs and symptoms of GI ulceration and bleeding during NSAID therapy and promptly initiate additional evaluation and treatment if a serious GI adverse event is suspected. This should include discontinuation of the NSAID until a serious GI adverse event is ruled out. Alternate therapies that do not involve NSAIDs should be considered especially for high-risk patients.
NSAIDs should be given with care in patients with a history of GI disease (ulcerative colitis, Crohn's disease) as these conditions may be exacerbated.
Diarrhea occasionally occurs following the use of mefenamic acid. Although this may occur soon after starting treatment, it may also occur after several months of continuous use.
Genitourinary Effects: Long-term administration of NSAIDs has resulted in renal papillary necrosis and other renal injury. Renal toxicity has also been seen in patients in whom renal prostaglandins have a compensatory role in the maintenance of renal perfusion. In these patients, administration of an NSAID may cause a dose-dependent reduction in prostaglandin formation and secondarily, in renal blood flow, which may precipitate overt renal decompensation. Patients at greatest risk of this reaction are those with impaired renal function, heart failure, liver dysfunction, those taking diuretics and Angiotensin Converting Enzyme (ACE) inhibitors, and the elderly. Discontinuation of NSAID therapy is usually followed by recovery to the pretreatment state.
Caution should be exercised when initiating treatment with mefenamic acid in patients with considerable dehydration.
Advanced Renal Disease: There are no controlled studies on the use of mefenamic acid in patients with advanced renal disease. Therefore, treatment with mefenamic acid is not recommended in these patients.
Anaphylactoid Reactions (see Contraindications): Anaphylactoid reactions may occur in patients without known prior exposure to NSAIDs. Mefenamic acid should not be given to patients with the aspirin triad. This symptom complex typically occurs in asthmatic patients who experience rhinitis with or without nasal polyps, or who exhibit severe, potentially fatal bronchospasm after taking aspirin or other NSAIDs. Mefenamic acid should be administered with caution to patients with preexisting asthma and emergency help should be sought in cases where an anaphylactoid reaction occurs.
Skin Reactions: Mefenamic acid can cause serious skin adverse events such as exfoliative dermatitis, Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. These serious events may occur without warning. Patients should be informed about the signs and symptoms of serious skin manifestations and use of the drug should be discontinued at the first appearance of skin rash or any other sign of hypersensitivity.
Hepatic Effects: Borderline elevations of one or more liver tests may occur in up to 15% of patients taking NSAIDs, including mefenamic acid. These laboratory abnormalities may progress, may remain unchanged or may be transient with continuing therapy. Notable elevations of alanine aminotransferase (ALT) or aspartate aminotransferase (AST) (approximately three or more times the upper limit of normal) have been reported in approximately 1% of patients in clinical trials with NSAIDs. Rare cases of severe hepatic reactions, including jaundice and fatal fulminant hepatitis, liver necrosis, and hepatic failure, some with fatal outcomes have been reported.
Patients with symptoms and/or signs suggesting liver dysfunction, or in whom an abnormal liver test has occurred, should be evaluated for evidence of the development of a more severe hepatic reaction while on therapy with NSAIDs. Discontinue mefenamic acid if clinical signs and symptoms consistent with liver disease develop or if systemic manifestations occur (e.g., eosinophilia, rash).
Hematologic Effects: Anemia is sometimes seen in patients receiving NSAIDs including mefenamic acid. Patients on long-term treatment with NSAIDs, including mefenamic acid, should have their hemoglobin or hematocrit checked if they exhibit any signs or symptoms of anemia or blood loss. Mefenamic acid does not generally affect platelet counts, prothrombin time (PT), or partial thromboplastin time (PTT), and does not inhibit platelet aggregation at indicated dosages.
Nervous System Effects: Headache: Prolonged use of any type of analgesic for headaches can make them worse. Medication-overuse headache should not be treated by increasing the dose. In such cases, the use of analgesics should be discontinued and the physician should be consulted.
Aseptic Meningitis: In patients with systemic lupus erythematosus (SLE) and mixed connective tissue disorders, there may be an increased risk of aseptic meningitis.
Epilepsy: Caution should be exercised when treating patients suffering from epilepsy.
Prolonged Use: Patients on prolonged therapy should be kept under regular surveillance with particular attention to liver dysfunction, rash, blood dyscrasias or development of diarrhea.
Effects on the Ability to Drive and Use Machine: Undesirable effects such as dizziness, drowsiness, fatigue and visual disturbances are possible after taking NSAIDs. If afflicted, patients should not drive or operate machinery.
Use in Children (<14 years old): The safety and efficacy in pediatric patients below 14 years old have not been established.
Use in the Elderly (≥65 years old): Elderly and frail or debilitated patients are more susceptible to a variety of adverse reactions from NSAIDs; the incidence of these adverse reactions increases with dose and duration of treatment. In addition, these patients are less tolerant to ulceration and bleeding. Most reports of fatal GI events are in this population.
Older patients are also at risk of lower esophageal injury including ulceration and bleeding.
For such patients, consideration should be given to a starting dose lower than the one usually recommended, with individual adjustment when necessary and under close supervision.
