Mefanic%25252525252525252525252525252525252525252525252525252525252525252525252525252525252520acid

# Mefenamic Acid ## Overview Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) belonging to the fenamate class. It exhibits analgesic, anti-inflammatory, and antipyretic properties through the inhibition of cyclooxygenase (COX) enzymes, thereby reducing prostaglandin synthesis. ## Primary Indications * Short-term management of mild to moderate pain. * Symptomatic relief of primary dysmenorrhea. ## Adult Dosing * **Pain:** 500 mg every 6 hours as needed. Maximum of 1500 mg daily for self-medication; up to 3000 mg daily in divided doses under medical supervision, but higher doses are generally not recommended due to increased risk of adverse events. * **Dysmenorrhea:** 500 mg every 6 hours, usually starting with the onset of pain or bleeding and continuing for the duration of symptoms, typically up to 3 days. ## Pediatric Dosing * Mefenamic acid is generally **not recommended for use in children under 14 years of age** due to lack of established safety and efficacy. ## Dose Adjustments * **Renal Impairment:** Use with caution. Consider dose reduction in patients with mild to moderate renal impairment. Avoid in severe renal impairment. * **Hepatic Impairment:** Use with caution. Consider dose reduction in patients with mild to moderate hepatic impairment. Avoid in severe hepatic impairment. * **Elderly:** Increased risk of gastrointestinal bleeding, renal dysfunction, and cardiovascular events. Consider lower doses and closer monitoring. ## Contraindications * Known hypersensitivity to mefenamic acid, aspirin, or other NSAIDs. * History of gastrointestinal bleeding or perforation related to prior NSAID use. * Active or recurrent peptic ulceration or bleeding. * Severe heart failure. * Severe renal impairment. * Severe hepatic impairment. * Third trimester of pregnancy. ## Adverse Effects * **Common:** Diarrhea, nausea, vomiting, abdominal pain, constipation, dyspepsia, dizziness, headache, rash. * **Serious:** Gastrointestinal bleeding, perforation, ulceration; cardiovascular thrombotic events (myocardial infarction, stroke); renal papillary necrosis and other renal injury; hepatic failure; anaphylactoid reactions; exacerbation of asthma; Stevens-Johnson syndrome/toxic epidermal necrolysis. ## Key Drug Interactions * **Anticoagulants (e.g., warfarin):** Increased risk of bleeding. * **Corticosteroids:** Increased risk of gastrointestinal ulceration and bleeding. * **Selective Serotonin Reuptake Inhibitors (SSRIs):** Increased risk of gastrointestinal bleeding. * **Other NSAIDs (including aspirin):** Increased risk of gastrointestinal adverse effects and potential for synergistic effects leading to bleeding. * **Lithium:** Increased serum lithium levels, risk of toxicity. * **Methotrexate:** Increased risk of methotrexate toxicity. * **Diuretics and Antihypertensives:** NSAIDs can reduce the efficacy of these medications and increase the risk of renal impairment. ## Monitoring * **Gastrointestinal:** Monitor for signs and symptoms of bleeding (e.g., melena, hematemesis, abdominal pain). * **Renal Function:** Assess renal function, especially in patients with pre-existing renal disease or those at risk. * **Hepatic Function:** Monitor liver function tests, particularly with prolonged use or in patients with liver disease. * **Cardiovascular:** Assess for signs of cardiovascular events. * **Blood Pressure:** Monitor blood pressure, especially in patients with hypertension. ## Clinical Pearls * Mefenamic acid is intended for **short-term use only**. * It should be taken with food or milk to minimize gastrointestinal upset. * Due to the risk of gastrointestinal bleeding, use the lowest effective dose for the shortest duration necessary. * Hydration is important to prevent renal adverse effects. * Discontinue use immediately if signs of hypersensitivity or serious adverse events occur. *** *Disclaimer: This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and relevant clinical guidelines for complete details. Dosing may vary based on individual patient factors and local institutional protocols.*