Mefanic%25252525252525252520acid

# Mefenamic Acid ## Overview Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) of the fenamate class. It possesses analgesic, anti-inflammatory, and antipyretic properties, primarily by inhibiting cyclooxygenase (COX-1 and COX-2) enzymes. ## Primary Indications * Treatment of primary dysmenorrhea. * Short-term management of mild-to-moderate pain (use limited to ≤7 days). ## Adult Dosing * **Dysmenorrhea/Pain:** 500 mg initially, followed by 250 mg every 6 hours as needed. * **Maximum:** Not to exceed 1 week of therapy. ## Pediatric Dosing * **Children ≥14 years:** Follow adult dosing (500 mg initially, then 250 mg every 6 hours). * **Children <14 years:** Safety and efficacy have not been established. ## Dose Adjustments * **Renal Impairment:** Avoid or use with extreme caution in patients with severe renal impairment (CrCl <30 mL/min). * **Hepatic Impairment:** Use caution; monitor liver enzymes. Dose reduction may be required. * **Geriatric:** Use the lowest effective dose for the shortest duration due to increased risk of cardiovascular and gastrointestinal toxicities. ## Contraindications * Known hypersensitivity to mefenamic acid, aspirin, or other NSAIDs (risk of bronchospasm/anaphylaxis). * History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs. * Pre-operative pain management in the setting of coronary artery bypass graft (CABG) surgery. * Active gastrointestinal (GI) ulceration or inflammatory bowel disease. ## Adverse Effects * **Gastrointestinal:** Diarrhea (common and dose-dependent), nausea, dyspepsia, abdominal pain, GI ulceration, or bleeding. * **Cardiovascular:** Edema, hypertension, increased risk of myocardial infarction or stroke. * **Renal:** Acute renal failure, fluid retention. * **Hematologic:** Anemia (potential for blood loss), rare autoimmune hemolytic anemia with long-term use. ## Key Drug Interactions * **Anticoagulants (e.g., Warfarin):** Increased risk of bleeding. * **Antiplatelet agents/SSRIs:** Increased risk of GI bleeding. * **ACE Inhibitors/ARBs/Diuretics:** Reduced antihypertensive effect and increased risk of renal impairment (nephrotoxicity). * **Lithium/Methotrexate:** Potential for increased serum concentrations and toxicity. ## Monitoring * **Baseline:** Monitor CBC, renal function (SCr/BUN), and hepatic function (LFTs) if used long-term or in high-risk patients. * **Ongoing:** Monitor for signs/symptoms of GI bleeding, changes in blood pressure, edema, or allergic reactions. ## Clinical Pearls * **Diarrhea:** Mefenamic acid is uniquely associated with clinical diarrhea; discontinue if severe diarrhea occurs. * **Duration:** Always limit prescription to the shortest duration possible, generally not exceeding 7 consecutive days. * **NSAID Class Effect:** Like all NSAIDs, it carries a boxed warning regarding serious cardiovascular thrombotic events and serious gastrointestinal adverse events. * **Administration:** Take with food or milk to minimize potential GI upset. *** *Disclaimer: This information is for educational purposes and does not replace professional clinical judgment. Always verify current prescribing information, institutional protocols, and patient-specific factors via reliable clinical databases (e.g., Lexicomp, UpToDate) before prescribing or administering medication.*