Mefenamic%252525252525252525252525252520acid

# Mefenamic Acid ## Overview Mefenamic acid is an anthranilic acid derivative nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis. It possesses analgesic, anti-inflammatory, and antipyretic properties. ## Primary Indications * Treatment of mild to moderate pain. * Treatment of primary dysmenorrhea. * *Note: Duration of therapy is typically limited to ≤7 days due to toxicity risks.* ## Adult Dosing * **Pain/Dysmenorrhea:** 500 mg orally as an initial dose, followed by 250 mg every 6 hours as needed. * **Maximum Dose:** Do not exceed 1,500 mg/day. ## Pediatric Dosing * **Children ≥14 years:** Use adult dosing schedule. * **Children <14 years:** Safety and efficacy have not been established. Clinical use in this population is generally not recommended. ## Dose Adjustments * **Renal Impairment:** Contraindicated in patients with severe renal impairment (CrCl <30 mL/min). Use with caution in mild-to-moderate impairment; monitor renal function closely. * **Hepatic Impairment:** Use with caution. Consider lower doses as the drug is extensively metabolized by the liver. ## Contraindications * Known hypersensitivity (including aspirin or other NSAIDs). * History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs. * Peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery. * History of GI bleeding or active peptic ulcer disease. * Severe heart failure or severe renal/hepatic impairment. ## Adverse Effects * **GI:** Abdominal pain, dyspepsia, nausea, diarrhea (frequent), GI ulcers, or hemorrhage. * **CV:** Increased risk of serious cardiovascular thrombotic events (myocardial infarction, stroke). * **Renal/Hepatic:** Elevated liver enzymes, renal insufficiency, fluid retention, edema. * **Hematologic:** Anemia, blood dyscrasias. * **CNS:** Dizziness, headache, nervousness. ## Key Drug Interactions * **Anticoagulants (e.g., Warfarin):** Increased risk of bleeding. * **Antiplatelet agents/SSRIs:** Increased risk of GI bleeding. * **Antihypertensives (ACE inhibitors, ARBs, Diuretics):** May attenuate antihypertensive efficacy; increased risk of nephrotoxicity. * **Lithium/Methotrexate:** Decreased renal clearance, increasing risk of toxicity. * **Corticosteroids:** Increased risk of GI ulceration or hemorrhage. ## Monitoring * Baseline and periodic monitoring of CBC, LFTs, and serum creatinine/BUN. * Monitor blood pressure periodically. * Assess for occult GI bleeding or signs of cardiovascular/thromboembolic events. ## Clinical Pearls * **Duration Limit:** Due to the risk of significant GI toxicity and blood dyscrasias, treatment duration should not exceed 7 days. * **Administration:** Take with food or milk to minimize gastrointestinal irritation. * **GI Protection:** In high-risk patients, consider concurrent proton pump inhibitor (PPI) therapy, though benefit must be weighed against NSAID risks. * **Pregnancy:** Avoid in late pregnancy (third trimester) due to risk of premature closure of the ductus arteriosus. *** *Disclaimer: This information is for educational purposes only. Clinical protocols and local prescribing guidelines vary. Always verify specific dosing, safety warnings, and contraindications via current institutional guidelines or official product labeling (FDA/EMA) before prescribing or administering medication.*