Meftal (mefenamic Acid)

# Meftal (Mefenamic Acid) ## Overview Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that acts primarily by inhibiting cyclooxygenase (COX-1 and COX-2) enzymes, leading to reduced prostaglandin synthesis. It is typically indicated for short-term management of mild to moderate pain and primary dysmenorrhea. ## Primary Indications * Primary dysmenorrhea. * Mild to moderate pain (short-term use, typically ≤ 7 days). ## Adult Dosing * **Standard Dose:** 500 mg initially, followed by 250 mg every 6 hours as needed. * **Maximum Dose:** Do not exceed 1,500 mg per day. * **Duration:** Limit total treatment duration to 7 days due to the risk of gastrointestinal and renal toxicity. ## Pediatric Dosing * **Children < 14 years:** Safety and efficacy have not been established; use is generally not recommended. * **Adolescents (≥ 14 years):** Follow adult dosing schedule (500 mg initial, then 250 mg every 6 hours). ## Dose Adjustments * **Renal Impairment:** Avoid in patients with severe renal impairment (CrCl < 30 mL/min). Use with extreme caution in mild-to-moderate impairment; close monitoring of renal function is required. * **Hepatic Impairment:** Use with caution; dose reduction may be necessary. Avoid in severe hepatic failure. * **Elderly:** Use the lowest effective dose for the shortest duration possible due to increased risk of GI bleeding and renal complications. ## Contraindications * Known hypersensitivity to mefenamic acid, aspirin, or other NSAIDs. * History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs. * Active peptic ulcer disease or history of GI bleeding/perforation. * Treatment of perioperative pain in the setting of coronary artery bypass graft (CABG) surgery. * Severe heart failure. ## Adverse Effects * **Common:** Abdominal pain, nausea, vomiting, diarrhea, dyspepsia, dizziness, and headache. * **Serious:** GI bleeding, ulceration, perforation, myocardial infarction, stroke, renal failure, interstitial nephritis, fluid retention/edema, and hepatotoxicity. ## Key Drug Interactions * **Anticoagulants (e.g., Warfarin):** Increased risk of bleeding. * **Antiplatelet Agents/SSRIs:** Increased risk of GI bleeding. * **Antihypertensives (ACE inhibitors, ARBs, Diuretics):** Diminished antihypertensive effect; increased risk of renal impairment. * **Lithium/Methotrexate:** Potential for increased serum concentrations and toxicity. * **Other NSAIDs/Corticosteroids:** Increased risk of GI toxicity. ## Monitoring * **Gastrointestinal:** Monitor for signs of bleeding (melena, hematemesis). * **Renal:** Monitor serum creatinine, BUN, and urine output, especially in elderly or comorbid patients. * **Cardiovascular:** Monitor blood pressure; watch for signs of fluid retention. * **Hepatic:** Monitor liver enzymes (ALT/AST) if long-term use is contemplated (though not recommended). ## Clinical Pearls * **Administration:** Take with food or milk to minimize gastrointestinal upset. * **Short-term only:** Mefenamic acid is strictly intended for short-term use. Chronic use increases the risk of serious adverse cardiovascular and gastrointestinal events. * **Diarrhea:** Mefenamic acid is known to cause dose-related diarrhea; if this occurs, the drug should be discontinued. * **Cross-sensitivity:** Patients with a history of aspirin-induced asthma may exhibit cross-sensitivity to mefenamic acid. *** *Disclaimer: This information is for educational purposes and does not replace professional clinical judgment. Always consult the most current local prescribing information, institutional protocols, and official package inserts before administering any medication.*