Please check your internet connection and try again.
# Mefenamic acid (Meftal-P)
## Overview
Mefenamic acid is a non-steroidal anti-inflammatory drug (NSAID) of the fenamate class. It possesses analgesic, anti-inflammatory, and antipyretic properties, primarily by inhibiting prostaglandin synthesis via cyclooxygenase (COX-1 and COX-2) inhibition.
## Primary Indications
* Mild to moderate pain (short-term use, typically $\le$ 7 days).
* Primary dysmenorrhea.
* Antipyretic (often used in pediatric populations under specific regional guidelines).
## Adult Dosing
* **Pain/Dysmenorrhea:** 500 mg initially, followed by 250 mg every 6 hours as needed.
* **Maximum Dose:** 1500 mg per day. Duration of therapy should not exceed 7 days.
## Pediatric Dosing
* **Antipyretic (where approved):** 6.5 mg/kg body weight per dose, administered every 6–8 hours.
* **Note:** Not recommended for children under 6 months of age. Use only under medical supervision.
## Dose Adjustments
* **Renal Impairment:** Contraindicated in severe renal impairment. Use with extreme caution and reduced frequency in mild-to-moderate impairment.
* **Hepatic Impairment:** Use with caution; monitor liver function if prolonged use is unavoidable.
* **Elderly:** Risk of gastrointestinal toxicity and renal complications is higher; use the lowest effective dose for the shortest duration.
## Contraindications
* Known hypersensitivity to mefenamic acid or other NSAIDs (including aspirin-induced asthma/urticaria).
* History of GI bleeding or perforation related to prior NSAID therapy.
* Active peptic ulcer disease.
* Severe heart failure.
* Preoperative pain relief in the setting of coronary artery bypass graft (CABG) surgery.
* Severe renal or hepatic impairment.
## Adverse Effects
* **Common:** Nausea, abdominal pain, diarrhea, dyspepsia, headache.
* **Serious:** Gastrointestinal ulceration/bleeding, cardiovascular events (MI, stroke), fluid retention/edema, acute renal failure, interstitial nephritis, and skin reactions (e.g., Stevens-Johnson syndrome).
## Key Drug Interactions
* **Anticoagulants (e.g., Warfarin):** Increased risk of bleeding.
* **Antiplatelets/SSRIs:** Increased risk of gastrointestinal bleeding.
* **Antihypertensives (ACE inhibitors, ARBs, Beta-blockers):** Decreased efficacy; increased risk of renal impairment.
* **Lithium/Methotrexate:** Decreased renal clearance, leading to potential toxicity.
* **Other NSAIDs:** Avoid concurrent use due to additive toxicity.
## Monitoring
* **Renal Function:** Monitor serum creatinine and electrolytes in high-risk patients.
* **Gastrointestinal:** Monitor for signs of occult blood loss or melena.
* **Cardiovascular:** Monitor blood pressure periodically during chronic therapy.
## Clinical Pearls
* **Administration:** Take with food or milk to minimize gastrointestinal irritation.
* **Duration:** Mefenamic acid is intended for short-term use only. Long-term use significantly increases the risk of serious adverse effects.
* **Pediatric Note:** In several jurisdictions, the use of mefenamic acid in children is restricted or discouraged compared to safer alternatives like ibuprofen or acetaminophen. Always verify against local pediatric formulary protocols.
* **Safety Warning:** All NSAIDs carry a "Black Box Warning" regarding an increased risk of serious cardiovascular thrombotic events and serious gastrointestinal adverse events.
***
*Disclaimer: This information is for educational purposes and does not constitute medical advice. Prescribing practices may vary based on institutional protocols and local regulatory guidelines. Always consult the latest package insert and clinical guidelines before prescribing or administering any medication.*
