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# Mefenamic acid (Meftal-P)
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) that exhibits analgesic, anti-inflammatory, and antipyretic properties by inhibiting cyclooxygenase (COX-1 and COX-2) enzymes, thereby reducing prostaglandin synthesis.
## Primary Indications
* Acute pain management (short-term use, typically ≤7 days).
* Primary dysmenorrhea.
* *Note: "Meftal-P" specifically is often marketed as a pediatric suspension for fever and pain, though mefenamic acid is generally not the first-line NSAID for pediatrics.*
## Adult Dosing
* **Standard dose:** 500 mg orally initially, followed by 250 mg every 6 hours as needed.
* **Maximum duration:** Do not exceed 1 week of therapy.
## Pediatric Dosing
* **General guidance:** Typically 2–4 mg/kg per dose, administered 3 to 4 times daily.
* **Max dose:** Do not exceed 25 mg/kg/day.
* **Age restriction:** Generally contraindicated in children under 6 months; use caution and clinical judgment for use in children under 14 years. Follow local institutional protocols for specific pediatric dosing weight-based tables.
## Dose Adjustments
* **Renal Impairment:** Avoid in patients with severe renal impairment (CrCl <30 mL/min). Use with caution in mild-to-moderate impairment; monitor renal function.
* **Hepatic Impairment:** Avoid in severe hepatic impairment. Reduce dose if necessary and monitor liver function enzymes.
## Contraindications
* Known hypersensitivity to mefenamic acid, aspirin, or other NSAIDs.
* Active peptic ulceration or inflammatory bowel disease.
* History of GI bleeding or perforation related to previous NSAID therapy.
* Perioperative use in the setting of coronary artery bypass graft (CABG) surgery.
* Severe heart failure.
* Third trimester of pregnancy (risk of premature closure of the ductus arteriosus).
## Adverse Effects
* **Common:** Abdominal pain, nausea, diarrhea, dyspepsia, dizziness, and headache.
* **Serious:** Gastrointestinal ulceration/bleeding, cardiovascular thrombotic events, fluid retention, renal impairment, and severe skin reactions (e.g., Stevens-Johnson syndrome).
## Key Drug Interactions
* **Anticoagulants (e.g., Warfarin):** Increased risk of bleeding.
* **SSRIs/SNRIs:** Increased risk of gastrointestinal bleeding.
* **Anti-hypertensives:** Potential attenuation of the antihypertensive effect of ACE inhibitors, ARBs, and diuretics.
* **Lithium/Methotrexate:** NSAIDs may decrease clearance, increasing risk of systemic toxicity.
* **Other NSAIDs:** Concurrent use increases risk of adverse effects without significant therapeutic benefit.
## Monitoring
* **GI:** Monitor for signs of gastrointestinal bleeding (melena, hematemesis).
* **Renal/Hepatic:** Periodic monitoring of serum creatinine, BUN, and liver enzymes in long-term or high-risk patients.
* **Cardiovascular:** Monitor blood pressure and observe for signs of fluid retention/edema.
## Clinical Pearls
* Take with food or milk to minimize gastrointestinal irritation.
* Use the lowest effective dose for the shortest duration necessary to control symptoms.
* Mefenamic acid is not considered a first-line NSAID for children due to a broader safety profile of alternatives like ibuprofen or acetaminophen.
* Discontinue use immediately if skin rash or symptoms of hypersensitivity occur.
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**Disclaimer:** This information is for educational purposes only. Always consult the latest local prescribing information, product monographs, or a clinical pharmacist before prescribing or administering medication to verify dosing, contraindications, and drug interactions.
