Please check your internet connection and try again.
# Meftal (Mefenamic Acid)
## Overview
Mefenamic acid is an anthranilic acid derivative nonsteroidal anti-inflammatory drug (NSAID). It exerts analgesic, anti-inflammatory, and antipyretic effects by inhibiting cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin synthesis.
## Primary Indications
* Treatment of primary dysmenorrhea.
* Short-term management of mild to moderate pain (usually not indicated for chronic arthritis).
## Adult Dosing
* **Standard Dose:** 500 mg initially, followed by 250 mg every 6 hours as needed.
* **Maximum Duration:** Should not exceed 1 week of therapy.
## Pediatric Dosing
* **Adolescents (≥14 years):** Same as adult dosing (500 mg initial, then 250 mg every 6 hours).
* **Children (<14 years):** Safety and efficacy have not been established. Use is generally not recommended in this population.
## 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 closely.
* **Hepatic Impairment:** Use with caution; dose reduction may be required. Avoid in severe hepatic disease.
## Contraindications
* Known hypersensitivity to mefenamic acid, aspirin, or other NSAIDs.
* History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
* Perioperative pain in the setting of coronary artery bypass grafting (CABG) surgery.
* Active peptic ulceration or inflammatory bowel disease.
* Severe renal or hepatic impairment.
## Adverse Effects
* **Gastrointestinal:** Nausea, vomiting, diarrhea (often dose-dependent, may be severe), abdominal pain, GI ulceration/bleeding.
* **Renal:** Fluid retention, edema, acute renal failure, interstitial nephritis.
* **Cardiovascular:** Hypertension, increased risk of thrombotic events (MI, stroke).
* **Hematologic:** Anemia, thrombocytopenia, leukopenia.
* **Other:** Dizziness, headache, skin rash.
## Key Drug Interactions
* **Anticoagulants (e.g., Warfarin):** Increased risk of bleeding due to GI irritation and antiplatelet effects.
* **Other NSAIDs/Aspirin:** Additive GI toxicity and systemic side effects; avoid concomitant use.
* **ACE Inhibitors/ARBs/Diuretics:** Reduced antihypertensive effect; increased risk of nephrotoxicity.
* **Lithium/Methotrexate:** Potential for decreased renal clearance leading to toxicity.
## Monitoring
* **Baseline/Intermittent:** CBC, serum creatinine, BUN, and liver function tests (LFTs) during prolonged therapy.
* **Assessment:** Monitor for signs of GI bleeding (occult blood, anemia), edema, or cardiovascular symptoms.
## Clinical Pearls
* **GI Irritation:** Take with food or milk to minimize gastric upset, though this may delay absorption.
* **Duration:** Limit use beyond 7 days due to the increased risk of severe, dose-related diarrhea and intestinal inflammation.
* **CV Warning:** Like all NSAIDs, mefenamic acid carries a boxed warning regarding an increased risk of serious cardiovascular thrombotic events and gastrointestinal events.
* **Diarrhea:** If diarrhea occurs, the dose should be reduced or the drug discontinued immediately.
***
**Disclaimer:** This information is for educational purposes only. Clinical practice protocols may vary by institution. Always verify dosages and contraindications with current labeling, local guidelines, and your institution's formulary before prescribing or administering medication.
