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# Mefenamic Acid (Meftal-P)
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) used for the short-term treatment of mild to moderate pain. It works by inhibiting cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis.
## Primary Indications
* Short-term management of mild to moderate pain, including:
* Dysmenorrhea
* Headache
* Dental pain
* Musculoskeletal pain
## Adult Dosing
* **Initial dose:** 500 mg orally.
* **Subsequent doses:** 250 mg orally every 6 hours as needed.
* **Maximum duration:** Typically recommended for short-term use, not exceeding 7 days.
* **Maximum daily dose:** 1500 mg.
## Pediatric Dosing
* Mefenamic acid is **not generally recommended** for use in children under 14 years of age due to safety concerns and lack of established dosing guidelines. Some sources suggest 6.5 mg/kg orally every 6 hours for children aged 6 months to 14 years, but this requires careful consideration of risks and benefits and should be guided by local protocol or specialist advice.
## Dose Adjustments
* **Renal Impairment:** Use with caution. Mefenamic acid is renally excreted, and dose adjustments may be necessary. Avoid in severe renal impairment.
* **Hepatic Impairment:** Use with caution. Monitor liver function closely. Avoid in severe hepatic impairment.
* **Elderly:** Increased risk of adverse effects; use with caution and at the lowest effective dose.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, other NSAIDs, or any component of the formulation.
* History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
* Perioperative pain in the setting of coronary artery bypass graft (CABG) surgery.
* Active gastrointestinal (GI) bleeding or history of recurrent GI bleeding.
* Severe renal, hepatic, or cardiac impairment.
* Third trimester of pregnancy.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, dyspepsia, dizziness, rash.
* **Serious:**
* **GI:** Gastrointestinal bleeding, ulceration, perforation.
* **Cardiovascular:** Increased risk of myocardial infarction, stroke, and heart failure.
* **Renal:** Acute kidney injury, interstitial nephritis.
* **Hepatic:** Hepatotoxicity, elevated liver enzymes.
* **Hematologic:** Anemia, leukopenia.
* **Dermatologic:** Stevens-Johnson syndrome, toxic epidermal necrolysis.
* **Hypersensitivity:** Anaphylaxis, bronchospasm.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Corticosteroids:** Increased risk of GI ulceration and bleeding.
* **SSRIs/SNRIs:** Increased risk of GI bleeding.
* **ACE inhibitors/ARBs:** Reduced antihypertensive effect; increased risk of renal impairment.
* **Diuretics:** Reduced diuretic and antihypertensive effect; increased risk of renal impairment.
* **Lithium:** Increased lithium levels and toxicity.
* **Methotrexate:** Increased risk of methotrexate toxicity.
## Monitoring
* **GI symptoms:** Monitor for signs and symptoms of bleeding or ulceration.
* **Renal function:** Monitor BUN, creatinine, especially in patients with pre-existing renal disease or those receiving concomitant nephrotoxic agents.
* **Hepatic function:** Monitor liver enzymes, especially with prolonged use or in patients with hepatic impairment.
* **Blood pressure:** Monitor for increases, particularly in patients with hypertension.
* **Signs of hypersensitivity:** Monitor for rash, difficulty breathing.
## Clinical Pearls
* Administer with food or milk to minimize GI upset.
* Short-term use is preferred due to the risk of serious adverse effects.
* Consider risks vs. benefits, especially in elderly patients or those with pre-existing cardiovascular, renal, or GI disease.
* Lowest effective dose for the shortest duration necessary should be used.
* Avoid concurrent use with other NSAIDs or aspirin unless specifically indicated and under close supervision.
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**Disclaimer:** This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and product labeling for complete details and to ensure patient safety. Local protocols and guidelines may differ.
