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# Mefenamic Acid (Meftal-P)
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) belonging to the fenamate class. It has analgesic, anti-inflammatory, and antipyretic properties.
## Primary Indications
* Short-term relief of mild to moderate pain, including:
* Dysmenorrhea
* Headache
* Dental pain
* Musculoskeletal pain
## Adult Dosing
* **Initial dose:** 500 mg orally every 4 to 6 hours as needed.
* **Maximum dose:** 1500 mg per day. Duration of use typically not to exceed 7 days.
## Pediatric Dosing
* Generally not recommended for children under 14 years of age due to lack of established safety and efficacy data, and potential for serious adverse effects.
## Dose Adjustments
* **Renal Impairment:** Use with caution. May require dose reduction or discontinuation depending on severity.
* **Hepatic Impairment:** Use with caution. May require dose reduction or discontinuation.
## Contraindications
* Hypersensitivity to mefenamic acid or other NSAIDs.
* History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
* Peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery.
* Active gastrointestinal bleeding or a history of recurrent GI ulcers or bleeding.
* Severe renal or hepatic impairment.
* Third trimester of pregnancy.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, dyspepsia, headache, dizziness.
* **Serious:**
* Gastrointestinal: Bleeding, ulceration, perforation.
* Cardiovascular: Increased risk of myocardial infarction, stroke, and heart failure.
* Renal: Renal dysfunction, interstitial nephritis, papillary necrosis.
* Hepatic: Hepatotoxicity.
* Hematologic: Anemia, thrombocytopenia.
* Hypersensitivity reactions: Rash, Stevens-Johnson syndrome, toxic epidermal necrolysis.
* Fluid retention and edema.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Aspirin:** May reduce the cardioprotective effect of low-dose aspirin; increased risk of GI toxicity.
* **Corticosteroids:** Increased risk of GI ulceration and bleeding.
* **Diuretics, ACE inhibitors, ARBs:** May reduce antihypertensive effect and increase risk of renal impairment.
* **Lithium:** Increased lithium levels and toxicity.
* **Methotrexate:** Increased risk of methotrexate toxicity.
## Monitoring
* **Renal function:** Monitor electrolytes and creatinine, especially in patients with pre-existing renal disease or those at risk.
* **Hepatic function:** Monitor liver enzymes, especially with long-term use or in patients with liver disease.
* **Gastrointestinal symptoms:** Assess for signs and symptoms of bleeding or ulceration.
* **Blood pressure:** Monitor for potential increases in blood pressure.
## Clinical Pearls
* Mefenamic acid should be taken with food or milk to minimize gastrointestinal upset.
* It is intended for short-term use only.
* Due to its potential for serious adverse effects, especially gastrointestinal and cardiovascular, it should be used at the lowest effective dose for the shortest duration necessary.
* Avoid concomitant use with other NSAIDs.
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**Disclaimer:** This information is intended for clinical use and does not replace the need to consult the official prescribing information and professional judgment. Always verify current dosing, indications, contraindications, warnings, precautions, and adverse reactions with the most up-to-date drug product labeling or a reliable drug information resource.
