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# Mefenamic acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) of the fenamate class used for the short-term treatment of mild to moderate pain and for the relief of menstrual pain.
## Primary Indications
* Pain (mild to moderate)
* Primary dysmenorrhea
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Do not exceed 2000 mg in 24 hours.
* **Primary Dysmenorrhea:** 500 mg every 6 hours starting at the onset of menstrual pain and bleeding, continuing for the duration of symptoms. Do not exceed 2000 mg in 24 hours.
## Pediatric Dosing
Mefenamic acid is generally not recommended for children under 14 years of age due to limited data. Dosing in younger children, if considered, should be based on a case-by-case basis, often extrapolated from adult doses and weight-based calculations, but specific established guidelines are lacking.
## Dose Adjustments
No specific dose adjustments are required for renal or hepatic impairment, but caution is advised and monitoring is recommended due to potential for NSAID-induced organ damage. Elderly patients may be at increased risk of adverse effects.
## Contraindications
* Hypersensitivity to mefenamic acid 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 graft (CABG) surgery.
* Active gastrointestinal bleeding or ulcer disease.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, constipation, dyspepsia, rash.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; cardiovascular thrombotic events; renal failure; hepatic failure; hypersensitivity reactions; Stevens-Johnson syndrome/toxic epidermal necrolysis.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Corticosteroids:** Increased risk of GI ulceration and bleeding.
* **Diuretics and antihypertensives:** May reduce efficacy and increase risk of renal toxicity.
* **Lithium:** Increased lithium levels.
* **Methotrexate:** Increased methotrexate toxicity.
* **Other NSAIDs/Aspirin:** Increased risk of adverse effects.
## Monitoring
* Signs and symptoms of GI bleeding or ulceration.
* Renal function (serum creatinine, BUN).
* Liver function tests (LFTs).
* Blood pressure.
## Clinical Pearls
* Should be taken with food or milk to minimize gastrointestinal upset.
* Short-term use is recommended due to increased risk of serious cardiovascular and gastrointestinal events with prolonged use.
* Consider alternative analgesics for patients with a history of peptic ulcer disease or GI bleeding.
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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 relevant clinical guidelines for complete details, including contraindications, warnings, precautions, drug interactions, and adverse reactions, before making any treatment decisions.*
