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# Mefenamic Acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) belonging to the fenamate class. It exhibits analgesic and anti-inflammatory properties.
## Primary Indications
* Short-term management of mild to moderate pain.
* Management of primary dysmenorrhea.
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Do not exceed 4000 mg per day.
* **Dysmenorrhea:** 500 mg every 4-6 hours as needed, starting with the onset of pain and bleeding. Do not exceed 4000 mg per day.
## Pediatric Dosing
Mefenamic acid is generally not recommended for pediatric patients under 14 years of age due to limited data and potential risks. Specific pediatric dosing is not established.
## Dose Adjustments
* **Renal Impairment:** Use with caution. A dose reduction may be necessary based on the degree of impairment. Data is limited.
* **Hepatic Impairment:** Use with caution. A dose reduction may be necessary based on the degree of impairment. Data is limited.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, or other NSAIDs.
* History of bronchospasm, asthma, rhinitis, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs.
* Perioperative pain in the setting of coronary artery bypass graft (CABG) surgery.
## Adverse Effects
* **Common:** Diarrhea, nausea, vomiting, abdominal pain, headache, dizziness, rash.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; cardiovascular thrombotic events; renal toxicity; hepatic toxicity; hypersensitivity reactions; Stevens-Johnson syndrome/toxic epidermal necrolysis.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Corticosteroids:** Increased risk of gastrointestinal bleeding and ulceration.
* **Selective Serotonin Reuptake Inhibitors (SSRIs):** Increased risk of gastrointestinal bleeding.
* **Other NSAIDs (including aspirin):** Increased risk of adverse effects, particularly gastrointestinal.
* **Diuretics, ACE inhibitors, Angiotensin II Receptor Blockers (ARBs):** Reduced antihypertensive effect; increased risk of renal dysfunction.
* **Lithium:** Increased serum lithium levels.
* **Methotrexate:** Increased risk of methotrexate toxicity.
## Monitoring
* **Renal function:** Baseline and periodically, especially in patients with pre-existing renal disease or those at risk.
* **Hepatic function:** Baseline and periodically, especially in patients with pre-existing hepatic disease or those at risk.
* **Signs and symptoms of gastrointestinal bleeding.**
* **Blood pressure:** NSAIDs can increase blood pressure.
## Clinical Pearls
* Mefenamic acid should be used at the lowest effective dose for the shortest duration necessary.
* Take with food or milk to minimize gastrointestinal upset.
* Discontinue use and seek medical attention if signs of gastrointestinal bleeding or ulceration occur.
* Avoid concurrent use with other NSAIDs.
* Consider risks of cardiovascular and renal events, especially in higher-risk patients.
**Disclaimer:** This information is intended for healthcare professionals. Always consult the most current prescribing information and relevant clinical guidelines before making any treatment decisions. Local protocols may influence specific dosing and management strategies.
