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# Mefenamic Acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) used for the short-term relief of mild to moderate pain and for the treatment of primary dysmenorrhea.
## Primary Indications
* Mild to moderate pain (e.g., dental pain, musculoskeletal pain)
* Primary dysmenorrhea
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Do not exceed 4000 mg per day.
* **Dysmenorrhea:** 500 mg every 6 hours starting with the onset of pain and bleeding, usually for 2-3 days.
## Pediatric Dosing
Mefenamic acid is generally not recommended for children under 14 years of age due to insufficient safety and efficacy data.
## Dose Adjustments
* **Renal Impairment:** Use with caution. Dose reduction may be necessary in severe impairment.
* **Hepatic Impairment:** Use with caution. Dose reduction may be necessary in severe impairment.
## 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 graft (CABG) surgery.
* Active gastrointestinal (GI) bleeding or history of recurrent GI ulceration or bleeding.
* Severe renal or hepatic impairment.
* Severe heart failure.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, dyspepsia, constipation, dizziness, rash.
* **Serious:** Increased risk of serious cardiovascular thrombotic events, myocardial infarction, and stroke; serious GI bleeding, ulceration, and perforation; renal failure; hepatic failure; hypersensitivity reactions.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Corticosteroids:** Increased risk of GI ulceration and bleeding.
* **Selective Serotonin Reuptake Inhibitors (SSRIs):** Increased risk of GI bleeding.
* **Lithium:** Increased serum lithium levels and risk of toxicity.
* **Methotrexate:** Increased risk of methotrexate toxicity.
* **Diuretics, ACE Inhibitors, ARBs:** Reduced antihypertensive effect and increased risk of renal impairment.
## Monitoring
* **GI bleeding:** Monitor for signs and symptoms of GI bleeding (e.g., melena, hematemesis).
* **Renal function:** Monitor renal function, especially in patients with pre-existing renal disease or those receiving concomitant nephrotoxic agents.
* **Hepatic function:** Monitor hepatic function, especially in patients with pre-existing hepatic disease.
* **Cardiovascular risk:** Assess cardiovascular risk factors.
## Clinical Pearls
* Mefenamic acid should be taken with food or milk to minimize GI upset.
* Limit use to the shortest duration necessary to control symptoms.
* Consider risks versus benefits, especially in patients with cardiovascular disease, renal impairment, or a history of GI ulceration.
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**Disclaimer:** This information is intended for clinical decision support and does not replace the need for current, comprehensive prescribing information, institutional guidelines, or professional judgment. Always verify current drug information and dosing with the most recent official product monograph or reliable drug information resource.
