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# Mefenamic Acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) used for the short-term management of mild to moderate pain. It works by inhibiting cyclooxygenase (COX) enzymes, thereby reducing prostaglandin synthesis.
## Primary Indications
* Short-term management of mild to moderate pain, including menstrual pain (dysmenorrhea).
## Adult Dosing
* **Pain:** 500 mg every 4 to 6 hours as needed. Maximum daily dose is 1500 mg. Treatment should not exceed 7 days.
* **Dysmenorrhea:** 500 mg every 4 to 6 hours as needed, starting at the onset of pain and bleeding.
## Pediatric Dosing
Mefenamic acid is generally not recommended for children under 14 years of age due to a lack of established efficacy and safety data.
## Dose Adjustments
No specific dose adjustments are typically required for renal or hepatic impairment, but caution is advised. Mefenamic acid should be used with caution in patients with pre-existing renal or hepatic disease.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, or other NSAIDs.
* History of bronchospasm, asthma, allergic rhinitis, or urticaria precipitated by aspirin or other NSAIDs.
* Peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery.
* Inflammatory bowel disease (active or history).
* Severe heart failure, renal impairment, or hepatic impairment.
* Third trimester of pregnancy.
## Adverse Effects
Common adverse effects include:
* Gastrointestinal: Nausea, vomiting, diarrhea, abdominal pain, dyspepsia.
* Central Nervous System: Dizziness, drowsiness.
* Other: Headache, rash.
Serious adverse effects can include:
* Gastrointestinal bleeding, ulceration, and perforation.
* Cardiovascular thrombotic events.
* Renal impairment.
* Hepatotoxicity.
* Hypersensitivity reactions.
* Agranulocytosis and other blood dyscrasias.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Corticosteroids:** Increased risk of gastrointestinal ulceration and bleeding.
* **Diuretics and Antihypertensives:** May decrease efficacy and increase risk of renal toxicity.
* **Lithium:** Increased serum lithium levels.
* **Methotrexate:** Increased risk of methotrexate toxicity.
* **Other NSAIDs:** Increased risk of adverse effects.
## Monitoring
* Monitor for signs and symptoms of gastrointestinal bleeding (e.g., melena, hematemesis).
* Monitor for signs of renal impairment (e.g., changes in urine output, elevated creatinine).
* Monitor for signs of hepatic impairment (e.g., jaundice, elevated liver enzymes).
* Monitor blood pressure, especially in patients with hypertension.
## Clinical Pearls
* Mefenamic acid is intended for short-term use only.
* Administer with food or milk to minimize gastrointestinal upset.
* Avoid concomitant use with other NSAIDs or aspirin.
* Due to potential for drowsiness, caution patients about driving or operating machinery.
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*Disclaimer: This information is intended for healthcare professionals. Always consult the current official prescribing information and relevant clinical guidelines for complete details and to confirm any dose or safety information before making clinical decisions.*
