Please check your internet connection and try again.
# Mefenamic Acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) belonging to the fenamate class. It exerts analgesic and anti-inflammatory effects primarily through the inhibition of cyclooxygenase (COX) enzymes, which reduces prostaglandin synthesis.
## Primary Indications
* Short-term management of mild to moderate pain.
* Management of primary dysmenorrhea.
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Maximum daily dose is 1500 mg. Treatment should not exceed 7 days.
* **Dysmenorrhea:** 500 mg every 6 hours as needed, starting at the onset of pain or bleeding, whichever comes first. Maximum daily dose is 1500 mg. Treatment should not exceed 3 days of menstrual bleeding.
## Pediatric Dosing
Mefenamic acid is generally not recommended for children under 14 years of age due to lack of established safety and efficacy.
## Dose Adjustments
No specific dose adjustments are required for renal or hepatic impairment, however, caution and the lowest effective dose are recommended, especially in patients with moderate to severe impairment.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, or other NSAIDs.
* History of bronchospasm, asthma, allergic or non-allergic 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.
* Inflammatory bowel disease.
* Severe heart failure.
* Pregnancy in the third trimester.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, constipation, headache, dizziness, rash.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; cardiovascular thrombotic events (myocardial infarction, stroke); renal failure; hepatotoxicity; anaphylactic reactions; exacerbation of asthma.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Aspirin:** Concurrent use can decrease NSAID efficacy and increase GI toxicity.
* **Corticosteroids:** Increased risk of GI ulceration and bleeding.
* **Diuretics and Antihypertensives:** NSAIDs can reduce their efficacy and increase risk of renal impairment.
* **Lithium:** NSAIDs can increase lithium levels.
* **Methotrexate:** NSAIDs can increase methotrexate toxicity.
## Monitoring
* Monitor for signs and symptoms of gastrointestinal bleeding (e.g., melena, hematemesis).
* Monitor renal function, especially in patients with pre-existing renal disease or those receiving concomitant nephrotoxic agents.
* Monitor liver function tests periodically.
* Assess for signs of hypersensitivity reactions.
## Clinical Pearls
* Administer with food or milk to minimize gastrointestinal upset.
* Use for the shortest duration necessary to control symptoms.
* Avoid concurrent use with other NSAIDs.
* Due to potential for GI and cardiovascular risks, consider alternative analgesics when appropriate, especially in high-risk patients.
***
**Disclaimer:** This information is intended for healthcare professionals and does not substitute for professional medical advice. Always consult the current prescribing information and your institution's protocols for the most up-to-date and comprehensive drug details.
