Please check your internet connection and try again.
# Mefenamic Acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) belonging to the anthranilic acid derivative class. It has analgesic and anti-inflammatory properties.
## Primary Indications
* Short-term relief of mild to moderate pain, including dysmenorrhea, headache, dental pain, and musculoskeletal pain.
* Management of pain associated with osteoarthritis and rheumatoid arthritis (though less commonly used for chronic conditions due to potential for GI toxicity).
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Maximum daily dose is 1500 mg. Therapy should generally not exceed 7 days.
* **Dysmenorrhea:** 500 mg every 6 hours, starting at the onset of pain and bleeding. Therapy may be continued for up to 3 days.
## Pediatric Dosing
* Generally not recommended for children under 14 years of age. Specific pediatric dosing is not well-established and should be approached with caution.
## Dose Adjustments
* **Renal Impairment:** Use with caution. No specific dose adjustments are established, but reduce dose and monitor closely.
* **Hepatic Impairment:** Use with caution. No specific dose adjustments are established, but reduce dose and monitor closely.
* **Elderly:** Increased risk of adverse effects, particularly GI bleeding and renal events. Consider lower doses and increased monitoring.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, or other NSAIDs.
* History of NSAID-induced bronchospasm, urticaria, or allergic rhinitis.
* Perioperative pain in the setting of coronary artery bypass graft (CABG) surgery.
* Active gastrointestinal bleeding or history of GI ulceration/bleeding.
* Severe renal or hepatic impairment.
* Severe heart failure.
* Pregnancy (third trimester).
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, dyspepsia, headache, dizziness, rash.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; renal failure; hepatic failure; cardiovascular thrombotic events (MI, stroke); 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.
* **SSRIs and SNRIs:** Increased risk of GI bleeding.
* **ACE inhibitors, ARBs, Diuretics:** Reduced antihypertensive effect, increased risk of renal impairment.
* **Lithium:** Increased lithium levels and toxicity.
* **Methotrexate:** Increased methotrexate toxicity.
## Monitoring
* **Renal function:** Baseline and periodically, especially in patients with pre-existing renal disease, dehydration, or those on concomitant nephrotoxic agents.
* **Hepatic function:** Baseline and periodically.
* **Hemoglobin/Hematocrit:** Monitor for signs of GI bleeding.
* **Signs and symptoms of GI bleeding:** Black, tarry stools; hematemesis; abdominal pain.
* **Blood pressure:** Monitor for potential increases.
## Clinical Pearls
* Mefenamic acid is intended for short-term use only due to the risk of significant gastrointestinal adverse effects.
* It is generally not a first-line agent for chronic pain or inflammatory conditions.
* Administer with food or milk to minimize gastric upset.
* Advise patients to report any signs of bleeding or severe gastrointestinal distress.
***
*Disclaimer: This information is intended for healthcare professionals and does not substitute for professional medical advice. Always consult the most current prescribing information and local protocols for definitive guidance.*
