Please check your internet connection and try again.
# Mefenamic Acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) used for the short-term treatment of mild to moderate pain. It works by inhibiting prostaglandin synthesis.
## Primary Indications
* Pain associated with osteoarthritis and rheumatoid arthritis.
* Dysmenorrhea (menstrual pain).
* Mild to moderate pain.
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Do not exceed 1500 mg in the first 24 hours of treatment, and do not exceed 1000 mg in any 24-hour period thereafter.
* **Dysmenorrhea:** 500 mg every 6 hours starting with the onset of pain and continuing for the duration of dysmenorrhea.
* **Rheumatoid Arthritis/Osteoarthritis:** While not a primary indication due to potential toxicity with prolonged use, it can be used for symptom management. Dosing is typically 500 mg three times daily. This use requires careful consideration and monitoring for adverse effects.
## Pediatric Dosing
Mefenamic acid is generally not recommended for children under 12 years of age due to a lack of established safety and efficacy data.
## Dose Adjustments
* **Renal Impairment:** Use with caution. No specific dose adjustments are routinely recommended, but renal function should be closely monitored.
* **Hepatic Impairment:** Use with caution. No specific dose adjustments are routinely recommended, but liver function should be closely monitored.
## Contraindications
* 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.
* Known inflammatory bowel disease (e.g., Crohn's disease, ulcerative colitis).
* Third trimester of pregnancy.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, constipation, dizziness, rash.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; renal failure; hepatotoxicity; cardiovascular thrombotic events; hypersensitivity reactions; Stevens-Johnson syndrome/toxic epidermal necrolysis.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Corticosteroids:** Increased risk of gastrointestinal ulceration and bleeding.
* **Selective Serotonin Reuptake Inhibitors (SSRIs):** Increased risk of bleeding.
* **Other NSAIDs (including aspirin):** Increased risk of adverse effects, particularly gastrointestinal.
* **Lithium:** Increased serum lithium levels and risk of toxicity.
* **Methotrexate:** Increased risk of methotrexate toxicity.
* **Diuretics and Antihypertensives:** May decrease their efficacy and increase risk of renal toxicity.
## Monitoring
* Monitor for signs and symptoms of gastrointestinal bleeding (e.g., melena, hematemesis, abdominal pain).
* Monitor renal function (BUN, creatinine) and electrolytes, especially in patients with pre-existing renal disease or those at risk.
* Monitor liver function tests (ALT, AST), especially with prolonged use or in patients with hepatic impairment.
* Monitor blood pressure.
* Assess pain relief and functional status.
## 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.
* Be aware of the increased risk of cardiovascular thrombotic events and serious gastrointestinal events associated with NSAID use.
* Discontinue use at the first sign of rash, allergic reaction, or gastrointestinal bleeding.
***
*This information is intended for clinical use and does not substitute for professional medical advice. Always consult the most current prescribing information and relevant guidelines before initiating or modifying therapy.*
