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 acts by inhibiting cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis.
## Primary Indications
* **Pain:** Relief of mild to moderate pain, including menstrual pain (dysmenorrhea), dental pain, and musculoskeletal pain.
* **Inflammation:** Reduction of inflammation associated with various conditions.
## Adult Dosing
* **Pain:** 500 mg every 6 to 8 hours as needed.
* **Dysmenorrhea:** 500 mg initially, followed by 250 mg every 6 hours as needed.
* **Maximum daily dose:** 1500 mg (for short-term use only). Some sources suggest a maximum of 1000 mg on the first day of treatment.
## Pediatric Dosing
Mefenamic acid is **not recommended** for use in children under 14 years of age due to lack of established safety and efficacy.
## Dose Adjustments
* **Renal Impairment:** Use with caution. Significant impairment may require dose reduction or avoidance.
* **Hepatic Impairment:** Use with caution. Dose adjustments may be necessary based on individual response and liver function.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, other NSAIDs, or any component of the formulation.
* History of bronchospasm, asthma, 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.
* Active gastrointestinal (GI) bleeding or history of GI bleeding/perforation related to prior NSAID use.
* Severe renal impairment.
* Severe hepatic impairment.
* Severe heart failure.
* Third trimester of pregnancy.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, dyspepsia, headache, dizziness.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; renal toxicity (including interstitial nephritis, papillary necrosis); hepatotoxicity; cardiovascular thrombotic events (myocardial infarction, stroke); bronchospasm; 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.
* **Selective Serotonin Reuptake Inhibitors (SSRIs) / Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs):** Increased risk of GI bleeding.
* **Other NSAIDs (including aspirin):** Increased risk of GI toxicity, renal toxicity, and other adverse effects.
* **Lithium:** Increased lithium levels and potential for toxicity.
* **Methotrexate:** Increased risk of methotrexate toxicity.
* **Diuretics:** Reduced diuretic efficacy; increased risk of renal impairment.
* **ACE Inhibitors/Angiotensin II Receptor Blockers (ARBs):** Increased risk of renal impairment and decreased antihypertensive effect.
## Monitoring
* **GI Symptoms:** Monitor for signs and symptoms of GI bleeding (e.g., melena, hematemesis).
* **Renal Function:** Periodic assessment of renal function, especially in patients with pre-existing renal disease or those at risk.
* **Hepatic Function:** Periodic assessment of liver function.
* **Blood Pressure:** Monitor blood pressure, particularly in patients with hypertension.
* **Signs of Cardiovascular Events:** Educate patients on signs and symptoms of MI and stroke.
## Clinical Pearls
* Use the lowest effective dose for the shortest duration necessary to minimize risks.
* Administer with food or milk to reduce GI upset.
* Mefenamic acid should not be used for more than 7 consecutive days due to potential for GI toxicity.
* Consider GI protection (e.g., proton pump inhibitor) for patients at high risk of GI complications.
---
**Disclaimer:** This information is for educational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for diagnosis and treatment. Verify current prescribing information and guidelines before making any clinical decisions.
