Please check your internet connection and try again.
# Mefenamic acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic and anti-inflammatory properties. It works by inhibiting cyclooxygenase (COX) enzymes, reducing 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: 1500 mg. Treatment should not exceed 7 days.
* **Dysmenorrhea:** 500 mg every 6 hours starting with the onset of bleeding and associated symptoms. Treatment should not exceed 3 days per menstrual cycle.
## Pediatric Dosing
Mefenamic acid is generally **not recommended for use in children under 14 years of age** due to concerns regarding safety and efficacy, particularly the risk of Reye's syndrome with viral illnesses.
## Dose Adjustments
No specific dose adjustments are typically required for renal or hepatic impairment, but caution is advised. Mefenamic acid is generally **contraindicated in severe renal or hepatic impairment**.
## Contraindications
* Known hypersensitivity to mefenamic acid or other NSAIDs.
* History of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
* Peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery.
* Inflammatory bowel disease.
* Severe heart failure, renal impairment, or hepatic impairment.
* Third trimester of pregnancy.
## Adverse Effects
* **Common:** Gastrointestinal upset (nausea, vomiting, diarrhea, abdominal pain, constipation), dyspepsia, headache, dizziness, rash.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; cardiovascular thrombotic events (myocardial infarction, stroke); renal toxicity; hepatic toxicity; 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.
* **Lithium:** Increased serum lithium levels, potentially leading to toxicity.
* **Methotrexate:** Increased methotrexate levels and toxicity.
* **Diuretics, ACE inhibitors, Angiotensin II Receptor Blockers:** Reduced antihypertensive effect and increased risk of renal toxicity.
## Monitoring
* **Baseline and periodic monitoring of renal function (creatinine, BUN).**
* **Baseline and periodic monitoring of liver function tests (LFTs).**
* **Monitor for signs and symptoms of gastrointestinal bleeding.**
* **Monitor for signs and symptoms of cardiovascular events.**
* **Monitor for signs and symptoms of hypersensitivity reactions.**
## Clinical Pearls
* Mefenamic acid is generally for **short-term use only** due to increased risk of adverse events with prolonged therapy.
* Administer with food or milk to minimize gastrointestinal upset.
* Avoid concomitant use with other NSAIDs.
* Consider risks versus benefits, especially in elderly patients or those with pre-existing cardiovascular, renal, or hepatic disease.
***
**Disclaimer:** This information is intended for healthcare professional use. It is essential to consult the most current prescribing information and relevant clinical guidelines for definitive patient management decisions. Local institutional protocols may also apply.
