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# Mefenamic Acid
## Overview
Mefenamic acid is a nonsteroidal anti-inflammatory drug (NSAID) used for the short-term relief of mild to moderate pain. It acts by inhibiting cyclooxygenase (COX) enzymes, thereby reducing prostaglandin synthesis.
## Primary Indications
* Pain associated with osteoarthritis and rheumatoid arthritis.
* Primary dysmenorrhea.
* Mild to moderate pain, including dental pain and postoperative pain.
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Maximum daily dose is 1500 mg. Treatment duration should not exceed 7 days.
* **Dysmenorrhea:** 500 mg every 6 hours, starting at the onset of pain and bleeding, and continuing for the duration of the symptoms.
## Pediatric Dosing
Mefenamic acid is generally **not recommended** for children under 14 years of age due to a lack of established safety and efficacy data.
## Dose Adjustments
* **Renal Impairment:** Use with caution. Dose reduction may be necessary in severe renal impairment.
* **Hepatic Impairment:** Use with caution. Dose reduction may be necessary in severe hepatic impairment.
## Contraindications
* Hypersensitivity to mefenamic acid 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.
* Inflammatory bowel disease (active or history).
* Severe heart failure, renal impairment, or hepatic impairment.
## Adverse Effects
* **Common:** Nausea, vomiting, diarrhea, abdominal pain, constipation, dizziness, headache, rash.
* **Serious:** Gastrointestinal bleeding, ulceration, perforation; renal toxicity; hepatic toxicity; cardiovascular thrombotic events; anaphylaxis; Stevens-Johnson syndrome; toxic epidermal necrolysis.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding.
* **Aspirin:** May decrease the cardioprotective effect of low-dose aspirin. Concurrent use is generally not recommended.
* **Corticosteroids:** Increased risk of gastrointestinal ulceration and bleeding.
* **Diuretics and Antihypertensives:** May reduce their efficacy and increase the risk of renal impairment.
* **Lithium:** Increased lithium levels and risk of toxicity.
* **Methotrexate:** Increased methotrexate toxicity.
## Monitoring
* **Renal function:** Monitor serum creatinine and BUN, especially in patients with pre-existing renal disease or those at risk.
* **Hepatic function:** Monitor LFTs, particularly with prolonged use or in patients with liver disease.
* **Gastrointestinal symptoms:** Assess for signs and symptoms of bleeding or ulceration.
* **Blood pressure:** Monitor for potential increase.
## Clinical Pearls
* Mefenamic acid should be taken with food or milk to minimize gastrointestinal upset.
* Due to its short half-life, it is typically dosed every 6 hours.
* It is generally indicated for short-term use only.
* Avoid concurrent use with other NSAIDs.
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*This information is intended for healthcare professionals. Always consult the current official prescribing information and relevant clinical guidelines for complete and up-to-date details before making any treatment decisions.*
