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 exerts analgesic and anti-inflammatory effects primarily through the inhibition of cyclooxygenase (COX) enzymes, thereby 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 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, not to exceed 7 days.
## Pediatric Dosing
Mefenamic acid is generally not recommended for use in children under 14 years of age due to limited data and potential for adverse effects. When used, dosing must be individualized and carefully monitored. Specific pediatric dosing is not well-established.
## Dose Adjustments
No specific dose adjustments are routinely recommended for renal or hepatic impairment. However, caution and close monitoring are advised in patients with pre-existing renal or hepatic disease due to the potential for NSAID-induced toxicity.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, or other NSAIDs.
* History of NSAID-induced bronchospasm, asthma, rhinitis, or urticaria.
* Perioperative pain in the setting of coronary artery bypass graft (CABG) surgery.
* Inflammatory bowel disease.
* Active peptic ulceration or gastrointestinal bleeding.
* Severe renal or hepatic impairment.
* Severe heart failure.
* Pregnancy (third trimester).
## Adverse Effects
**Common:** Nausea, vomiting, diarrhea, abdominal pain, constipation, dyspepsia, flatulence, headache, dizziness, rash.
**Serious:** Gastrointestinal bleeding, perforation, ulceration; renal failure; hepatic failure; cardiovascular thrombotic events (MI, stroke); hypersensitivity reactions (including anaphylaxis and Stevens-Johnson syndrome); exacerbation of asthma; hypertension; fluid retention and edema.
## Key Drug Interactions
* **Anticoagulants (e.g., warfarin):** Increased risk of bleeding. Monitor INR closely.
* **Corticosteroids:** Increased risk of gastrointestinal ulceration and bleeding.
* **Selective Serotonin Reuptake Inhibitors (SSRIs) / Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs):** Increased risk of gastrointestinal bleeding.
* **Lithium:** Increased lithium levels and potential toxicity. Monitor lithium levels.
* **Methotrexate:** Increased methotrexate levels and toxicity.
* **Diuretics and Antihypertensives:** Reduced antihypertensive effect; increased risk of renal impairment.
* **Other NSAIDs (including aspirin):** Increased risk of adverse effects, particularly gastrointestinal bleeding.
## Monitoring
* **Renal function:** Especially in elderly patients or those with pre-existing renal disease.
* **Hepatic function:** Particularly with prolonged use or in patients with hepatic impairment.
* **Gastrointestinal symptoms:** Monitor for signs of bleeding (e.g., melena, hematemesis).
* **Blood pressure:** NSAIDs can cause or worsen hypertension.
* **Signs of hypersensitivity reactions.**
## Clinical Pearls
* Mefenamic acid should be taken with food or milk to minimize gastrointestinal upset.
* Due to its short duration of action and potential for gastrointestinal toxicity, it is generally used for short-term pain management rather than chronic inflammatory conditions.
* Should be used at the lowest effective dose for the shortest duration necessary to control symptoms.
* Discontinue use if signs of gastrointestinal bleeding or ulceration occur.
***
**Disclaimer:** This information is intended for healthcare professionals and does not substitute for comprehensive drug information resources. Always consult the current prescribing information and relevant guidelines before making clinical decisions.
