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 is used for the short-term management of mild to moderate pain and for the treatment of primary dysmenorrhea.
## Primary Indications
* Mild to moderate pain
* Primary dysmenorrhea
## Adult Dosing
* **Pain:** 500 mg every 6 hours as needed. Do not exceed 1500 mg in the first 24 hours and 7 days of treatment.
* **Primary Dysmenorrhea:** 500 mg every 6 hours, starting at the onset of pain, bleeding, and/or other symptoms (e.g., bloating, breast tenderness) and continuing for the duration of the symptoms, usually up to 3 days.
## Pediatric Dosing
Mefenamic acid is generally not recommended for use in children under 14 years of age. Dosing for children 14 years and older is the same as for adults.
## Dose Adjustments
* **Renal Impairment:** Use with caution. Data is limited, but dose reduction may be considered in severe renal impairment.
* **Hepatic Impairment:** Use with caution. Data is limited, but dose reduction may be considered in severe hepatic impairment.
## Contraindications
* Hypersensitivity to mefenamic acid, aspirin, other NSAIDs, or any component of the formulation.
* 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 (e.g., Crohn's disease, ulcerative colitis).
* Congestive heart failure.
* Severe renal impairment.
* Severe hepatic impairment.
* Third trimester of pregnancy.
## Adverse Effects
Common adverse effects include nausea, vomiting, diarrhea, abdominal pain, dyspepsia, and constipation. Serious adverse effects include gastrointestinal bleeding, ulceration, perforation, cardiovascular thrombotic events, renal failure, hepatic failure, hypersensitivity reactions, and worsening of asthma.
## 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) and Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs):** Increased risk of bleeding.
* **Lithium:** Increased serum lithium levels and risk of toxicity. Monitor lithium levels.
* **Methotrexate:** Increased risk of methotrexate toxicity.
* **Diuretics and Antihypertensives:** NSAIDs may decrease the efficacy of these drugs and increase the risk of renal toxicity.
* **Cyclosporine:** Increased risk of nephrotoxicity.
## Monitoring
* **Signs and symptoms of GI bleeding:** Black, tarry stools, hematemesis, abdominal pain.
* **Renal function:** Especially in patients with pre-existing renal disease or those taking nephrotoxic agents.
* **Hepatic function:** Especially in patients with pre-existing hepatic disease.
* **Blood pressure:** NSAIDs can cause fluid retention and hypertension.
* **Signs and symptoms of cardiovascular events.**
## Clinical Pearls
* Mefenamic acid is intended for short-term use only due to the risk of serious adverse effects.
* It should be taken with food or milk to minimize gastrointestinal upset.
* Avoid concurrent use with other NSAIDs or aspirin unless specifically indicated and monitored.
* Discontinue use immediately if signs of hypersensitivity or serious adverse events occur.
***
*This information is intended for healthcare professionals. Always consult the most current prescribing information and local protocols for complete details.*
