Mefenamic acid is a nonsteroidal anti-inflammatory and analgesic drug (trade name Ponstel) used to treat mild pain (especially menstrual cramps). Mefenamic acid is absorbed from the gastrointestinal tract. Peak plasma concentrations occur about 2 to 4 hours after ingestion. The plasma elimination half-life is reported to be 2 to 4 hours. Mefenamic acid is extensively bound to plasma proteins. Small amounts have been detected in breast milk. Over 50% of a dose may be recovered in the urine, as unchanged drug or conjugates of mefenamic acid and its metabolites.
Chemical name: N-[(2,3-Dimethylphenyl)Amino]Benzoic Acid
Molecular formula: C15H15NO2
Molecular weight: 241.9
Appearance: snowy white crystalline powder or granules; odorless
Action/Kinetics: Inhibits prostaglandin synthesis. Is an anti-inflammatory, antipyretic, and analgesic. Peak plasma levels: 2-4 hr; t1/2: 2-4 hr; duration: 4-6 hr. Slowly absorbed from the GI tract, metabolized by the liver, and excreted in the urine and feces.
Uses: Short-term relief ( < 1 week) of mild to moderate pain (e.g., pain associated with tooth extraction and musculoskeletal disorders). Primary dysmenorrhea. Investigational: PMS, sunburn.
Contraindications: Ulceration or chronic inflammation of the GI tract, pregnancy or possibility thereof, children under 14, and hypersensitivity to the drug.