A non-steroidal anti-inflammatory agent with analgesic, anti-inflammatory, and antipyretic properties. It is an inhibitor of cyclooxygenase. [PubChem]
Indication
For the treatment of rheumatoid arthritis, osteoarthritis, dysmenorrhea, and mild to moderate pain, inflammation, and fever.
Pharmacology
Mefenamic acid, an anthranilic acid derivative, is a member of the fenamate group of nonsteroidal anti-inflammatory drugs (NSAIDs). It exhibits anti-inflammatory, analgesic, and antipyretic activities. Similar to other NSAIDs, mefenamic acid inhibits prostaglandin synthetase.
Toxicity
Oral, rat LD50: 740 mg/kg. Symptoms of overdose may include severe stomach pain, coffee ground-like vomit, dark stool, ringing in the ears, change in amount of urine, unusually fast or slow heartbeat, muscle weakness, slow or shallow breathing, confusion, severe headache or loss of consciousness.
Affected Organisms
Humans and other mammals
Biotransformation
Mefenamic acid undergoes metabolism by CYP2C9 to 3-hydroxymethyl mefenamic acid, and further oxidation to a 3-carboxymefenamic acid may occur. The activity of these metabolites has not been studied. Mefenamic acid is also glucuronidated directly.
Absorption
Mefenamic acid is rapidly absorbed after oral administration.
Half Life
2 hours
Protein Binding
90%
Elimination
The fecal route of elimination accounts for up to 20% of the dose, mainly in the form of unconjugated 3-carboxymefenamic acid.3 The elimination half-life of mefenamic acid is approximately two hours. Mefenamic acid, its metabolites and conjugates are primarily excreted by the kidneys. Both renal and hepatic excretion are significant pathways of elimination.
Application An NSAID. Circumvents MRP-mediated multidrug resistance. Specifically and significantly potentiates the cytotoxicity of anthracyclines (doxorubicin, daunorubicin and epirubicin), as well as teniposide, VP-16 and vincristine. Other Notes Tandem Mass Spectrometry data independently generated by Scripps Center for Metabolomics is available to view or download in PDF. M4267.pdf Tested metabolites are featured on Scripps Center for Metabolomics METLIN Metabolite Database. To learn more, visit sigma.com/metlin.
An aminobenzoic acid that is anthranilic acid in which one of the hydrogens attached to the nitrogen is replaced by a 2,3-dimethylphenyl group. Although classed as a non-steroidal anti-inflammatory drug, its anti-inflammatory properties are considered to be minor. It is used to relieve mild to moderate pain, including headaches, dental pain, osteoarthritis and rheumatoid arthritis.
References
PubChem Literature
From Data Sources
• Winder, C.V., J. Pharmacol. Exp. Ther., 138, 405 (1962)
Harmful (Xn)