Mefenamic acid

Mefenamic acid

Clinical data
Trade names	Ponstel, Ponstan, others
AHFS/Drugs.com	Monograph
MedlinePlus	a681028
Pregnancy category	AU: C US: C (Risk not ruled out)
Routes of administration	by mouth
ATC code	M01AG01 (WHO)
Legal status
Legal status	AU: S2 (Pharmacy only) UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Bioavailability	90%
Protein binding	90%
Metabolism	Hepatic (CYP2C9)
Biological half-life	2 hours
Excretion	Urine (66%), faeces (20-25%)
Identifiers
IUPAC name 2-(2,3-dimethylphenyl)aminobenzoic acid
CAS Number	61-68-7 Y
PubChem CID	4044
IUPHAR/BPS	2593
DrugBank	DB00784 Y
ChemSpider	3904 Y
UNII	367589PJ2C
KEGG	D00151 Y
ChEBI	CHEBI:6717 N
ChEMBL	CHEMBL686 Y
ECHA InfoCard	100.000.467
Chemical and physical data
Formula	C15H15NO2
Molar mass	241.285 g/mol
3D model (Jmol)	Interactive image
SMILES O=C(O)c2c(Nc1cccc(c1C)C)cccc2
InChI InChI=1S/C15H15NO2/c1-10-6-5-9-13(11(10)2)16-14-8-4-3-7-12(14)15(17)18/h3-9,16H,1-2H3,(H,17,18) Y Key:HYYBABOKPJLUIN-UHFFFAOYSA-N Y
NY (what is this?)

Mefenamic acid is a member of the anthranilic acid derivatives (or fenamate) class of NSAID drugs, and is used to treat mild to moderate pain, including menstrual pain, and is sometimes used to prevent migraines associated with menstruation. It is not widely used in the United States due to its side effects and high cost compared to other NSAID drugs.

Its name derives from its systematic name, dimethylphenylaminobenzoic acid. It was discovered and brought to market by Parke-Davis in the 1960s. It became generic in the 1980s and is available worldwide under many brand names. As of 2015 the cost for a typical course of medication in the United States is more than 200 USD.

Mefenamic acid is used to treat moderate pain and menstrual pain.

There is evidence that supports the use of mefenamic acid for perimenstrual migraine headache prophylaxis, with treatment starting 2 days prior to the onset of flow or 1 day prior to the expected onset of the headache and continuing for the duration of menstruation.

Mefenamic acid is recommended to be taken with food.

Known mild side effects of mefenamic acid include headaches, nervousness, and vomiting. Serious side effects may include diarrhea, hematemesis (vomiting blood), hematuria (blood in urine), blurred vision, skin rash, itching and swelling, sore throat and fever. It has been associated with acute liver damage.

In 2008 the US label was updated with a warning concerning a risk of premature closure of the ductus arteriosus in pregnancy.

Like other members of the anthranilic acid derivatives (or fenamate) class of NSAID drugs, it inhibits both isoforms of COX and prevents formation of prostaglandins.