What is Ponstan?
Mefenamic acid is a non-steroidal anti-inflammatory drug used to treat pain, including menstrual pain. It is typically prescribed for oral administration. Its name is a contraction of its chemical name, 2-(2,3-dimethylphenyl)aminobenzoic acid. Mefenamic acid is marketed in the USA as Ponstel and is commonly known in Canada and UK as Ponstan. Ponstan is distributed by ERFA Canada 2012 Inc.
Mefenamic acid decreases inflammation (swelling) and uterine contractions by a still-unknown mechanism. However it is thought to be related to the inhibition of prostaglandin synthesis. There is also 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.
Since hepatic metabolism plays a significant role in mefenamic acid elimination, patients with known liver deficiency may be prescribed lower doses. Kidney deficiency may also cause accumulation of the drug and its metabolites in the excretory system. Therefore patients suffering from renal conditions should not be prescribed mefenamic acid.