Pharmacology: Pharmacokinetics: Mefenamic acid is absorbed from the gastrointestinal tract. Peak plasma concentrations occur about 2-4 hours after ingestion. The plasma elimination half-life is reported to be 2-4 hours. Mefenamic acid is extensively bound to plasma proteins. Mefenamic acid is distributed in to breast milk but the amount is considered by some authorities to be too small to be harmful to a breast-fed infant. Over 50% of a dose may be recovered in the urine as unchanged drug or conjugates of Mefenamic acid and its metabolites.