Pharmacology: Pharmacokinetics: Celecoxib is absorbed from the gastrointestinal tract, peak plasma concentrations being achieved after about 3 hours. Protein binding is about 97%. Celecoxib is metabolised in the liver mainly by the cytochrome P450 isoenzyme CYP2C9; the three identified metabolites are inactive as inhibitors of COX-1 or COX-2 enzymes. It is eliminated mainly as metabolites in the faeces and urine; less than 3% is recovered as unchanged drug. The effective terminal half-life is about 11 hours.