IC50) er 0, 0369 til 0, 12 µM, hvorimod IC50 for COX- 1 er 20, 14 – 33, 1 µM.
The concentration of firocoxib required to inhibit 50% of the COX-2 enzyme (i. e., the IC50) is 0.0369 to 0.12 µM, whereas the IC50 for COX-1 is 20.14 to 33.1 µM.