Comparative inhibitory activity of etoricoxib, celecoxib, and diclofenac on COX-2 versus COX-1 in healthy subjects.

We determined cyclo-oxygenase-1 and cyclo-oxygenase-2 inhibition in healthy middle-aged subjects (41-65 years) randomly assigned to four 7-day treatment sequences of etoricoxib 90 mg every day, celecoxib 200 mg twice a day, diclofenac 75 mg twice a day, or placebo in a double-blind, randomized, 4-period crossover study. Maximum inhibition of thromboxane B(2) (cyclo-oxygenase-1 activity) in clotting whole blood on day 7 (0-24 hours postdose) was the primary endpoint. Inhibition of lipopolysaccharide-induced prostaglandin E(2) in whole blood (cyclo-oxygenase-2 activity) was assessed on day 7 (0-24 hours postdose) as a secondary endpoint.