The effect of valdecoxib (40 mg, PO) and placebo on algosity (panel A) and unpleasantness (panel B) of the supra-maximal pain stimulus. The pain intensity is expressed in the visual analog scale of pain units (0 = no pain, 100 = maximum pain) as mean ± SD. Time scale indicates the time (in min) after study drug or placebo administration and when the pain measurements were performed. Black columns represent valdecoxib administration; white columns represent placebo administration. The results were compared using the Wilcoxon signed ranks test.