The pharmacodynamic properties of tepoxalin, Na-salicylate and ketoprofen were determined in an intravenous lipopolysaccharide (LPS) inflammation model in broiler chickens. The drugs were administered orally at a dose of 30, 50 and 3 mg/kg, respectively. LPS administration induces an increase in the intracellular expression of interleukin (IL)-1 beta and IL-6 and the secreted IL-6 plasma concentration. Furthermore, an elevation in body temperature is noted. Despite pretreatment with a single dose of the drugs and LPS administration on the T-max of the drug after a second dose, no decrease was seen in systemic IL-6 levels. The intracellular expression of IL-1 beta in the heterophils was slightly decreased if LPS was administered in combination with each of the three drugs. Tepoxalin and Na-salicylate administration had no significant effect on the LPS-induced increase in prostaglandin E-2 plasma concentration, in contrast to ketoprofen. None of the three drugs were able to influence the elevation in body temperature after LPS administration. The pharmacokinetic properties of Na-salicylate and ketoprofen were not altered in combination with LPS administration. However, LPS significantly decreased the AUC(0 -> 6 h) of the active metabolite of tepoxalin, RWJ-20142, indicating a perfusion-limited elimination for this molecule.