Tepoxalin is a dual inhibitor of COX and 5-lipoxygenase (5-LO; IC₅₀s = 2.84 and 0.15 µM, respectively, in RBL-1 cell lysates).¹It also inhibits the activity of 12-, but not 15-, LO (IC₅₀s = 4.45 and 146.6 µM for the human platelet and rabbit reticulocyte enzymes, respectively). Tepoxalin reduces the production of thromboxane B₂and leukotriene B₄induced by the calcium ionophore A23187 in human peripheral blood mononuclear cells (PBMCs; IC₅₀s = 0.01 and 0.07 µM, respectively) and decreases epinephrine-induced platelet aggregation in human platelet-rich plasma (PRP; IC₅₀= 0.045 µM). It inhibits paw swelling in a rat model of adjuvant-induced arthritis with an ED₅₀value of 3.5 mg/kg.

1.Argentieri, D.C., Ritchie, D.M., Ferro, M.P., et al.Tepoxalin: A dual cyclooxygenase/5-lipoxygenase inhibitor of arachidonic acid metabolism with potent anti-inflammatory activity and a favorable gastrointestinal profileJ. Pharmacol. Exp. Ther.271(3)1399-1408(1994)