Orally active 5-lipoxygenase (5-LOX) inhibitor that inhibits LTB4 synthesis (IC50 values are 0.56, 2.3 and 2.6 μM in dog, rat and human blood respectively). Inhibits antigen-induced contraction of tracheal strips in vitro (IC50 = 6 μM) and exhibits antiasthmatic activity in vivo. Also weakly inhibits CYP1A2 (Ki = 66 - 98 μM).