Tibenelast is a potent orally active compound against anaphylactic shock induced by high dose antigen aerosol. When a lower aerosol challenge (0.05 mg/mL) is employed, bronchoconstriction is observed with a concomitant increase in lung resistance (RL) and a fall in dynamic compliance (Cdyn). Tibenelast at 25 mg/kg p.o. prevents these changes. Tibenelast is 10 times more potent than Aminophylline by i.v. administration; normalization of pulmonary function is achieved at 1 mg/kg i.v. Tibenelast is synergistic with epinephrine. The oral dose response curve of Tibenelast is enhanced with the co-administration of epinephrine. Tibenelast may be of significant value in the treatment of asthma and other respiratory diseases^[2].