Effect of ibudilast: a novel antiasthmatic agent, on airway hypersensitivity in bronchial asthma.

Ibudilast, a unique agent with vasodilating and antiallergic actions, was studied in 13 asthmatics for its effect on airway hypersensitivity to histamine inhalation. The PC20 values improved significantly from 355.6 to 620.5 micrograms/ml at 3 months and further to 731.4 micrograms/ml at 6 months following the initial treatment with ibudilast (20 mg twice daily orally). In addition, the severity of the attacks decreased significantly. Improvements in the PC20 and asthmatic symptoms also were observed in the disodium chromoglycate group, but these were equal to or lesser than those in the ibudilast group. No improvement was observed in the untreated control group. These results suggest that ibudilast would be an effective agent for improving nonspecific airway hypersensitivity in asthmatics.