Exercise-induced asthma and doxantrazole.

In a double-blind cross-over trial in 13 patients with exercise-induced asthma, doxantrazole 200 mg taken orally 1 hour before a standardized exercise test involving stair climbing failed to block post-exercise bronchoconstriction. In an open assessment study with the same patients, increasing the doxantrazole dose to 400 mg did not affect post-exercise bronchoconstriction.