Evaluate single dose (2 x 2.5mcg/puff; total dose 5mcg) effect of tiotropium administered 30 minutes prior to allergen challenge on allergen-induced EAR assessed as the maximal % fall in FEV1 after allergen inhalation compared to that of single dose (two puffs) matched placebo administered 30 minutes prior to allergen challenge.
age (years) at least 18 years
no confounding health issue (i.e. no health conditions, other than asthma, that would put the participant at risk or affect data integrity as determined by the principal investigator)
baseline FEV1 ≥ 65% of predicted normal at Visit 1
evidence of atopy to an allergen suitable for inhalation challenge following skin prick testing such as house dust mite, grass, cat or horse
Smoker >10 pack year history