The effect of an increase in inhaled allergen dose after terfenadine on the occurrence and magnitude of the late asthmatic response

摘要

SummaryWe have attempted to use a potent and selective histamine H1‐receptor antagonist terfenadine to allow a larger dose of allergen to be administered to previous single early responders to investigate if an increased dose of allergen could induce a late asthmatic response. Pre‐treatment with 180 mg of terfenadine enabled a geometric mean increase in allergen dose of 412‐fold to be inhaled by eight atopic subjects with mild asthma, who initially were classified as single early responders, with maximal fall in FEV13–8 hr after allergen challenge (Lmax) of10 even with a 1.29–2.66‐fold increase in allergen dose. For the group as a whole an increase in allergen dose was associated with an increase in overall bronchoconstrictor response 3–8 hr after challenge. These results indicate that it is possible to induce a late asthmatic response in a subject who previously demonstrated only an early response by increasing the d