Comparison of the onset of H1-antagonism with acrivastine and terfenadine by histamine bronchial challenge in volunteers.

The speed of onset of H1-antagonism by 8 mg acrivastine and 60 mg terfenadine was compared by bronchial challenge of volunteers with histamine. Active treatments or placebo were administered 1 or 2 h before challenge in a double-blind, randomized, balanced crossover manner to 10 subjects. Acrivastine and terfenadine significantly attenuated the response to inhaled histamine compared to placebo. The effects of acrivastine at 1 and 2 h before challenge, and terfenadine at 2 h were indistinguishable, but that of terfenadine at 1 h was significantly less, indicating that acrivastine has a faster onset of action than terfenadine.