An evaluation of the antihistamine activity of acrivastine and its onset in human skin.

In a double-blind, two-period crossover study, 24 healthy volunteers were evaluated to establish the time of onset of action of activity of acrivastine in suppressing the weal and flare response to intradermally injected histamine. Volunteers received single doses of 8 mg acrivastine and placebo according to a fully randomized, balanced treatment plan. Acrivastine significantly (P less than 0.002) reduced the flare response induced by 0.4 micrograms histamine challenge 15 min after oral acrivastine dosing when compared with placebo. A significant (P less than 0.001) reduction of the weal response was noted at 25 min, although trends in this direction were already present at earlier time points.