H1-receptor antagonists: does a dose-response relationship exist?

Objective dose-response studies of histamine receptor blockade in the skin have been performed using suppression of the histamine-induced wheal and flare. Results with second-generation H1-antagonists indicate a dose-dependent increase in histamine skin test suppression. Few dose-response studies of H1-antagonists in allergic rhinitis or chronic urticaria have been published. The manufacturers' recommend doses for H1-antagonists appear to be optimal with regard to safety and should not be exceeded, as the incidence of adverse effects may increase when higher doses are used. Also, even if higher doses are given, complete symptom relief may not occur in all patients, as total H1-blockade still leaves the effects of other chemical mediators of inflammation unopposed.