The effects of an H1-receptor antagonist, terfenadine, on histamine-induced microcirculatory changes and vasopermeability in nasal mucosa.

Abstract

We used a nonsedating, selective histamine H1-receptor antagonist, terfenadine, to investigate the effects of antihistamines on the microcirculatory changes and vascular permeability induced by topical histamine provocation challenge. We assessed the former by the laser-Doppler measurement of blood flow, volume, and red blood cell speed, and the latter by analysis of albumin/total protein ratios in nasal lavages. Terfenadine reduced the mean symptom score and permeability changes (p less than 0.05) induced by histamine in a dose-related manner. Terfenadine had no effect on blood flow or other microcirculatory parameters. We propose that vascular effects of histamine in the nasal mucosa are not mediated uniquely through the H1 receptor.