Effect of systemically administered H1- and H2-receptor antagonists on nasal blood flow as measured with laser Doppler flowmetry in a provoked allergic reaction.
Twelve subjects with seasonal allergic rhinitis were challenged topically with birch pollen extract in a double-blind, double-dummy, placebo-controlled, randomized cross-over study. Pre-treatment was performed with either a selective histamine-1 (H1-) antagonist (terfenadine), a selective H2-antagonist (cimetidine), a combination of these drugs or a placebo. Nasal mucosa microcirculatory blood flow was measured with the use of laser Doppler flowmetry. The allergen challenge induced a decrease in the microcirculatory blood flow of the nasal mucosa. Pre-treatment with the H1-antagonist inhibited this effect and allergic symptoms, while pre-treatment with the H2-antagonist did not. No signs of an additive effect were seen after combination of the antagonists. Thus, H1-receptors but not H2-receptors, seem to be of importance in the pathophysiology of the allergic rhinitis.
Juliusson
S
S
Department of Chest Medicine, Vifilstadir, Gardabaer, Iceland.
Bende
M
M
D000328:Adult; D000485:Allergens; D002927:Cimetidine / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D009297:Nasal Mucosa / Q000098:blood supply*; D009299:Nasal Provocation Tests; D011058:Pollen; D011292:Premedication; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000503:physiopathology*; D016593:Terfenadine / Q000494:pharmacology*
D000485:Allergens; D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D016593:Terfenadine; D002927:Cimetidine