biostudies-literatureUnknown10(1)North ML<h4>Background</h4>Oral antihistamines that target the histamine receptor-1, such as fexofenadine, offer suboptimal relief of allergic rhinitis-associated nasal congestion. Combinations with oral sympathomimetics, such as pseudoephedrine, relieve congestion but produce side effects. Previous animal and human studies with histamine receptor-3 antagonists, such as PF-03654764, demonstrate promise.<h4>Methods</h4>Herein we employ the Environmental Exposure Unit (EEU) to conduct the first randomized controlled trial of PF-03654764 in allergic rhinitis. 64 participants were randomized in a double-blind, placebo-controlled 4-period crossover study. Participants were exposed to ragweed pollen for 6 hours post-dose in the EEU. The primary objective was to compare the effect of PF-03654764 + fexofeAllergy, asthma, and clinical immunology : official journal of the Canadian Society of Allergy and Clinical Immunology33https://www.ebi.ac.uk/biostudies/studies/S-EPMC4094756biostudies-literatureAdd-on histamine receptor-3 antagonist for allergic rhinitis: a double blind randomized crossover trial using the environmental exposure unit.PMC4094756North MLSteacy LMHackman FEllis AKAllan RJHobsbawn BGSun XDay AGWalker TJfalseAdd-on histamine receptor-3 antagonist for allergic rhinitis: a double blind randomized crossover trial using the environmental exposure unit.<h4>Background</h4>Oral antihistamines that target the histamine receptor-1, such as fexofenadine, offer suboptimal relief of allergic rhinitis-associated nasal congestion. Combinations with oral sympathomimetics, such as pseudoephedrine, relieve congestion but produce side effects. Previous animal and human studies with histamine receptor-3 antagonists, such as PF-03654764, demonstrate promise.<h4>Methods</h4>Herein we employ the Environmental Exposure Unit (EEU) to conduct the first randomized controlled trial of PF-03654764 in allergic rhinitis. 64 participants were randomized in a double-blind, placebo-controlled 4-period crossover study. Participants were exposed to ragweed pollen for 6 hours post-dose in the EEU. The primary objective was to compare the effect of PF-03654764 + fexofe2014-01-01T00:00:00Z20142026-04-29T12:39:39.158Z2019-03-27T01:31:56ZS-EPMC40947562502471610.1186/1710-1492-10-33