title: The effects of the nasal antihistamines olopatadine and azelastine in nasal allergen provocation.
abstract: BACKGROUND
  Olopatadine, an antihistamine used in allergic conjunctivitis, is under development as a nasal preparation for the treatment of allergic rhinitis.
  
  
  OBJECTIVE
  To evaluate the efficacy of olopatadine in suppressing symptoms and biomarkers of the immediate reaction induced by nasal allergen provocation and to compare olopatadine with azelastine in the same model.
  
  
  METHODS
  The study was approved by the Johns Hopkins University institutional review board, and all subjects gave written consent. We studied 20 asymptomatic subjects with seasonal allergic rhinitis. The study had 2 randomized, double-blind, placebo-controlled, crossover phases that evaluated 2 concentrations of olopatadine, 0.1% and 0.2%. In a third exploratory phase, olopatadine, 0.1%, was compared with topical azelastine, 0.1%, in a patient-masked design. Efficacy variables were the allergen-induced sneezes, other clinical symptoms, and the levels of histamine, tryptase, albumin, lysozyme, and cysteinyl-leukotrienes (third study only) in nasal lavage fluids.
  
  
  RESULTS
  Both concentrations of olopatadine produced significant inhibition of all nasal symptoms, compared with placebo. Olopatadine, 0.1%, inhibited lysozyme levels, but olopatadine, 0.2%, inhibited histamine, albumin, and lysozyme. The effects of olopatadine, 0.1%, were comparable to those of azelastine, 0.1%.
  
  
  CONCLUSIONS
  Olopatadine, at 0.1% and 0.2% concentrations, was effective in suppressing allergen-induced nasal symptoms. At 0.2%, olopatadine provided evidence suggestive of inhibition of mast cell degranulation.
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Patrik
authors.initials: P
authors.lastname: Pipkorn
authors.forename: Candy
authors.initials: C
authors.lastname: Costantini
authors.forename: Curt
authors.initials: C
authors.lastname: Reynolds
authors.forename: Michael
authors.initials: M
authors.lastname: Wall
authors.forename: Margaret
authors.initials: M
authors.lastname: Drake
authors.forename: Alvin
authors.initials: A
authors.lastname: Sanico
authors.forename: David
authors.initials: D
authors.lastname: Proud
authors.forename: Alkis
authors.initials: A
authors.lastname: Togias
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology*; D018926:Anti-Allergic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D003233:Conjunctivitis, Allergic / Q000188:drug therapy* / Q000276:immunology; D018592:Cross-Over Studies; D003990:Dibenzoxepins / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009299:Nasal Provocation Tests; D000069605:Olopatadine Hydrochloride; D010793:Phthalazines / Q000008:administration & dosage / Q000627:therapeutic use*; D006255:Rhinitis, Allergic, Seasonal / Q000188:drug therapy* / Q000276:immunology
chemical_list: D000485:Allergens; D018926:Anti-Allergic Agents; D003990:Dibenzoxepins; D006634:Histamine H1 Antagonists; D010793:Phthalazines; D000069605:Olopatadine Hydrochloride; C020976:azelastine