 Subjects who are using some of the medications below on an as needed basis, may participate in the study if they remain free of medication for the following periods of time prior to screening and prior to dosing study drugs: Nasal antihistamines: 72 hours, Oral antihistamines A cetirizine, fexofenadine, loratadine, desloratadine: 72 hours, Oral antihistamines B all others: 72hours, Eye and Nasal Levocasbastine: 7 days, Nasal decongestants: 24 hours, Oral decongestants: 24 hours, Nasal glucocorticosteroids: 7 days, Inhaled glucocorticoids: 1 week, Oral glucocorticosteroids: 12 weeks, Oral leukotriene receptor antagonists: 7 days, Oral 5-lipoxygenase inhibitors: 7 days, Oral methylxanthines: 7 days 