 Medication Exclusion Period Prior to Visit 1 Intranasal and ocular corticosteroids 28 days Leukotriene modifiers e.g., Singulair, Accolate, Zyflo 28 days Intranasal and ocular cromolyn 14 days Long-acting antihistamines e.g., loratadine, cetirizine 10 days Short-acting antihistamines includes prescription and OTC 72 hours Oral and intranasal decongestants 72 hours Intranasal anticholinergics e.g., Atrovent 24 hours 