Olopatadine hydrochloride nasal spray (Patanase Nasal Spray, Alcon Laboratories, TX, USA) was approved by the US FDA in 2008, and is indicated for the relief of symptoms of seasonal allergic rhinitis (SAR), also referred to as allergic rhinosinusitis. Olopatadine is an antihistamine with selective H1-receptor antagonist activity. Clinical trials of olopatadine nasal spray have demonstrated safety and efficacy in the treatment of SAR patients. With an onset of action of 30 min, olopatadine nasal spray has also been shown to improve quality of life, ability to perform work and the conduct of usual activities in SAR patients.