If allergies are responsible for post-nasal drip, over-the counter antihistamines (., loratadine, desloratadine, cetirizine, fexofenadine) can be used to help with symptoms. Talk to your doctor or pharmacist before starting an antihistamine. Your doctor may also prescribe a corticosteroid nasal spray (., budesonide, fluticasone, mometasone) to help. Avoiding the allergies that cause runny noses can prevent post-nasal drip from happening again. Many people are allergic only during certain seasons or times of the year, mostly to pollens, moulds, or weeds. Year-round causes of allergies include mites, animal dander, and moulds.