Nasal antihistamines and decongestants are products that contain either an antihistamine or a decongestant, in a device suitable for nasal use.
Antihistamines block the action of histamine which is released by cells in response to allergens. Nasal antihistamines relieve symptoms such as sneezing, a runny nose, or postnasal drip.
Nasal decongestants constrict dilated blood vessels within the nose, reducing swelling which allows air to flow more freely, relieving symptoms of congestion.