Nasal decongestants are used to treat congestion (stuffy nose, runny nose, etc...). To understand how nasal decongestants work it is important to explain how congestion occurs. Many people think that congestion is caused when mucous (also called phlegm or nasal drainage) blocks the nasal passageways. This is only partially true. Congestion occurs when the blood vessels lining the nose become enlarged. Most nasal decongestants, therefore, cause vasoconstriction (cause the blood vessels to shrink). There are also some treatments for nasal symptoms which are antihistamines. Histamine is a molecule which causes the vessels to become larger, inflammation, itching and many symptoms that occur during an allergic reaction. Antihistamine nasal decongestants block histamine and work very well for people suffering from seasonal allergies. Nasal decongestants commonly come in the form of nasal sprays but many of the medications contained in the nasal sprays can also be taken orally.
Examples of Nasal Decongestants:
Though many nasal decongestants are available over-the-counter you should always check with your doctor or pharmacist before using a nasal decongestant.
American Academy of Otolaryngology - Head and Neck Surgery. Antihistamines, Decongestants, and Cold Remedies. Accessed: April 27, 2010 from http://www.ncbi.nlm.nih.gov/pubmed/19230461
Merriam Webster. Histamine. Accessed: April 27, 2010 from http://www.merriam-webster.com/dictionary/histamine