Flonase treats the source of nasal problems by reducing the swelling or inflammation in the nose that brings on these symptoms in the first place. This reduces the symptoms of nasal congestion, runny nose, postnasal drip and sneezing. Flonase starts working within 12 hours, but it may take several days to achieve maximum relief.

Flonase belongs to a class of medications called nasal steroids, but not the type of steroids related to bodybuilding. Nasal steroids are very much like natural bodily substances that work to reduce inflammation. They are very gentle to a person's system and are not habit-forming.