Flonase is a medication used to relieve seasonal and year-round allergic and non-allergic nasal symptoms, such as stuffy/runny nose, itching, and sneezing. It can also help relieve allergy eye symptoms such as itchy, watery eyes. Flonase belongs to a class of drugs known as corticosteroids, and it works in the nose to block the effects of substances that cause allergies (such as pollen, pet dander, dust mites, mold) and to reduce swelling. Flonase helps decrease inflammation in the nose, making it easier to breathe. It is available in different brand names such as ClariSpray, Flonase, Flonase Allergy Relief, Flonase Sensimist, Veramyst, and XHANCE. Flonase nasal sprays must be used as directed to get maximum benefit, and the correct dosage varies by product and age. Flonase is usually well-tolerated, but long-term use or high doses may increase the risk of having side effects such as a serious allergic reaction, hormonal (adrenal gland) disorder, nose sores, a yeast (fungal) infection in your throat or nose, a higher risk of infections, cataracts or glaucoma, weak bones or osteoporosis, and delayed growth in children.