Nasal sprays are used for the nasal delivery of a drug or drugs, generally to alleviate cold or allergy symptoms such as nasal congestion. Although delivery methods vary, most nasal sprays function by instilling a fine mist into the nostril by action of a hand-operated pump mechanism. The three main types available are: antihistamines, corticosteroids, and topical decongestants.
Excessive histamine function is the primary cause of allergic reactions in people. Histamine is a chemical naturally produced by the body which creates an inflammatory effect to help the immune system remove foreign substances. Antihistamines work by competing for receptor sites to block the function of histamine, thereby reducing the inflammatory effect.
Steroidal nasal sprays, also available only by prescription, use the anti-inflammatory effect of a corticosteroid to reduce swelling and congestion in the nasal passages and sinuses. Examples include Nasonex, Flonase, Nasacort, and Rhinocort. They generally take a week to ten days to reach their maximum effectiveness, and are considered safe for extended use.
Oxymetazoline hydrochloride decongestant nasal sprays such as Afrin and Vicks Sinex, which are available over-the-counter in the United States and the UK, work to very quickly open up nasal passages by constricting blood vessels in the lining of the nose.
Prolonged use of these types of sprays can damage the delicate mucous membranes in the nose. Ironically, this causes increased inflammation, an effect known as rhinitis medicamentosa, or the "rebound effect". As a result, decongestant nasal sprays are advised for short-term use only.
Nasal salves have been shown to improve respiratory discomfort caused by the increased dryness of air in pressurized air flight and some air conditioned offices (sick building syndrome) They have been shown to reduce susceptibility to various flight related respiratory infections.
Frequently, a doctor or allergist will prescribe several types of nasal sprays in combination with each other or with other drugs. For example, a decongestant spray is often advised for the first few days of treatment in conjunction with an antihistamine or steroidal spray. The quick-acting effects of the decongestant allow for better initial delivery of the other sprays.