Nasal sprays are commonly used to treat sinusitis, allergies, rhinitis and hay fever. They are also used for the nasal delivery of sinus medication as topical therapy to generally 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.

Allergy nasal sprays are the most effective medications for the treatment of nasal allergy symptoms. They're even better than oral antihistamines. Nasal sprays do, however, have a downside: They need to be used routinely to get the best results, and many people do not like the idea of putting medication in their nose. Side effects of nasal sprays are typically limited to nasal irritation or nose bleeds; few sprays cause any significant, body-wide side effects. Some may experience a bad taste or smell, burning sensation, or drainage in the throat.

The three main types available for local effect are: antihistamines, corticosteroids, and topical decongestants.

Topical Nasal Antihistamines

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. At the present time, there is only one medication in this category: Azelastine (Astelin). Astelin is effective in treating allergic and non-allergic rhinitis. It treats all nasal symptoms, similar to nasal steroids, and should be used routinely for results. It is available by prescription only and has gained popularity with sufferers of allergic rhinitis.

Side effects are generally mild and include nasal irritation. Some have reported sleepiness, too, as it is an older antihistamine similar to diphenhydramine (Benadryl).

Topical Nasal Steroids

This type of allergy and/or sinus medication is probably the most effective at treating nasal allergies, as well as non-allergic rhinitis. There are many topical therapy nasal steroids on the market, and all are available only by prescription. Some people note that one smells or tastes better than another, but they all work about the same. Topical nasal steroids include fluticasone propionate (Flonase), mometasone (Nasonex), budesonide (Rhinocort Aqua), flunisolide (Nasarel), triamcinolone (Nasacort AQ) and beclomethasone (Beconase AQ). Fluticasone furoate (Veramyst) is the newest nasal steroid of the market; it even appears to be helpful in the treatment of eye allergies.

Topical decongestants

Topical decongestants are medicines applied directly to the nasal cavity in order to clear congestion. Typically, topical decongestants work more quickly and are more effective than oral decongestants. Topical decongestants should be used for no more than three days in a row, as overuse can lead to congestion worse than the original problem.

Oxymetazoline hydrochloride decongestant nasal sprays such as Afrin and Vicks Sinex, along with phenylephrine hydrochloride nasal sprays such as Neo Synephrine and Dristan, which are available over-the-counter 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. 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.