How Nasal Spray Works
Nasal sprays--or decongestant sprays, as they are sometimes called--are sold over the counter in the Unites States and go under a variety of brand names. Afrin, Sinarest, and Allerest are but three of the many variations on the same theme. These drugs are sold with the promise that they will clear up nasal decongestion. In other words, if your nose is stopped up, these medicines will let you breathe again. They do this because they include an agent that constricts the blood vessels in your nose. When you're ill, these vessels become bloated and swollen. When this happens mucus starts flowing freely, and this combination makes it hard to breathe. When the nasal spray constricts the blood vessels, it sends a signal to the nasal membranes to stop producing all that extra mucus, and the pathway to clear breathing is unobstructed.
Nasal Spray Addiction
Nasal sprays have come under attack, however, for their addictive properties. That's not to say that you can become dependant on nasal spray the way you might become addicted to nicotine or cocaine, but you can develop a tolerance for the medicine. The body knows when there is a foreign substance inside. It will do everything it can to put things backs to normal (even if normal in this instance is unpleasant for you). Your nasal blood vessels dilate even further than before, and thus require more nasal spray--in higher doses--to achieve the same effect. And the more nasal spray you use, the harder the body fights it with further blood vessel dilation (and thus more mucus production).
Kicking the Habit
As you can see, this creates a vicious circle, and can lead to this nasal spray "addiction" that many people have warned about. Because of this, bottles of nasal decongestant are required to print labels which warn against using the product for more than three days in a row. If you happen to be directly in the middle of one of these vicious cycles right now, the best advice is to quit taking the nasal spray and suffer through the effects. In most cases, your nasal passages will return to normal in a matter of a couple of weeks.