Why can't you use over-the-counter nasal sprays for more than three days in a row?
In general, decongestant nasal sprays should be used only on a short-term basis because using them long-term can lead to "rebound" nasal congestion. This condition primarily is caused by or worsened by overusing inhaled nasal decongestants.
People suffering from rebound nasal congestion may find that their nasal passages are red, swollen, obstructed, fragile, and bleed easily. The exact mechanism by which this kind of congestion occurs is unknown. Since these medications in nasal sprays work primarily by causing the blood vessels in the nose to constrict - which relieves nasal stuffiness - it is believed that the rebound nasal congestion results from a potent "rebound" dilation (opening of the blood vessels in the nose) once the medication wears off. The severity of rebound nasal congestion is proportionate to the length of time the nasal spray is used, the frequency of use, and the amount used. The symptoms of rebound nasal congestion can begin developing after just three days of nasal spray use.
Potential risks for people with high blood pressure or heart disease
Individuals with severe high blood pressure or heart disease should not use decongestant nasal sprays, and caution should be exercised by individuals with even mildly elevated blood pressure. These nasal medications can be absorbed into the bloodstream and cause an increase in blood pressure.
As always, it is recommended that you consult with your physician before taking any nasal or oral decongestant products.