Long-term use of oxy- and xylometazoline nasal sprays induces rebound swelling, tolerance, and nasal hyperreactivity.

It has been suggested but never confirmed, that the severity of the rebound swelling and rhinitis medicamentosa are directly proportional to the period during which the drug is used, to the frequency of its use, and to the amount of drug administered. However, no studies have been performed to evaluate the effects of various amounts of the vasoconstrictors on the development of rhinitis medicamentosa. Moreover, no in vivo studies have yet been performed to investigate whether benzalkonium chloride in nasal decongestant solutions affects the development of rhinitis medicamentosa. This study shows that rhinitis medicamentosa is a condition of nasal hyperreactivity, mucosal swelling and tolerance induced, or aggravated, by the overuse of topical vasoconstrictors with or without a preservative.