Decongestion effect and rebound swelling of the nasal mucosa during 4-week use of oxymetazoline.

The aim of this study was to investigate whether long-term use of oxymetazoline induces a rebound swelling of the nasal mucosa and whether the decongestion effect is altered during medication. Eight healthy volunteers had oxymetazoline nasal spray (0.5 mg/ml; 0.1 ml in each nostril, three times daily) for 30 days and registrations of the mucosal surface positions were made using rhinostereometry. Compared to the registrations before the start of medication, no rebound swelling was registered after 10 days. After 30 days, however, a rebound swelling was registered in all subjects (p < 0.001). All of them, then, also reported nasal stuffiness. The decongested position of the nasal mucosa after one single dose of oxymetazoline was the same in the whole study. It is concluded that rhinitis medicamentosa develops after a relatively short time on oxymetazoline, even in healthy volunteers, and that the swelling probably is due to a vasodilatation rather than an edema. The study supports the recommendation that the drug should not be used over periods > 10 days.