Sustained use of xylometazoline nasal spray shortens the decongestive response and induces rebound swelling.

Long-term use of topical vasoconstrictors for the nose may result in rhinitis medicamentosa, drug addiction and tachyphylaxis. Some authors also believe that the severity of rebound swelling is proportional to the period during which the drug has been used, the frequency of its administration, and the amount of drug given. It has previously been reported that four-week use of the recommended dose of oxymetazoline induces rebound swelling, a sign of rhinitis medicamentosa. To study the effect of an increased amount of vasoconstrictor on rebound swelling and the decongestive effect of the drug, nine healthy subjects were given xylometazoline nasal spray in double the recommended dose (1.0 mg/ml; 0.28 ml in each nostril thrice daily) for 30 days. After 30 days on xylometazoline, the decongestive effect was the same 1 h after drug administration as before starting the medication. Similarly, after 30 days on xylometazoline, the decongestive effect was less 5 h after drug administration than it was 6 h after drug administration at the start of medication (p < 0.005). After 10 days no rebound swelling was recorded, but after 30 days rebound swelling occurred in eight out of nine subjects (p < 0.05). When comparing the results of this trial with the corresponding results of the oxymetazoline study, no further increase in rebound swelling was found. We conclude that long-term use of xylometazoline nasal spray shortens the decongestive response in healthy volunteers. Moreover, double the recommended dose of xylometazoline did not further increase the rebound swelling seen when using the recommended dose of oxymetazoline.