Histamine Sensitivity in the Nasal Mucosa during Long-term Use of Xylometazoline in the Doubled Recommended Dose

Abstract

It has been suggested that the severity of rhinitis medicamentosa is dependent on the length of time the drug has been used, on how frequently it is used, and on the amount administered. It has been reported that a 4-week use of oxymetazoline in the recommended dose induced a rebound swelling and an increased histamine sensitivity as a sign of rhinitis medicamentosa and nasal hyperractivity.In order to study the impact of an increased amount of vasoconstrictor on the histamine sensitivity, nine healthy subjects had xylometazoline nasal spray in the doubled recommended dose (1.0 mg/mL; 0.28 mL in each nostril three times daily) for 30 days. After 10 days on the drug the histamine sensitivity was slightly increased, and after another 20 days the sensitivity was significantly increased compared to that before the start of the medication (P < 0.01). When comparing the results from this study with the corresponding ones from the oxymetazoline study, no difference in the histamine sensitivity was seen. One month after the medication was finished three subjects still had an increased sensitivity to histamine.It was concluded that the doubled recommended dose of xylometazoline did not further increase the elevated histamine sensitivity seen following vasoconstrictor used in recommended dose. The results also indicate that the increased histamine sensitivity was not caused by the preservatives. Finally, the subjects achieved a drug-induced non allergic nasal hyperreactivity (NANH) that in some subjects persisted for a long time.