Treatment with xylometazoline (Otrivin) nosedrops over a six-week period.

Twenty healthy subjects were treated with xylometazoline 1 mg/ml for six weeks in order to study the occurrence of tachyphylaxis and rhinitis medicamentosa. Each subject instilled 0.15 ml of xylometaxoline nose-drops into each nostril three times a day. Posterior rhinomanometry was performed before the trial started, after 1, 2, 4 and 6 weeks treatment and 20, 27, 40 and 48 hours after the subject had taken the nose-drops for the last time. With rhinomanometry it was possible in this study to show that the same dose was adequate during the whole six-week period, i.e. no tachyphylaxis was observed. No reactive congestion was observed after the trial was finished.