Oxymetazoline nasal spray three times daily for four weeks in normal subjects is not associated with rebound congestion or tachyphylaxis.

Topical decongestants are available over the counter and provide rapid relief of nasal obstruction for conditions of short duration, for example the common cold. Manufacturers' recommendations are that topical decongestants should not be used regularly for more than 1 week in view of the risk of rebound mucosal hyperaemia with persistent nasal obstruction and refractoriness to further effects of decongestants. For this reason we performed a randomised double-blind placebo-controlled trial in 30 normal adult subjects with 0.05% oxymetazoline nasal spray 2 sprays (0.1 ml/spray) to each nostril 3 times daily over an extended period of 4 weeks. Degree of nasal blockage was assessed before and after 4 weeks treatment and for 2 weeks following discontinuation of treatment. Outcome measures included diary symptom scores and measurements of nasal peak inspiratory flow, airway resistance (using posterior active rhinomanometry) and volume (using acoustic rhinometry). Nasal patency was assessed at baseline and 15 minutes after oxymetazoline challenge at each clinic visit. Results demonstrated no significant increases in subjective nasal blockage throughout the 6 weeks study period in either oxymetazoline- or placebo-treated subjects. No significant differences were observed between groups for baseline measurements of nasal peak inspiratory flow, airway resistance or volume at each clinic visit. A highly significant decongestant effect of oxymetazoline was observed at each clinic visit with changes in all 3 measurements for both treatment groups, again with no significant differences between groups. In summary, in normal subjects, we identified no significant nasal blockage or impaired decongestant response to oxymetazoline following 4 weeks treatment with oxymetazoline compared to matched placebo nasal spray.