Effect of oxymetazoline nose drops on acute sinusitis in the rabbit.

This investigation was designed to evaluate the effect of the common topical nasal decongestant oxymetazoline hydrochloride on the early local tissue defense in an experimental bacterial infection. For that purpose, a bilateral infection of the maxillary sinus was induced in 14 rabbits. Nose drops (oxymetazoline) were instilled in one nasal cavity, and placebo in the other. After 48 hours, the degree of infection was judged by using a semiquantitative inflammatory score to evaluate histologic preparations of the maxillary sinuses. On the oxymetazoline-treated side, we found a significantly higher degree of inflammation. We conclude that oxymetazoline nose drops, commonly used in acute rhinitis and sinusitis, interfere with the normal defense mechanisms during bacterially induced sinusitis, possibly by a decrease in mucosal blood flow.