A comparison of the effects of an alpha-agonist, an anti-muscarinic agent and placebo on intranasal histamine challenge in allergic rhinitis.

Autonomic receptors play a part in the physiology and pathology of the nasal mucosa. The effect of an alpha-agonist and an anti-muscarinic agent on histamine-challenge was examined on patients with perennial allergic rhinitis. Nine patients received saline, oxitropium bromide 0.075%, or xylometazoline hydrochloride 0.1% in a double-blind fashion. Sequential challenge with increasing doses of histamine were given and resistance changes, sneezes and volume and content of secretion measured. Histamine challenge produced dose-related increases in nasal resistance (P < 0.0001), lavage fluid volume (P < 0.01) and total protein (P < 0.01). Following xylometazoline, histamine produced little increase in resistance compared with saline and oxitropium bromide (P < 0.0001). The latter reduced the dose-related increase in resistance (P < 0.01) and nasal lavage fluid volume (P = 0.0007) and total protein (P = 0.023) seen with saline. These results confirm the importance of alpha-adrenergic and muscarinic receptors in the human nasal mucosa and suggest mechanisms of action for these drugs in perennial allergic rhinitis.

RCT Entities:   Population Interventions Outcomes