Autonomic dysfunction in perennial vasomotor rhinitis and the effect of mequitazine

Thirty patients with perennial vasomotor rhinitis were submitted to pharmacological tests to assess the autonomic responsiveness of extra-nasal and intra-nasal receptors to isoprenaline and phenylephrine by infusion, and to evaluate the effect of 14-days' treatment with mequitazine (5 mg twice daily) and placebo on clinical symptoms and on autonomic sensitivity. Isoprenaline induced a similar tachycardia in all patients, more pronounced than that observed in normal subjects, at the different times of testing, and also an increase in nasal resistance. With phenylephrine, marked bradycardia was observed, reflecting high vagal baroreflex sensitivity, and a transient decrease in nasal resistance was obtained. Mequitazine improved significantly the clinical symptoms but did not modify the autonomic receptivity. It is suggested that in patients with vasomotor rhinitis an autonomic dysfunction may play a role in a predisposing factor in nasal hyperreactivity with non-specific histamine release.