Topical active H1-antihistamines and their effect on nasal airway resistance.

The introduction of a topically active H1-antihistamine nasal spray Azelastine, has given an extra dimension in the management of allergic rhinitis. The drug acts rapidly and avoids the systemic adverse effects of antihistimines. An objective prospective study was performed to detect the effect of Azelastine nasal spray on nasal airway resistance. Twelve healthy adult volunteers with no rhinological problems were included in the study. Nasal cavities were sprayed with 280 micrograms (two puffs) of Azelastine nasal spray and the nasal airway resistance was measured with anterior rhinomanometry at intervals of 30 minutes for up to two hours. Our study has shown a statistically significant increase in the total nasal airway resistance following the use of Azelastine nasal spray in the absence of a subjective change in nasal airway resistance. There are substances when inhaled which can cause subjective improvement in nasal airway patency without changing the measured nasal airway resistance. However this medication gives no subjective change in nasal airway patency in spite of increasing nasal airway resistance.