Background: Azelastine is a topical antihistamine, clinically demonstrated to be effective in allergic rhinitis.
Objective: We evaluated the clinical efficacy and the antiallergic activity of azelastine nasal spray, administered 0.56 mg per day, 0.28 mg per day, or on demand over a 3-month period during natural allergen exposure, in a double-blind, placebo-controlled fashion.
Methods: Thirty patients, sensitized to grass or Parietaria pollen, were allocated to three treatment groups: those receiving the standard dosage (0.14 mg/nostril two times a day), half the dosage (0.07 mg/nostril two times a day), or placebo daily for 3 months. All patients were allowed to take additional doses of azelastine when needed. Evaluation parameters were as follows: clinical symptoms recorded on a diary card, number of additional, on-demand azelastine puffs, nasal inflammatory cell count, intercellular adhesion molecule-1 expression on nasal epithelial cells, and pollen count.
Results: This study showed the following: (1) the half dose (0.28 mg/day) and the standard dose (0.56 mg/day) were equally effective in reducing clinical symptoms (p = NS), although the standard dosage required fewer additional puffs during times of peak pollen counts (p < 0.05); (2) both dosages were able to reduce the allergic inflammation (p < 0.05 vs placebo); and (3) on-demand use achieved acceptable clinical control but did not significantly reduce allergic inflammation.
Conclusion: Continuous treatment was more effective than on-demand use as assessed by both clinical evaluation and antiinflammatory action.