Azelastine hydrochloride, a dual-acting anti-inflammatory ophthalmic solution, for treatment of allergic conjunctivitis

Abstract

Over 50% of patients who seek treatment for allergies present with ocular symptoms. Our current ability to control ocular allergic symptoms is greater than ever before. Newer dual-acting topical eyedrops attack multiple facets of the allergic cascade. Azelastine has antihistaminic effects providing immediate relief, mast cell stabilization providing early-phase intervention, and inhibition of expression and activation of anti-inflammatory mediators which characterize the late phase of the immune reaction. The ophthalmic eyedrop formulation is approved for treatment of allergic conjunctivitis in adults and children aged over 3 years. In clinical trials comparing azelastine with other dual-acting eyedrops, such as levocabastine and olopatadine, azelastine was reported to be slightly less efficacious and to sting briefly upon administration. Even so, many patients experienced the full benefit of symptom relief, and preferred azelastine. As a broad-spectrum drug, azelastine offers many desirable properties for management of ocular allergies. Because it can often produce maximal effect with just twice-daily dosing, azelastine is a particularly good choice for the allergic population in whom minimizing exposure to topical products and preservatives is a key concern.

Keywords: H1 receptor antagonism; allergic conjunctivitis; dual acting anti-inflammatory; inflammatory mediator inhibition; mast cell stabilization.

Figure 1

Structure of azelastine and its major metabolite.

Figure 2

Multiple pathways are responsible for the antiallergic effects of azelastine. The figure summarizes the pathways of action of multiple action antiallergic drugs, which include membrane activation and cell degranulation (early phase reaction) and de-novo synthesis (late-phase reaction). Drugs acting at the membrane level also interfere with the subsequent steps of intracellular Ca²⁺ influx and PTK signal transduction pathway. Copyright © 2009, Lippincott Williams & Wilkins. All rights reserved. Adapted with permission from Lambiase A, Micera A, Bonini S. Multiple action agents and the eye: do they really stabilize mast cells? Curr Opin Allergy Clin Immunol. 2009;9(5):454–465. Abbreviations: lgE, immunoglobulin E; MC, mast cell; NGF, nerve growth factor; PTK, protein-tirosyne kinase; VEGF, vascular endothelial growth factor.

Figure 3

Azelastine topical eye drops cause a sustained decrease in allergic symptoms. Copyright © 2003. Reproduced with permission from Nazarov O, Petzold U, Haase H, Nguyen DT, Ellers-Lenz B, Hermann R. Azelastine eye drops in the treatment of perennial allergic conjunctivitis. Arzneimittelforschung. 2003;53:167–173.