Azelastine (azelastine HCl)

Azelastine is a histamine H1-receptor antagonist.

Azelastine is a histamine H1-receptor antagonist. Azelastine, a phthalazinone derivative, is structurally unrelated to other currently available antihistamines and has been characterized a selective H1-receptor antagonist. Although azelastine has been referred to as a second generation (''nonsedating'') antihistamine, adverse CNS effects (e.g., drowsiness) may occur with the drug, particularly at relatively high doses or when administered with CNS depressants (e.g., alcohol).

The desmethyl metabolite also possesses antihistaminic activity. In addition, azelastine inhibits other mediators (e.g., leukotrienes, platelet activating factor (PAF)) involved in allergic reactions. Azelastine may inhibit the accumulation of eosinophils at the site of allergic inflammation and prevent eosinophil degranulation.

Azelastine currently is commercially available in the US as azelastine hydrochloride nasal spray preparation, having a pH of approximately 6.8. When administered intranasally, approximately 40% of a dose reaches systemic circulation.

Azelastine also is commercially available as azelastine hydrochloride ophthalmic solution. Azelastine hydrochloride ophthalmic solution is a sterile solution of the drug in water for injection; the solution contains benzalkonium chloride as a preservative and also contains edetate disodium, hydroxypropyl methylcellulose, sorbitol, and sodium hydroxide. Azelastine hydrochloride ophthalmic solution has a pH of approximately 5-6.5 and an osmolarity of approximately 271-312 mOsml/L.

The American Society of Health-System Pharmacists, Inc. represents that the information provided in the accompanying monograph was formulated with a reasonable standard of care, and in conformity with professional standards in the field. Readers are advised that decisions regarding use of drugs are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and that the information contained in the monograph is provided for informational purposes only. The manufacturer's labeling should be consulted for more detailed information.

The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information contained in the monograph is not a substitute for medical care.

USES: This medication is used to treat itching eyes caused by allergies (allergic conjunctivitis). Azelastine belongs to a class of drugs known as antihistamines. It works by blocking certain natural substances called histamines that are responsible for allergic symptoms.

Do not use this medication to treat redness and irritation due to wearing contact lenses.

Generic name: azelastine HCl
Pronunciation: (AY-ze-LAS-teen)
Drug class: Ophthalmic Antiallergic Agents
Therapeutic class: Ophthalmic Agents

The following indications are listed for Azelastine:

• Allergic Conjunctivitis

Also known as: Allergy Eye Itch, Atopic Conjunctivitis, Itchy Eyes Due To Allergies, Ocular Itching Due To Allergies.