Azelastine, sold under the brand name Optivar among others, is a H₁ receptor-blocking medication primarily used as a

nasal spray Nasal sprays are used to deliver medications locally in the nasal cavities or systemically. They are used locally for conditions such as nasal congestion and allergic rhinitis. In some situations, the nasal delivery route is preferred for syst ...

to treat

allergic rhinitis Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, ...

(hay fever) and as eye drops for allergic conjunctivitis. Other uses may include

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...

and skin rashes for which it is taken by mouth. Onset of effects is within minutes when used in the eyes and within an hour when used in the nose. Effects last for up to 12 hours. Common side effects include headache, sleepiness, change in taste, and sore throat. It is unclear if use is safe during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that bre ...

. It is a second-generation

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provide ...

and works by blocking the release of a number of inflammatory mediators including

histamine Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Since histamine was discover ...

. Azelastine was patented in 1971 and came into medical use in 1986. It is available as a generic medication in the United States. In 2020, it was the 173rd most commonly prescribed medication in the United States, with more than 3million prescriptions.

Medical uses

Azelastine nasal spray is indicated for the local treatment of the symptoms of seasonal allergic rhinitis and perennial allergic rhinitis, such as rhinorrhea, sneezing and nasal pruritus in people five years of age and older.AHRQ
Allergic Rhinitis and its Impact on Asthma (ARIA) treatment guidelines
In some countries, it is also indicated for the treatment of vasomotor rhinitis in adults and children ≥ 12 years old. Azelastine eye drops are indicated for the local treatment of seasonal and perennial allergic conjunctivitis.

Side effects

Azelastine is safe and well tolerated in both adults and children with

. Bitter taste, headache, nasal burning and

somnolence Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep ...

are the most frequently reported adverse events. US prescribing recommendations warn against the concurrent use of alcohol and/or other central nervous system depressants, but to date there have been no studies to assess the effects of azelastine nasal spray on the CNS in humans. More recent studies have shown similar degrees of

(approx. 2%) compared with placebo treatment. The most common side effect is a bitter taste (about 20% of people). Due to this, the manufacturer has produced another formulation of azelastine with sucralose. The problem of bitter taste may also be reduced by correct application of the nasal spray (i.e. slightly tipping the head forward and not inhaling the medication too deeply), or alternatively using the azelastine/sucralose formulation. In addition, anosmia (loss in the ability to smell) can occur with nasal spray antihistamines (including both formulations of azelastine).

Pharmacology

Pharmacodynamics

Azelastine has a triple mode of action: # Anti-histamine effect, # Mast-cell stabilizing effect and # Anti-inflammatory effect.

Pharmacokinetics

The systemic bioavailability of azelastine is approximately 40% when administered intranasally. Maximum plasma concentrations (Cmax) are observed within 2–3 hours. The

elimination half life Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the bl ...

, steady-state

volume of distribution In pharmacology, the volume of distribution (VD, also known as apparent volume of distribution, literally, ''volume of dilution'') is the theoretical volume that would be necessary to contain the total amount of an administered drug at the same c ...

and plasma clearance are 22 h, 14.5 L/kg and 0.5 L/h/kg respectively (based on intravenous and oral administration data). Approximately 75% of an oral dose is excreted in feces.

Pharmacokinetics Pharmacokinetics (from Ancient Greek ''pharmakon'' "drug" and ''kinetikos'' "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to determining the fate of substances administered ...

of orally administered azelastine is not affected by age, gender, or hepatic impairment.

Metabolism

Azelastine is oxidatively metabolized by the

cytochrome P450 Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various co ...

family into its active metabolite, desmethylazelastine, and two inactive carboxylic acid metabolites.

Chemical properties

The chemical nomenclature of azelastine is (±)-1-(2H)-phthalazinone, 4- 4-chlorophenyl) methyl2-(hexahydro-1-methyl-1H-azepin-4-yl)-monohydrochloride. It is white, almost odorless with a bitter taste.drugs.co
Azelastine
Page accessed June 28, 2015

References

External links

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