Azelastine

An antihistamine used to treat allergic rhinitis and conjunctivitis

Chemical structure of Azelastine

Azelastine is a pharmaceutical drug used primarily as an antihistamine for the treatment of allergic rhinitis and allergic conjunctivitis. It is available in various forms, including nasal sprays and eye drops, and is known for its ability to relieve symptoms such as sneezing, itching, and runny nose.

Pharmacology

Azelastine is a selective histamine H1 receptor antagonist. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. Azelastine also exhibits anti-inflammatory properties, which contribute to its effectiveness in treating allergic conditions.

Medical Uses

Azelastine is indicated for the treatment of:

• Allergic rhinitis: Azelastine nasal spray is used to relieve nasal symptoms such as congestion, sneezing, and runny nose associated with seasonal and perennial allergic rhinitis.
• Allergic conjunctivitis: Azelastine eye drops are used to treat itching of the eyes caused by allergic conjunctivitis.

Administration

Azelastine is administered as a nasal spray or eye drops. The nasal spray is typically used twice daily, while the eye drops are used as needed, usually up to four times a day.

Side Effects

Common side effects of azelastine include:

• Bitter taste
• Headache
• Nasal irritation
• Drowsiness

Less common side effects may include:

• Nausea
• Dizziness
• Fatigue

Mechanism of Action

Azelastine works by inhibiting the release of histamine from mast cells and blocking the H1 receptor, preventing histamine from binding and causing allergic symptoms. It also stabilizes mast cells and has anti-inflammatory effects, reducing the overall allergic response.

Chemical Properties

3D structure of Azelastine

Azelastine is chemically classified as a phthalazinone derivative. Its molecular formula is C22H24ClN3O, and it has a molecular weight of 381.9 g/mol. The compound is a white, crystalline powder that is slightly soluble in water.

History

Azelastine was first developed in the 1970s and was approved for medical use in the 1980s. It has since become a widely used medication for the treatment of allergic conditions.

Related Pages

• Antihistamine
• Allergic rhinitis
• Allergic conjunctivitis
• Histamine