Emedastine

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Emedastine

Emedastine is a second-generation H1 antagonist used in the form of an eye drop for the treatment of allergic conjunctivitis. It functions by blocking the action of histamine, a substance in the body that causes allergic symptoms.

Pharmacology

Emedastine is a relatively selective, second-generation, non-sedating H1 antagonist. Unlike many other antihistamines, it does not penetrate the blood-brain barrier, and therefore, does not cause drowsiness. It works by blocking the action of histamine, which is a substance in the body that causes allergic symptoms. When histamine binds to its receptors on cells, it causes changes within the cells that lead to increased blood flow, inflammation, and allergic symptoms. Emedastine blocks one type of receptor for histamine (the H1 receptor) and thus prevents activation of cells by histamine.

Clinical Use

Emedastine is used in the form of an eye drop for the treatment of the signs and symptoms of allergic conjunctivitis. It is typically used twice daily, with the exact dosage depending on the severity of the condition. The most common side effects are mild eye irritation, burning, or itching. Serious side effects are rare.

Chemistry

Emedastine difumarate, the form of emedastine used in eye drops, is a white, crystalline, water-soluble fine powder. It has a molecular weight of 534.57 and the chemical formula C22H24N2O2•2(C4H4O4).

History

Emedastine was first approved by the Food and Drug Administration (FDA) in 1997 for the treatment of allergic conjunctivitis.

See Also

• Antihistamine
• Conjunctivitis
• Histamine
• H1 antagonist