Fexofenadine

Brand/Trade Names: Allegra, Telfast

Description: Fexofenadine is a second-generation, long lasting H1-receptor antagonist (antihistamine) which has a selective and peripheral H1-antagonist action. Histamine is a chemical that causes many of the signs that are part of allergic reactions, for example, swelling of tissues. Histamine is released from histamine-storing cells (mast cells) and attaches to other cells that have receptors for histamine. The attachment of the histamine to the receptors causes the cell to be “activated,” releasing other chemicals which produce the effects that we associate with allergy. Fexofenadine blocks one type of receptor for histamine (the H1 receptor) and thus prevents activation of cells by histamine. Unlike most other antihistamines, fexofenadine does not enter the brain from the blood and, therefore, does not cause drowsiness. Fexofenadine lacks the cardiotoxic potential, since it does not block the potassium channel involved in repolarization of cardiac cells.
Like other H1-blockers, fexofenadine competes with free histamine for binding at H1-receptors in the GI tract, large blood vessels, and bronchial smooth muscle. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Fexofenadine exhibits no anticholinergic, alpha1-adrenergic or beta-adrenergic-receptor blocking effects.

Uses: Fexofenadine is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms.

Fexofenadine Structural Formula


Additional Information Data And Resources:
Allegra Prescribing Information
Allegra-D Monograph