Overview
Fexofenadine is a second-generation antihistamine used to treat allergic conditions. It is a selective peripheral H1-receptor antagonist that does not cross the blood-brain barrier significantly, resulting in minimal sedation compared to first-generation antihistamines. It is effective for seasonal allergic rhinitis, chronic idiopathic urticaria, and other allergic conditions.
Mechanism of Action
Fexofenadine is a selective peripheral H1-receptor antagonist. It competitively inhibits histamine binding at H1-receptors in blood vessels, gastrointestinal tract, and bronchial smooth muscle, preventing histamine-mediated allergic responses. Unlike first-generation antihistamines, it has minimal affinity for central nervous system receptors, resulting in reduced sedation.
Indications
- Seasonal allergic rhinitis (hay fever)
- Chronic idiopathic urticaria (hives)
Dosage
Adults and children 12+ years: 60 mg twice daily or 180 mg once daily for allergic rhinitis; 60 mg twice daily for chronic urticaria. Children 6-11 years: 30 mg twice daily. Available as tablets (30 mg, 60 mg, 180 mg) and oral suspension. Take on empty stomach as food may reduce absorption.
Contraindications
- Hypersensitivity to fexofenadine or any component of the formulation
Side Effects
- Headache
- Drowsiness
- Nausea
- Dyspepsia
- Fatigue
- Dizziness
- Dry mouth
Interactions
- Antacids containing aluminum or magnesium may decrease absorption (separate administration by 2 hours)
- Erythromycin and ketoconazole may increase fexofenadine plasma concentrations
- Fruit juices (apple, orange, grapefruit) may decrease absorption