Fexofenadine (Allegra) Dosing for Allergic Reactions
The recommended dose of fexofenadine for allergic reactions is 60 mg twice daily or 180 mg once daily with water for adults and children 12 years and older, and 30 mg twice daily for children 6-11 years. 1
Adult and Adolescent Dosing (12 years and older)
- For seasonal allergic rhinitis: 60 mg twice daily or 180 mg once daily 1
- For chronic idiopathic urticaria: 60 mg twice daily or 180 mg once daily 1
- Fexofenadine is a second-generation antihistamine that is non-sedating at recommended doses, making it preferable over first-generation antihistamines for daytime use 2
- Patients with decreased renal function should start with 60 mg once daily 1
Pediatric Dosing (6-11 years)
- For both seasonal allergic rhinitis and chronic idiopathic urticaria: 30 mg twice daily 1
- Children with decreased renal function should start with 30 mg once daily 1
Clinical Advantages of Fexofenadine
- Fexofenadine is one of several second-generation antihistamines that does not cause sedation at recommended doses, along with loratadine and desloratadine 2
- Unlike cetirizine and intranasal azelastine which may cause sedation at recommended doses, fexofenadine maintains its non-sedating profile even at doses higher than recommended 2, 3
- Fexofenadine has a safety profile similar to placebo in clinical trials for seasonal allergic rhinitis and chronic idiopathic urticaria 3
- It does not impair driving or psychomotor performance, which is an important consideration for patients who need to remain alert 3
Special Considerations
- Fexofenadine has been shown to be effective in reducing systemic reactions when used as premedication before aeroallergen rush immunotherapy 2
- For patients undergoing oral food challenges, fexofenadine should be discontinued 3 days before the procedure to avoid masking symptoms 2
- For elderly patients with generalized pruritus without visible skin signs, fexofenadine 180 mg or loratadine 10 mg are recommended non-sedative options 2
- Sedative antihistamines should be avoided in elderly patients due to increased risk of adverse effects 2
Pharmacokinetics
- Fexofenadine is rapidly absorbed, reaching peak concentrations in 0.83 to 1.33 hours 4
- It shows dose-proportional pharmacokinetics over a wide dosing range 4
- The drug is well tolerated at oral doses up to 11 times the recommended therapeutic dose 4
Potential Side Effects
- The most common adverse events are headache, throat irritation, viral infection, nausea, dysmenorrhea, drowsiness, dyspepsia and fatigue, but these occur at rates similar to placebo 5
- Unlike some other antihistamines, fexofenadine does not cause cardiac QT interval prolongation even at high doses 5
Fexofenadine's non-sedating properties and excellent safety profile make it an optimal choice for many patients requiring antihistamine therapy for allergic conditions.