Recommended Dosage of Allegra (Fexofenadine) for Allergic Reactions
The recommended dosage of Allegra (fexofenadine) for treating 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 of age. 1
Dosing Guidelines by Age and Condition
Adults and Children 12 Years and Older:
Seasonal Allergic Rhinitis:
- 60 mg twice daily OR
- 180 mg once daily with water 1
Chronic Idiopathic Urticaria:
- 60 mg twice daily OR
- 180 mg once daily with water 1
Children 6 to 11 Years:
Seasonal Allergic Rhinitis:
- 30 mg twice daily with water 1
Chronic Idiopathic Urticaria:
- 30 mg twice daily with water 1
Special Dosing Considerations
Renal Impairment:
- Adults and Children 12 Years and Older:
- Starting dose: 60 mg once daily 1
- Children 6 to 11 Years:
- Starting dose: 30 mg once daily 1
Pharmacological Properties and Benefits
- Onset of Action: Rapid (≤2 hours) 2
- Duration of Action: Long-lasting, making it suitable for once-daily administration 2
- Sedation Profile: Truly non-sedating with only 1.3% sedation potential, even at high doses 3, 4
- Safety Profile: Similar to placebo in clinical trials 4
- Cognitive Effects: Does not impair driving or psychomotor performance 4
Efficacy Comparisons
- Fexofenadine 120 mg once daily is as effective as cetirizine 10 mg once daily for seasonal allergic rhinitis 5
- Fexofenadine 60 mg twice daily is as effective as loratadine 10 mg once daily for seasonal allergic rhinitis 2
- Both 120 mg and 180 mg once-daily doses provide significant improvement in seasonal allergic rhinitis symptoms compared to placebo 6
Clinical Considerations
- Before starting fexofenadine for allergic reactions, discontinue the medication at least 3 days before any oral food challenge testing to avoid masking symptoms 7
- Fexofenadine is not appropriate as first-line therapy for anaphylaxis, where epinephrine remains the treatment of choice 3
- For milder allergic reactions such as flushing, urticaria, or mild angioedema, fexofenadine can be used effectively 3
Common Side Effects
- Headache is the most frequently reported adverse event, occurring at a similar rate to placebo 4
- The incidence of drowsiness or fatigue with fexofenadine (4%) is significantly lower than with cetirizine (9%) 5
Important Precautions
- Unlike first-generation antihistamines, fexofenadine does not cross the blood-brain barrier, resulting in minimal sedative effects 2
- Fexofenadine does not inhibit cardiac K+ channels and is not associated with QT interval prolongation 2
- No clinically significant drug interactions have been identified 4
Fexofenadine offers effective symptom relief for allergic conditions with a favorable safety profile, making it an excellent first-line option for treating allergic reactions when anaphylaxis is not a concern.