Recommended Dosing for Allegra (Fexofenadine) and Claritin (Loratadine)
For adults and children 12 years and older, the recommended dose of Allegra (fexofenadine) is 60 mg twice daily or 180 mg once daily, while Claritin (loratadine) is recommended at 10 mg once daily. 1, 2
Allegra (Fexofenadine) Dosing
Adults and Children 12 Years and Older:
- 60 mg twice daily OR 180 mg once daily with water 1
- For patients with decreased renal function, a reduced dose of 60 mg once daily is recommended 1
- Onset of action is within 1-2 hours with a long duration of action, making it suitable for once-daily administration 3
Children 6 to 11 Years:
- 30 mg twice daily with water 1
- For children with decreased renal function, 30 mg once daily is recommended as the starting dose 1
Claritin (Loratadine) Dosing
Adults and Children 12 Years and Older:
Children 2 to 11 Years:
- 5 mg once daily (as syrup formulation) 2
Comparative Efficacy and Side Effects
Efficacy:
- Both medications are effective for treating seasonal allergic rhinitis 3, 4
- Fexofenadine may show a trend toward greater symptom relief at the 180 mg dose compared to lower doses 5
- Some studies suggest loratadine may provide better therapeutic response in certain patients who failed to respond to fexofenadine 6
Side Effects:
- Both medications are second-generation antihistamines with minimal sedative effects at recommended doses 2
- Fexofenadine has no sedative properties even at higher than FDA-approved doses 2
- Loratadine may cause sedation when dosed higher than recommended 2
- The most common side effect for both medications is headache, which occurs at rates similar to placebo 3, 5
Special Considerations
- Unlike first-generation antihistamines, both fexofenadine and loratadine have minimal anticholinergic effects (dry mouth, constipation, urinary retention) 2
- Second-generation antihistamines like fexofenadine and loratadine are generally preferred over first-generation antihistamines due to their favorable side effect profile 2
- Fexofenadine does not inhibit cardiac K+ channels and is not associated with QT interval prolongation 3
- Both medications are suitable for daytime use due to minimal sedation at recommended doses 2
Common Pitfalls to Avoid
- Avoid exceeding recommended doses of loratadine as this may increase sedation 2
- Do not use first-generation antihistamines for routine allergic rhinitis treatment due to their sedative and anticholinergic effects 2
- Be cautious when prescribing antihistamines to elderly patients who may be more sensitive to side effects 2
- Remember that neither medication is particularly effective for nasal congestion; if this is a predominant symptom, consider combination with a decongestant or use of intranasal corticosteroids 2