What is the recommended dosage and treatment plan for Fexofenadine (Allegra) in patients with allergic reactions?

Fexofenadine Dosage and Treatment Plan for Allergic Reactions

For allergic reactions, fexofenadine should be administered at 60 mg twice daily or 180 mg once daily for adults and children 12 years and older, and 30 mg twice daily for children 6-11 years of age. 1

Dosage Recommendations 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
  • For patients with decreased renal function: 60 mg once daily 1

• Chronic Idiopathic Urticaria:

  • 60 mg twice daily OR 180 mg once daily with water 1
  • For patients with decreased renal function: 60 mg once daily 1

Children 6-11 Years

• Seasonal Allergic Rhinitis or Chronic Idiopathic Urticaria:
  • 30 mg twice daily with water 1
  • For patients with decreased renal function: 30 mg once daily 1

Treatment Duration and Administration

• For acute allergic reactions: Continue fexofenadine at recommended doses for 2-3 days following the reaction 2
• For seasonal allergic rhinitis: Continue throughout the allergy season 3
• For chronic urticaria: May be used for up to 6 weeks with continued effectiveness 4
• Take with water (no specific food requirements) 1

Clinical Advantages of Fexofenadine

Fexofenadine offers several advantages for allergic reaction management:

• Non-sedating properties: Unlike first-generation antihistamines, fexofenadine does not cause sedation at recommended doses 3
• Rapid onset of action: Relief begins within ≤2 hours after administration 4
• Long duration of action: Suitable for once-daily dosing 4
• Safety profile: Similar to placebo in clinical trials 5
• No cardiac effects: Does not prolong QT interval even at high doses 6

Medication Considerations

When to Discontinue Before Testing

• Stop fexofenadine 3 days before skin prick testing 3

Drug Interactions

• No clinically significant drug interactions have been identified 5
• Unlike terfenadine (its parent compound), fexofenadine does not interact with ketoconazole or erythromycin 5

Special Populations

• Elderly patients: Preferred over first-generation antihistamines due to reduced risk of cognitive impairment 2
• Patients with renal impairment: Use reduced dosing as specified above 1

Efficacy Comparisons

Fexofenadine has been shown to be:

• As effective as loratadine and cetirizine in reducing overall symptoms of seasonal allergic rhinitis 4, 7
• Associated with lower incidence of drowsiness (4%) compared to cetirizine (9%) 7
• Effective for nasal symptoms including sneezing, rhinorrhea, and itchy nose/palate/throat 4

Important Cautions

• For severe allergic reactions or anaphylaxis, epinephrine is the first-line treatment; fexofenadine should only be used as adjunctive therapy after epinephrine administration 2
• Fexofenadine has minimal effect on nasal congestion; consider combination with pseudoephedrine for patients with significant nasal congestion 4
• Avoid concurrent use of alcohol and sedatives, which may enhance CNS effects 3

Fexofenadine's excellent safety profile, non-sedating properties, and once-daily dosing option make it an ideal first-line antihistamine for the management of allergic reactions in both adults and children.