What are the recommended anti-allergics (antihistamines) for treating allergic rhinitis?

Recommended Antihistamines for Allergic Rhinitis

Second-generation antihistamines are generally preferred over first-generation antihistamines for the treatment of allergic rhinitis due to their improved safety profile and reduced sedative effects. 1, 2

Oral Antihistamine Options

• Second-generation antihistamines effectively reduce rhinorrhea, sneezing, and itching associated with allergic rhinitis but have limited effect on nasal congestion 1, 3
• Among second-generation antihistamines, there are important differences in sedative properties:
  • Fexofenadine, loratadine, and desloratadine do not cause sedation at recommended doses 1, 2
  • Loratadine and desloratadine may cause sedation at doses exceeding the recommended dose 1, 2
  • Cetirizine may cause sedation even at recommended doses 1, 2
• Fexofenadine maintains its non-sedating properties even at higher than FDA-approved doses, making it truly non-sedating 2
• Continuous treatment for seasonal or perennial allergic rhinitis is more effective than intermittent use 1, 2

Intranasal Antihistamine Options

• Intranasal antihistamines may be considered for use as first-line treatment for both allergic and nonallergic rhinitis 1
• Intranasal antihistamines are efficacious and equal to or superior to oral second-generation antihistamines for treatment of seasonal allergic rhinitis 1
• Intranasal antihistamines have been associated with a clinically significant effect on nasal congestion, unlike oral antihistamines 1
• Currently available intranasal antihistamines (like azelastine) have been associated with sedation and can inhibit skin test reactions due to systemic absorption 1, 2
• Intranasal antihistamines are generally less effective than intranasal corticosteroids for treatment of allergic rhinitis 1

Comparative Efficacy

• No single second-generation antihistamine has been conclusively found to achieve superior overall response rates 1
• Cetirizine has demonstrated a shorter onset of action (59 minutes to 2 hours) compared to loratadine (1 hour 42 minutes or longer) in direct comparisons 4
• Fexofenadine has shown an onset of action within 60 minutes 4
• In children 2-6 years old with perennial allergic rhinitis, cetirizine was more effective than loratadine in relieving rhinorrhea, sneezing, nasal obstruction, and nasal pruritus 5

Special Populations

• First-generation antihistamines should be avoided in children under 6 years due to safety concerns 2
• Older adults are more sensitive to the psychomotor impairment from antihistamines, making second-generation options strongly preferred 2, 6
• For patients with both allergic rhinitis and asthma, montelukast (a leukotriene receptor antagonist) may be considered as it is approved for both conditions 1, 7

Common Pitfalls to Avoid

• First-generation antihistamines (diphenhydramine, chlorpheniramine, brompheniramine) can cause performance impairment even when patients don't feel drowsy 2, 6
• Don't assume all second-generation antihistamines have the same sedation profile; there are important differences 1, 2
• Be cautious with standard doses of loratadine or desloratadine in patients with low body mass, as they may experience sedation due to higher relative dosing 2
• Intranasal corticosteroids are more effective than antihistamines for controlling the full spectrum of allergic rhinitis symptoms, especially when nasal congestion is prominent 1, 2

Treatment Algorithm

1. For mild intermittent or mild persistent allergic rhinitis:

   • Start with a second-generation oral antihistamine (fexofenadine, loratadine, desloratadine) or intranasal antihistamine (azelastine) 1, 3
   • Choose fexofenadine if sedation is a significant concern 2

2. For moderate to severe persistent allergic rhinitis:

   • Use an intranasal corticosteroid either alone or in combination with an intranasal antihistamine 1, 3

3. For nonallergic rhinitis:

   • Use an intranasal antihistamine as monotherapy or in combination with an intranasal corticosteroid 3

4. For patients with both allergic rhinitis and asthma:

   • Consider montelukast as it is approved for both conditions 1, 7