Is Allegra (fexofenadine) 180 mg a suitable treatment option for a patient with allergic rhinitis?

Yes, Allegra (fexofenadine) 180 mg once daily is an appropriate and FDA-approved treatment for allergic rhinitis in adults and children ≥12 years.

FDA-Approved Indication and Dosing

Fexofenadine 180 mg once daily is specifically FDA-approved for seasonal allergic rhinitis in adults and children 12 years and older, effectively treating sneezing, rhinorrhea, itchy nose/palate/throat, and itchy/watery/red eyes. 1

• The alternative dosing regimen is 60 mg twice daily, which provides equivalent efficacy 1
• For patients with decreased renal function, start with 60 mg once daily 1
• For children 6-11 years, the dose is 30 mg twice daily, not 180 mg 1

Position in Treatment Algorithm

While fexofenadine is effective and appropriate, intranasal corticosteroids remain the most effective first-line monotherapy for allergic rhinitis and should be prioritized when possible 2, 3, 4:

• Second-generation oral antihistamines like fexofenadine are considered effective alternatives when intranasal corticosteroids are not tolerated or preferred 2
• Fexofenadine may be particularly suitable for patients concerned about intranasal administration or those prioritizing rapid onset of action (≤2 hours) 5
• Oral leukotriene receptor antagonists should NOT be used as primary therapy, as they are less effective than both intranasal corticosteroids and antihistamines 2, 3

Evidence of Efficacy

The 180 mg once-daily dose has robust evidence supporting its use:

• Both 120 mg and 180 mg once-daily doses demonstrated significant superiority over placebo in reducing total symptom scores throughout the entire 24-hour dosing interval 6, 7
• Fexofenadine 180 mg showed equivalent efficacy to cetirizine 10 mg once daily in head-to-head trials 6
• A systematic review and meta-analysis of randomized controlled trials confirmed significant reduction in daily reflective total symptom scores (SMD -0.42, p<0.00001) 8
• The 180 mg dose showed a trend toward greater symptom relief compared to 120 mg, though this did not reach statistical significance 7

Safety Profile

Fexofenadine has an excellent safety profile with adverse event rates similar to placebo and significantly less sedation than cetirizine 5, 6:

• No cardiac effects or QT prolongation, even when combined with erythromycin or ketoconazole 5
• Does not cross the blood-brain barrier, resulting in no sedative effects even at doses up to 240 mg/day 5
• Combined incidence of drowsiness/fatigue with fexofenadine (4%) was significantly lower than cetirizine (9%, p=0.02) and similar to placebo (4%) 6
• Headache is the most common adverse event, occurring at rates similar to placebo 5, 7

When to Consider Combination or Alternative Therapy

If fexofenadine 180 mg provides inadequate symptom control:

• Add intranasal corticosteroid for combination therapy, which provides greater efficacy than either agent alone 2, 3
• Consider adding extended-release pseudoephedrine specifically for nasal congestion, as antihistamines have limited effect on this symptom 5, 7
• Refer for allergen immunotherapy if inadequate response to pharmacologic therapy, as this is the only disease-modifying treatment that can prevent long-term recurrence 3

Critical Pitfalls to Avoid

• Do not use first-generation antihistamines (diphenhydramine, hydroxyzine) due to significant sedation, performance impairment, and increased risk of motor vehicle accidents 2
• Avoid intranasal decongestants beyond 3-10 days to prevent rhinitis medicamentosa (rebound congestion) 3
• Do not prescribe 180 mg dose to children under 12 years—use age-appropriate dosing 1
• Ensure patients take fexofenadine with water only, as fruit juices can significantly reduce absorption 1