What is the lowest effective dose of Fexofenadine (Allegra) for adults?

Lowest Effective Dose of Fexofenadine for Adults

For seasonal allergic rhinitis in adults, the lowest effective dose of fexofenadine is 60 mg twice daily or 120 mg once daily, while chronic idiopathic urticaria requires a higher dose of 180 mg once daily. 1, 2

Dosing by Indication

Seasonal Allergic Rhinitis (SAR)

• Standard effective dose: 120 mg once daily OR 60 mg twice daily 1, 2
• Both regimens demonstrated equivalent efficacy to loratadine 10 mg once daily and cetirizine 10 mg once daily in clinical trials 1
• Onset of symptom relief occurs within ≤2 hours, making it suitable for once-daily administration 1
• The 120 mg once-daily regimen is generally preferred for convenience and compliance 2

Chronic Idiopathic Urticaria (CIU)

• Recommended dose: 180 mg once daily 2, 3
• Lower doses (20 mg, 60 mg, 120 mg twice daily) showed efficacy, but 60 mg twice daily or greater demonstrated optimal effectiveness 3
• The 180 mg once-daily dose was specifically evaluated and proven effective for up to 6 weeks of treatment 1
• All doses ≥60 mg twice daily significantly reduced pruritus, wheal count, and interference with sleep and daily activities compared to placebo 3

Important Clinical Considerations

Safety Profile at Recommended Doses

• Fexofenadine demonstrates a safety profile similar to placebo at therapeutic doses 2
• No sedation occurs even at doses up to 240 mg/day, distinguishing it from cetirizine and first-generation antihistamines 4, 2, 5
• No cardiac toxicity or QTc prolongation observed, even with doses up to 800 mg/day in volunteer studies 6
• No impairment of driving or psychomotor performance at the recommended 60 mg twice daily dose 5

Combination Therapy

• When nasal congestion is prominent in allergic rhinitis, fexofenadine combined with extended-release pseudoephedrine provides complementary activity 1
• Fexofenadine alone produces only small improvements in nasal congestion, which may be inadequate for patients with significant congestion 1

Comparative Effectiveness

• Fexofenadine, loratadine, and desloratadine do not cause sedation at recommended doses, unlike cetirizine which may cause mild drowsiness in 13.7% of patients 4
• Fexofenadine demonstrated greater quality of life improvements compared to loratadine, reaching clinically meaningful differences 1

Practical Prescribing Algorithm

For SAR: Start with 120 mg once daily (or 60 mg twice daily if patient prefers divided dosing) 1, 2

For CIU: Start with 180 mg once daily 2, 3

If inadequate response in SAR with prominent congestion: Add pseudoephedrine rather than increasing fexofenadine dose 1