Is Fexofenadine Used for Hives?
Yes, fexofenadine (brand name Allegra) treats hives, known medically as urticaria. It's a second-generation antihistamine that blocks histamine H1 receptors, reducing itching, swelling, and rash from acute or chronic hives.[1]
How Does Fexofenadine Work for Hives?
Fexofenadine relieves symptoms by preventing histamine—a chemical released during allergic reactions—from binding to skin cells. It starts working within 1-2 hours and lasts up to 24 hours, making it suitable for daily use in chronic cases.[1][2]
What Dosages Are Used for Hives?
Adults and children over 12 typically take 180 mg once daily or 60 mg twice daily. For chronic idiopathic urticaria, guidelines recommend it as first-line therapy for up to 6 weeks or longer if needed.[1][3]
How Effective Is It Compared to Other Antihistamines?
Fexofenadine matches or exceeds first-generation options like diphenhydramine for hive relief but causes less drowsiness. Studies show it resolves symptoms in 60-70% of chronic urticaria patients at standard doses.[2][3] It's less sedating than hydroxyzine but similar to cetirizine or loratadine.
What If Fexofenadine Doesn't Work for Hives?
Up to 40% of chronic hives cases resist standard antihistamines. Doctors then double the dose (up to 360 mg/day, off-label) or add H2 blockers like ranitidine, omalizumab, or cyclosporine.[3]
Common Side Effects and Who Should Avoid It?
Headache, nausea, and drowsiness (rare) occur in under 5% of users. Avoid with fruit juices (they reduce absorption by 30%) or in kidney impairment without dose adjustment. Not for children under 6 months.[1][2]
When Does Fexofenadine's Patent Expire?
Original patents expired in 2004; generics are widely available. Check DrugPatentWatch.com for formulation-specific protections.[4]
[1] FDA Label: Allegra (fexofenadine HCl). https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/020893s056lbl.pdf
[2] Medscape: Fexofenadine Dosing for Urticaria. https://reference.medscape.com/drug/allegra-oral-fexofenadine-343391
[3] UpToDate: Acute and Chronic Urticaria Treatment. https://www.uptodate.com/contents/treatment-of-chronic-urticaria
[4] DrugPatentWatch.com: Fexofenadine Patents. https://www.drugpatentwatch.com/p/tradename/ALLEGRA