Fexofenadine tablets (Telfast, Allevia, Allegra)
Effective non-drowsy antihistamine for hay fever and hives relief in adults and children.
| Type of medicine | A non-drowsy antihistamine |
|---|---|
| Used for | Seasonal allergic rhinitis (hay fever); chronic urticaria (hives) |
| Also called (UK) | Telfast®; Allevia® |
| Also called (USA) | Allegra®; Mucinex® Allergy; Wal-Fex® |
| Available as | Tablets; oral liquid medicine and melt-in-the-mouth tablet (USA only) |
About fexofenadine
Fexofenadine is a second-generation antihistamine designed to block the effects of histamine, a chemical released by the body during allergic reactions. Unlike first-generation antihistamines, it minimally crosses the blood-brain barrier, reducing the risk of drowsiness, making it suitable for daily use during allergy seasons.
Hay fever, or seasonal allergic rhinitis, affects millions annually, triggered by pollen exposure. Pollen irritates the nasal and ocular linings, prompting histamine release. This leads to inflammation causing sneezing, runny or blocked nose, and itchy, watery eyes known as allergic conjunctivitis. Fexofenadine alleviates these by antagonizing H1 receptors, preventing histamine binding.
Chronic urticaria, or hives, involves itchy welts on the skin lasting over six weeks. Triggers may include allergies, infections, or unknown factors. Fexofenadine eases itching and rash by inhibiting histamine-mediated responses.
Three tablet strengths exist: 30 mg for children aged 6-12 with hay fever; 120 mg for adults with hay fever; 180 mg for adults with chronic urticaria. In the US, 60 mg doses are also common, often taken twice daily. Fexofenadine 120 mg is available over-the-counter in pharmacies for hay fever after pharmacist assessment.
Before taking fexofenadine
Consult a doctor before starting fexofenadine if you have specific health conditions or take other medications. Key precautions include:
- Pregnancy or breastfeeding: Limited data exists; use only if benefits outweigh risks. Inform your doctor if pregnant, planning pregnancy, or breastfeeding.
- Other medicines: Disclose all prescriptions, over-the-counter drugs, herbals, or supplements. Avoid antacids containing aluminium or magnesium within 2 hours of fexofenadine, as they reduce absorption.
- Allergies: Report prior reactions to antihistamines or other drugs.
- Kidney problems: Dose adjustments may be needed for impaired renal function.
- Heart conditions: Though safe, monitor if history of QT prolongation.
Fruit juices like grapefruit, orange, or apple can decrease fexofenadine effectiveness by up to 30%; take with water instead.
How to take fexofenadine
Always follow the patient information leaflet for detailed instructions and side effects. Swallow tablets whole with water, preferably before meals for optimal absorption.
Dosage guidelines
| Condition | Age Group | Dose | Frequency |
|---|---|---|---|
| Seasonal allergic rhinitis (hay fever) | Adults and children 12+ | 120 mg (UK) or 60 mg (US) | Once or twice daily |
| Seasonal allergic rhinitis | Children 6-12 years | 30 mg | Twice daily (morning and evening) |
| Chronic urticaria | Adults and children 12+ | 180 mg | Once daily |
Doses are supported by clinical studies showing peak antihistamine effects at 2-3 hours post-dose, lasting up to 12-24 hours with no tolerance over 28 days. For renal impairment, start with lower doses like 60 mg once daily. Do not exceed recommended amounts.
Getting the most from your treatment
Take fexofenadine only during symptomatic periods for hay fever; discontinue when symptoms resolve unless advised otherwise. Consistent daily timing aids adherence.
Although non-drowsy, 1-10% may experience sedation. Test reactions before driving or operating machinery. Avoid alcohol if drowsy.
Combine with non-drug measures:
- Keep windows closed during high pollen days.
- Use pollen filters in cars.
- Shower after outdoor activities.
- Avoid rubbing eyes or nose.
For urticaria, identify triggers like certain foods or stress.
Possible side effects
Most tolerate fexofenadine well; serious effects are rare (<1/1000). Common side effects (1-10%) include headache, drowsiness, dizziness, nausea.
| Side Effect | Advice |
|---|---|
| Headache | Hydrate; use pharmacist-recommended painkiller. Consult doctor if persistent. |
| Drowsiness/Dizziness | Avoid driving/machinery/alcohol until resolved. |
| Nausea | Eat simple meals; avoid rich/spicy foods. |
| Dry mouth | Chew sugar-free gum; sip water. |
Rare effects: palpitations, rash, insomnia. Seek urgent care for allergic reactions (swelling, breathing difficulty), severe rash, or jaundice. Overdose symptoms include dizziness, dry mouth; seek medical help. Hemodialysis removes little fexofenadine.
Studies confirm no QTc changes even with erythromycin/ketoconazole.
How to store fexofenadine
Store below 25-30°C in original packaging, away from moisture/light/children. Do not use post-expiry. Dispose via pharmacy take-back.
About allergic rhinitis and urticaria
Allergic rhinitis: Affects 10-30% globally, IgE-mediated response to allergens like pollen, dust mites. Symptoms: sneezing, congestion, postnasal drip. Diagnose via history/skin tests.
Urticaria: Acute (<6 weeks) or chronic. Chronic idiopathic urticaria lacks identifiable cause in 50% cases. Treat stepwise: antihistamines first-line.
Frequently Asked Questions (FAQs)
Can I drink alcohol while taking fexofenadine?
Alcohol may amplify drowsiness in sensitive individuals. Limit intake and monitor effects.
How quickly does fexofenadine work?
Onset within 1 hour, peak at 2-3 hours, lasts 12-24 hours.
Is fexofenadine safe for long-term use?
Yes, for chronic conditions under medical supervision; no tolerance develops.
Can children under 6 take fexofenadine?
Not recommended; consult pediatrician for alternatives.
Does fexofenadine interact with fruit juice?
Yes, citrus/apple juices reduce absorption; use water.
References
- Fexofenadine tablets (Telfast, Allevia, Allegra) — Patient.info. 2023. https://patient.info/medicine/fexofenadine-tablets-telfast-allevia-allegra
- ALLEGRA® (fexofenadine hydrochloride) Capsules and Tablets — U.S. Food and Drug Administration (FDA). 2003. https://www.accessdata.fda.gov/drugsatfda_docs/label/2003/20872se8-003,20625se8-010_allegra_lbl.pdf
- Fexofenadine (Allegra): Uses, Side Effects, Interactions — WebMD. 2023. https://www.webmd.com/drugs/2/drug-13823-2204/fexofenadine-oral/fexofenadine-oral/details
- Fexofenadine: Uses, Interactions, Mechanism of Action — DrugBank Online. 2023. https://go.drugbank.com/drugs/DB00950
- Fexofenadine (Allegra): Uses & Side Effects — Cleveland Clinic. 2023. https://my.clevelandclinic.org/health/drugs/20104-fexofenadine-capsules-or-tablets
- Fexofenadine (oral route) – Side effects & dosage — Mayo Clinic. 2023. https://www.mayoclinic.org/drugs-supplements/fexofenadine-oral-route/description/drg-20067082
- Fexofenadine – StatPearls — NCBI Bookshelf, NIH. 2023. https://www.ncbi.nlm.nih.gov/books/NBK556104/
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