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Second-generation (non-drowsy) antihistamine (H1 receptor antagonist)

Fexofenadine: uses, side effects & precautions

Also known as Allegra, Telfast, Fexidine.

Esta información es solo orientativa de carácter general y no constituye un consejo médico. Consulta siempre a un profesional sanitario cualificado para cualquier asunto médico personal. En caso de emergencia, llama al número de emergencias de tu zona.

What it is used for

  • Hay fever (allergic rhinitis)
  • Sneezing, runny nose, itchy or watery eyes
  • Chronic hives (urticaria) and itching
  • Allergy symptoms from pollen, dust, or animals

How it works

Fexofenadine blocks histamine, the chemical released during allergic reactions, reducing symptoms such as sneezing, itching, and watering without usually causing drowsiness.

How it is taken

Comes as tablets and, in some places, a liquid. It is taken by mouth. It is often recommended to take it with water rather than fruit juice. Follow your doctor's, pharmacist's, or the label's instructions exactly, and do not exceed the recommended amount.

No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.

Common side effects

  • Headache
  • Drowsiness (uncommon)
  • Dizziness
  • Nausea
  • Dry mouth

Serious effects — get help

  • Signs of a severe allergic reaction (facial or throat swelling, difficulty breathing)
  • Fast or irregular heartbeat
  • Chest tightness

If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.

Interactions to watch

  • Antacids containing aluminium or magnesium (can reduce absorption if taken close together)
  • Fruit juices such as apple, orange, or grapefruit (may lower how much is absorbed)
  • Other sedating medicines
  • Certain medicines affecting the heart rhythm

Who should take care

  • Tell your clinician if you are pregnant, planning pregnancy, or breastfeeding
  • Caution with kidney problems
  • Avoid if allergic to fexofenadine
  • Take with water and separate from fruit juice or antacids as advised

Frequently asked questions

Why should I take fexofenadine with water and not juice?
Fruit juices can reduce how much of the medicine your body absorbs, so it may work less well. Plain water is best.
Does fexofenadine cause drowsiness?
It is one of the least sedating antihistamines, but a small number of people still feel mild drowsiness.
Can I take fexofenadine with an antacid?
Leave a gap between them, because antacids can reduce absorption. Ask a pharmacist about timing.
How quickly does fexofenadine work?
It usually begins to relieve symptoms within an hour or two.
Is Fexofenadine safe to take?
For most people it is safe when taken exactly as a doctor or pharmacist advises and as printed on the label. Tell your clinician about your other medicines and health conditions, and seek urgent care for any serious reaction.

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