1. Can Telfast make me sleepy?
It is classed as non-drowsy, but a small number of people may still feel a bit tired. Be careful the first time you take it.
What is Telfast?
Telfast 120mg is a non-drowsy antihistamine used to relieve allergy symptoms by blocking histamine (the chemical your body releases during an allergic reaction).
It can help with:
- Sneezing
- Runny or blocked nose
- Itchy, red, or watery eyes
- Allergy irritation caused by pollen, dust, or pet dander
Active ingredient: Fexofenadine hydrochloride 120mg
Who is Telfast 120mg suitable for?
Suitable for:
- Adults and teenagers aged 12 years and over
Speak to a doctor or pharmacist first if:
- You are allergic to fexofenadine or any ingredient in the tablets
- You have severe kidney problems
- You are pregnant or breastfeeding (ask for advice before using)
How to take Telfast 120mg Tablets
- Take ONE tablet ONCE daily
- Swallow with a glass of water
- Do not take more than 1 tablet in 24 hours
Important information:
- Take it at the same time each day for best results.
- Telfast can be taken with or without food.
How to store Telfast 120mg Tablets
- Store at room temperature
- Keep in the original packaging
- Keep away from heat and moisture
- Keep out of sight and reach of children
- Do not use after the expiry date
Some people may get:
- Headaches
- Dizziness
- Nausea
- Drowsiness
If you get severe symptoms or an allergic reaction (such as swelling, rash, or breathing difficulty), stop taking it and seek urgent medical advice.
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Frequently Asked Questions
2. How long does Telfast take to work?
It usually starts working within about an hour, and lasts up to 24 hours.
3. Can I take more than one tablet a day?
No. Do not take more than 1 tablet in 24 hours unless a medical professional tells you to.
4. What should I do if I miss a dose?
Take it when you remember, unless it’s nearly time for your next dose. Do not take two tablets together.
5. Can I drink alcohol while taking Telfast?
Alcohol may increase dizziness or tiredness in some people, so it’s best to limit alcohol until you know how Telfast affects you.
Our Clinical Authors
This page has been written by a registered UK pharmacist and reviewed by our clinical team to ensure it is accurate, clear and reflects current clinical guidance.
Last medically reviewed: 13 March 2026
Last updated: 13 March 2026