How To Use Telfast

Complete Step‑by‑Step Usage Guide, Dosage Instructions & Safety Information

Key Takeaways: How To Use Telfast

  • Standard dose: Adults and children ≥12 years take one 120 mg tablet once daily.
  • Administration: Swallow whole with water, preferably before a meal. Do not crush or chew.
  • Onset: Relief begins within 1 hour and lasts 24 hours.
  • Antacids: If you take aluminium/magnesium indigestion remedies, leave a 2‑hour gap.
  • Special populations: Use with caution in severe kidney disease; avoid during breastfeeding; pregnancy only if clearly needed.

Telfast (fexofenadine) is a once‑daily antihistamine for hay fever. Using it correctly ensures maximum effectiveness and minimises the risk of side effects. Below we explain exactly how to take it, who can use it, and important safety considerations.

Important Medical Advice

Stop taking Telfast and seek immediate medical help if you experience swelling of the face, lips, tongue or throat, difficulty breathing, flushing, or chest tightness – these could be signs of a serious allergic reaction. Also consult your doctor before use if you have severe kidney or liver disease, heart problems, or are elderly.

How to Take Telfast: Step‑by‑Step Usage Guide

Follow these simple steps each time you take Telfast 120 mg:

  1. Check your dose: Ensure you are taking the correct strength – one 120 mg tablet daily (unless your doctor has advised otherwise).
  2. Prepare a glass of water: Use a full glass of plain water. Do not use fruit juices (they may reduce absorption).
  3. Swallow the tablet whole: Do not crush, chew, or break the tablet. It is designed to release the medicine as you swallow.
  4. Timing with food: For best results, take it before a meal. If you forget, you can take it with food, but avoid taking it at the same time as aluminium/magnesium antacids – leave a 2‑hour gap.
  5. Consistency: Try to take your tablet at the same time each day to maintain steady levels in your body.

🗒️ Patient tip: If you have difficulty swallowing tablets, talk to your pharmacist – Telfast is only available as a film‑coated tablet and should not be crushed.

Dosage Guide

The recommended dose for adults and adolescents aged 12 years and older is one Telfast 120 mg tablet once daily. This provides 24‑hour control of hay fever symptoms.

  • Missed dose: If you forget to take a dose, skip the missed one and take your next dose at the usual time. Do not take a double dose to make up.
  • Overdose: Taking too many tablets may cause dizziness, drowsiness, fatigue, and dry mouth. Contact your doctor or nearest A&E immediately if you suspect an overdose.
  • Renal impairment: In patients with severe kidney problems (creatinine clearance ≤40 mL/min), the starting dose should be 30 mg once daily (a lower strength product is available). Your doctor will advise.
  • Children under 12: This strength is not suitable for children under 12 years. Other fexofenadine formulations (e.g., 30 mg) or different antihistamines may be used – consult your GP.

Who Should Use Telfast

Telfast 120 mg is indicated for:

  • Adults and adolescents aged 12 years and older who suffer from seasonal allergic rhinitis (hay fever) – symptoms include sneezing, itchy/runny/blocked nose, and itchy/red/watery eyes.
  • Individuals who need a non‑sedating antihistamine that does not interfere with daily activities, driving, or work.
  • People who have found other antihistamines ineffective or too sedating.

Always confirm with a pharmacist or doctor that Telfast is appropriate for your specific allergy symptoms.

Who Should NOT Use Telfast

Avoid Telfast 120 mg in the following situations:

  • Allergy: If you are allergic to fexofenadine hydrochloride or any of the tablet ingredients (listed in section 6 of the PIL).
  • Children under 12 years: This strength is not licensed for younger children.
  • Severe renal impairment: Without dose adjustment – a lower strength product should be used under medical supervision.
  • Pregnancy: Unless clearly necessary and prescribed by a doctor (see below).
  • Breastfeeding: Not recommended because fexofenadine passes into breast milk.
  • Rare hereditary problems: The tablets do not contain lactose, but if you have any other intolerance, check the full excipient list.

Should Telfast Be Taken With or Without Food?

The official Patient Information Leaflet advises taking Telfast with water before a meal. Taking it on an empty stomach helps achieve the fastest absorption and symptom relief.

If you have a sensitive stomach, you can take it with food – this may slightly delay absorption but does not reduce the overall effect. However, you must avoid taking it at the same time as indigestion remedies containing aluminium or magnesium (e.g., some antacids). These can reduce the amount of fexofenadine absorbed. Leave at least 2 hours between taking Telfast and such antacids.

Special Conditions: Pregnancy, Breastfeeding & More

Pregnancy

There is limited data on the use of fexofenadine in pregnant women. As a precaution, Telfast should only be used during pregnancy if clearly needed and prescribed by a doctor. Untreated allergic rhinitis can also affect wellbeing, so discuss the risks and benefits with your healthcare provider.

Breastfeeding

Fexofenadine passes into breast milk in small amounts. It is not recommended during breastfeeding unless your doctor considers it essential. An alternative antihistamine with a more established safety profile may be preferred.

Renal impairment

In patients with mild to moderate kidney problems, no dose adjustment is usually needed. However, in severe renal impairment (creatinine clearance ≤40 mL/min), peak levels increase – a lower dose (30 mg once daily) is recommended. Your doctor will prescribe the appropriate strength.

Hepatic impairment

Fexofenadine is minimally metabolised in the liver, so no dosage adjustment is required in liver disease.

Elderly

Clinical studies show that the safety profile in older people is similar to that in younger adults. Nevertheless, as with any medicine, use with caution, especially if there is reduced kidney function.

Telfast FAQs

There is no known direct interaction, but alcohol may worsen dizziness or drowsiness in sensitive individuals. It's wise to limit alcohol until you know how Telfast affects you.

Yes, Telfast is safe for long‑term daily use during the hay fever season. If symptoms persist beyond seasonal periods, consult your doctor to rule out other causes.

Combining antihistamines is not usually recommended. However, Telfast may be used alongside nasal sprays (e.g., corticosteroids) or eye drops. Always check with a pharmacist before combining.

If you forget to take your tablet, skip the missed dose and take the next one at the usual time. Do not take two doses to make up for a forgotten one.

Telfast is non‑sedating and unlikely to impair driving. However, a small number of people may experience drowsiness. If you feel sleepy, do not drive or operate machinery.

Need Telfast for Hay Fever?

If you're sure Telfast is right for you, our UK‑registered doctors and pharmacists can help with a quick online consultation. Get safe, discreet advice and next‑day delivery if prescribed.

Secure Prescription & Next‑Day Delivery

MHRA‑compliant | GPhC‑registered pharmacy | Discreet packaging | UK‑registered doctors

Start Allergy Consultation
Nabeel M. - Medical Content Manager at Chemist Doctor
Authored byNabeel M.

Medical Content Manager

Nabeel is a co‑founder and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up‑to‑date.

Medical Doctor

Dr. Feroz is a GMC‑registered doctor and a medical reviewer at Chemist Doctor. He oversees acute condition and urgent care guidance.

Usman Mir - Superintendent Pharmacist
Approved byUsman Mir

Medical Director

Usman is a co‑founder and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.

Review Date: 12 March 2026

Next Review: 12 September 2026

Published on: 12 March 2026

Last Updated: 12 March 2026