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Second-generation (non-sedating) antihistamine — H1 antagonist

Fexofenadine 120mg / 180mg Tablets

Brand names: Telfast

Fexofenadine tablets are a non-sedating second-generation oral antihistamine used for allergic rhinitis and other allergic symptoms.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 120 mg once daily, taken before a meal
Route: Oral — one 120 mg film-coated tablet
Frequency: Once daily
Verbatim §4.2: 'The recommended dose of fexofenadine hydrochloride for adults is 120 mg once daily taken before a meal. Fexofenadine is a pharmacologically active metabolite of terfenadine.' SCOPE: this is the only adult regimen in the fetched SPC, and it is the 120 mg tablet only. The 180 mg once-daily dose for chronic idiopathic urticaria that this page previously showed is NOT supported by any source in this bundle and is not published; source the 180 mg product's own SPC before restating it. NO MAXIMUM DOSE is stated in this SPC, so no ceiling is published — in particular, the '4× standard dose in refractory chronic urticaria' claim previously on this page has no support in any fetched source. INTERACTION affecting administration (§4.5): 'the administration of an antacid containing aluminium and magnesium hydroxide gels 15 minutes prior to fexofenadine hydrochloride caused a reduction in bioavailability, most likely due to binding in the gastrointestinal tract. It is advisable to leave 2 hours between administration of fexofenadine hydrochloride and aluminium and magnesium hydroxide containing antacids.' Also: 'Fexofenadine is a P-glycoprotein (P-gp) transporter and organic-anion-transporting polypeptide (OATP) substrate... Co-administration of fexofenadine hydrochloride with P-gp inhibitors erythromycin or ketoconazole has been found to result in a 2-3 times increase in the level of fexofenadine in plasma. The changes were not accompanied by any effects on the QT interval and were not associated with any increase in adverse reactions'; apalutamide reduced fexofenadine AUC by 30%; no interaction with omeprazole. NOTE the SPC does not describe fexofenadine as non-sedating: drowsiness is listed in §4.8 as a COMMON adverse reaction alongside headache and dizziness. The fruit-juice interaction previously claimed on this page does not appear anywhere in the fetched SPC.

Paediatric dose

Route: Oral
Frequency: Once daily, taken before a meal (children aged 12 years and over)
Not a per-kg regimen — a fixed dose, so no figure is set for the weight calculator. Verbatim §4.2: 'Children aged 12 years and over — The recommended dose of fexofenadine hydrochloride for children aged 12 years and over is 120 mg one daily taken before a meal.' 'Children under 12 years of age — The efficacy and safety of fexofenadine hydrochloride 120 mg has not been studied in children under 12. In children from 6 to 11 years of age: fexofenadine hydrochloride 30 mg tablet is the appropriate formulation for administration and dosing in this population.' The SPC names the 30 mg tablet as the right formulation for 6–11 year-olds but gives no dose or frequency for that age band in the fetched text, and says nothing at all about children under 6 — so no figure is published for either. The '30 mg twice daily' regimen previously shown on this page is not supported by any fetched source. Verify all under-18 dosing against a children's formulary before prescribing.

Dose adjustments

Renal

No adjustment stated — §4.2, verbatim: 'Studies in special risk groups (elderly, renally or hepatically impaired patients) indicate that it is not necessary to adjust the dose of fexofenadine hydrochloride in these patients.' §4.4 adds a caution: 'As with most new medicinal products there is only limited data in the older people and renally or hepatically impaired patients. Fexofenadine hydrochloride should be administered with care in these special groups.' (The '60 mg once daily if eGFR <80' figure previously on this page contradicts this SPC and is not supported by any fetched source.)

Hepatic

No adjustment stated — the same §4.2 sentence covers hepatic impairment: 'Studies in special risk groups (elderly, renally or hepatically impaired patients) indicate that it is not necessary to adjust the dose of fexofenadine hydrochloride in these patients', with the §4.4 caution to administer with care in this group because data are limited. §4.5 notes 'Fexofenadine does not undergo hepatic biotransformation and therefore will not interact with other medicinal products through hepatic mechanisms.'

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients listed in section 6.1 — §4.3, the only contraindication in this SPC
  • SCOPE NOTE: severe renal impairment is NOT a contraindication in this SPC — §4.2 states no dose adjustment is necessary in renally impaired patients, with a §4.4 caution to administer with care
  • Not a contraindication but a §4.4 warning: 'Patients with a history of or ongoing cardiovascular disease should be warned that, antihistamines as a medicine class, have been associated with the adverse reactions, tachycardia and palpitations'

Side effects

  • Common (≥1/100 to <1/10), §4.8 in adults, 'with an incidence similar to that observed with placebo': headache, drowsiness, dizziness; nausea
  • Uncommon (≥1/1,000 to <1/100): fatigue
  • Post-marketing, frequency not known — immune: hypersensitivity reactions with manifestations such as angioedema, chest tightness, dyspnoea, flushing and systemic anaphylaxis
  • Post-marketing, frequency not known — psychiatric: insomnia, nervousness, sleep disorders or nightmares/excessive dreaming (paroniria)
  • Post-marketing, frequency not known — cardiac: tachycardia, palpitations
  • Post-marketing, frequency not known — gastrointestinal: diarrhoea
  • Post-marketing, frequency not known — skin: rash, urticaria, pruritus; eye: blurred vision

Monitoring

  • No laboratory or routine monitoring is specified anywhere in the fetched SPC
  • Cardiovascular symptoms — §4.4: 'Patients with a history of or ongoing cardiovascular disease should be warned that, antihistamines as a medicine class, have been associated with the adverse reactions, tachycardia and palpitations'
  • Older people and renally or hepatically impaired patients — §4.4: 'there is only limited data' in these groups and fexofenadine 'should be administered with care'
  • Sedation — drowsiness is a COMMON adverse reaction in §4.8, so ask about it rather than assuming the drug is non-sedating in an individual patient

Clinical monograph

How it works

It is a selective peripheral histamine H1-receptor antagonist (the active metabolite of terfenadine) that blocks histamine-mediated allergic responses with little central nervous system penetration.

Prescribing in practice

  • It is substantially less sedating than older antihistamines, making it preferable when drowsiness must be minimised, though individuals may still occasionally be affected.
  • Absorption is reduced by aluminium- and magnesium-containing antacids and by certain fruit juices, which should be separated from the dose.
  • The higher tablet strength is generally reserved for chronic urticaria rather than routine allergic rhinitis, per the SPC.

Monitoring

Routine monitoring is not required; review symptom control and tolerability at follow-up.

Counselling the patient

  • It is usually non-drowsy, but take care driving until you know how it affects you.
  • Avoid taking it at the same time as indigestion remedies or fruit juice.
  • It can be taken regularly during your allergy season for best control.

Evidence & guidelines

Non-sedating antihistamines such as fexofenadine are recommended first-line for allergic rhinitis in UK and international (ARIA) guidance.

Reference: ARIA Guidelines; BSACI Allergic Rhinitis; Telfast SPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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