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Non-sedating H1 antihistamine Pregnancy: Should not be used during pregnancy unless on the advice of a doctor; no adequate data in pregnant women (UK SPC §4.6)

Fexofenadine hydrochloride

Brand names: Telfast, Allevia

Fexofenadine is a non-sedating (second-generation) antihistamine used for allergic rhinitis and chronic urticaria.

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
Route: Oral
Frequency: Once daily, taken before a meal
UK SPC (120 mg film-coated tablet). Adults: 120 mg once daily taken before a meal. Children aged 12 years and over: 120 mg once daily taken before a meal. Children under 12 years: efficacy and safety not studied; this 120 mg strength should not be used. In children 6 to 11 years, a fexofenadine hydrochloride 30 mg tablet is the appropriate formulation. No dose adjustment necessary in elderly or renally/hepatically impaired patients. Clinician to verify paediatric dosing against a children's formulary.

Dose adjustments

Renal

No dose adjustment necessary in renally impaired patients (UK SPC §4.2)

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Directions do not divide, crush, chew or dissolve the tablet; swallow tablet whole adults and children 12 years of age and over take 1 tablet with a glass of water every 12 hours on an empty stomach; do not take more than 2 tablets in 24 hours children under 12 years of age do not use adults 65 years of age and older ask a doctor consumers with kidney disease ask a doctor

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2018-05-31. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients

Side effects

  • Headache
  • Drowsiness
  • Dizziness
  • Nausea
  • Fatigue

Interactions

  • Erythromycin or ketoconazole (P-gp inhibitors) — 2-3 fold increase in plasma fexofenadine, without QT effect
  • Apalutamide (weak P-gp inducer) — approx 30% decrease in fexofenadine AUC
  • Aluminium/magnesium hydroxide antacids — reduced bioavailability; leave 2 hours between doses

Clinical monograph

How it works

It is a selective peripheral histamine H1-receptor antagonist with minimal central penetration, so it is essentially non-sedating.

Prescribing in practice

  • It is among the least sedating antihistamines.
  • Absorption is reduced by some fruit juices and by aluminium/magnesium antacids — separate their timing.
  • It is not a treatment for anaphylaxis, which requires adrenaline and emergency care.

Monitoring

Review symptom control; no routine monitoring.

Counselling the patient

  • It is non-drowsy for most people.
  • Avoid taking it at the same time as fruit juice or indigestion remedies.
  • It does not treat severe allergic reactions, which need emergency care.

Evidence & guidelines

A non-sedating antihistamine for allergic rhinitis and chronic urticaria.

Reference: BSACI urticaria guideline; 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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