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Second-generation (non-sedating) antihistamine — H1 antagonist Pregnancy: Use with caution — limited data; loratadine has more human safety data and is generally preferred.

Fexofenadine 120mg / 180mg Tablets

Brand names: Telfast

Adult dose

Dose: 120 mg once daily (seasonal allergic rhinitis) or 180 mg once daily (chronic urticaria)
Route: Oral
Frequency: Once daily
Max: 180 mg/day
Seasonal allergic rhinitis: 120 mg once daily. Chronic idiopathic urticaria: 180 mg once daily. Truly non-sedating (does not cross blood-brain barrier). Take on empty stomach — food and fruit juices reduce absorption. Avoid grapefruit, orange, and apple juice within 4 hours.

Paediatric dose

Route: Oral
Frequency: Once daily
Max: 120 mg/day
6–11 years: 30 mg twice daily (suspension if available). 12 years and over: adult dose (120 mg OD for AR; 180 mg OD for urticaria). Paediatric suspension not widely available in UK — check unlicensed availability.

Dose adjustments

Renal

Starting dose of 60 mg once daily if eGFR <80 mL/min/1.73m².

Hepatic

No specific dose adjustment recommended.

Clinical pearls

  • Truly non-sedating — no CNS penetration; does not affect driving or cognitive function
  • Preferred over cetirizine/loratadine for patients where drowsiness is a significant concern (pilots, shift workers)
  • Must be taken with water — fruit juices significantly reduce absorption
  • BSACI guidelines allow up to 4× standard dose in refractory chronic urticaria under specialist supervision
  • Active metabolite of terfenadine (now withdrawn) — fexofenadine lacks terfenadine's cardiac QTc risk

Contraindications

  • Hypersensitivity to fexofenadine or terfenadine
  • Severe renal impairment (use reduced dose)

Side effects

  • Headache
  • Nausea
  • Dizziness (rare)
  • Drowsiness (much less than first-generation antihistamines)
  • Fatigue

Interactions

  • Antacids (aluminium/magnesium hydroxide) — reduce fexofenadine absorption; separate by 2 hours
  • Fruit juices (grapefruit, orange, apple) — reduce bioavailability by up to 36%; take with water
  • Erythromycin and ketoconazole — increase fexofenadine plasma levels (clinical significance uncertain)

Monitoring

  • Symptom response (TNSS score for rhinitis)
  • Drowsiness assessment

Reference: BNFc; BNF; ARIA Guidelines; BSACI Allergic Rhinitis; Telfast SPC. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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