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Non-sedating H1 antihistamine Pregnancy: Prospectively collected data do not suggest maternal or foetal/embryonic toxicity above background rates; animal studies show no harmful effects. Caution should be exercised when prescribing to pregnant women. Cetirizine passes into breast milk (25-90% of plasma concentrations) — a risk of side effects in breastfed infants cannot be excluded; caution in lactating women.

Cetirizine hydrochloride

Brand names: Zirtek, Piriteze

Cetirizine is a non-sedating (second-generation) antihistamine used for allergic rhinitis, urticaria and other allergic conditions.

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: 10 mg (1 tablet)
Route: oral
Frequency: once daily
10 mg once daily (1 tablet), swallowed with a glass of liquid. Elderly: no dose reduction needed provided renal function is normal. PAEDIATRIC (UK SPC): the tablet formulation should not be used in children under 6 years (does not allow dose adjustment) — use a paediatric formulation; children 6-12 years 5 mg twice daily (half a tablet twice daily); adolescents over 12 years 10 mg once daily.

Dose adjustments

Renal

Adjust dosing interval by renal function. Normal (eGFR >=90) and mildly decreased (60-90): 10 mg once daily. Moderately decreased (30-60): 5 mg once daily. Severely decreased (15-30, not on dialysis): 5 mg once every 2 days. End-stage renal disease (<15) requiring dialysis: contraindicated. In patients with combined hepatic and renal impairment, adjust dose as for renal impairment.

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 may be taken with or without water chew or crush tablets completely before swallowing children 2 to under 6 years of age Chew and swallow 1 tablet (2.5 mg) once daily; If needed, dose can be increased to a maximum of 2 tablets (5 mg) once daily or 1 tablet (2.5 mg) every 12 hours. Do not give more than 2 tablets (5 mg) in 24 hours. adults and children 6 years and over Chew and swallow 2 tablets (5 mg) or 4 tablets (10 mg) once daily depending upon severity of symptoms; do not take more than 4 tablets (10 mg) in 24 hours. adults 65 years and over Chew and swallow 2 tablets (5 mg) once daily; do not take more than 2 tablets (5 mg) in 24 hours. children under 2 years of age ask a …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-04-07. 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, to any of the excipients, to hydroxyzine or to any piperazine derivatives
  • End-stage renal disease with eGFR below 15 ml/min

Side effects

  • Somnolence
  • Fatigue
  • Dizziness
  • Headache
  • Dry mouth

Interactions

  • No clinically significant interactions expected (pharmacokinetic/pharmacodynamic/tolerance profile)
  • No significant interaction reported with pseudoephedrine or theophylline (400 mg/day)
  • Alcohol / other CNS depressants — concurrent use may cause additional reductions in alertness and impairment of performance (cetirizine does not potentiate alcohol at 0.5 g/L)

Clinical monograph

How it works

It is a selective peripheral histamine H1-receptor antagonist with little central penetration.

Prescribing in practice

  • It is much less sedating than older antihistamines, though mild drowsiness can occur.
  • Reduce the dose in significant renal impairment.
  • 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 usually non-drowsy but can occasionally cause mild sedation.
  • It does not treat severe allergic reactions, which need emergency care.

Evidence & guidelines

A first-line non-sedating antihistamine for allergic rhinitis and urticaria.

Reference: 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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Featured in these MRCEM clinical pathways

Cetirizine hydrochloride is a core drug in the following exam-focused workups on our sister siteReviseMRCEM.

MRCEM Primary / Intermediate / OSCE candidates: each pathway includes exam-style questions, RCEM/NICE citations, and FAQ summaries.