Antihistamine (Non-Sedating)
Pregnancy: B — generally considered safe
Cetirizine
Brand names: Zirtek, Piriteze
Adult dose
Dose: 10mg once daily
Route: Oral
Frequency: Once daily
Renal impairment: eGFR 30–50 → 5mg OD; eGFR <30 → 5mg every other day.
Paediatric dose
Route: Oral
Frequency: Once or twice daily
6–12 years: 5mg BD or 10mg OD. 2–6 years: 2.5mg BD or 5mg OD. Under 2 years: not recommended.
Clinical pearls
- Preferred over chlorphenamine (first-generation) for daytime use — less sedating
- For chronic urticaria: can dose up to 20–40mg/day (unlicensed) under specialist guidance
- Levocetirizine (active enantiomer) — half the dose for same effect (5mg OD)
- Non-sedating antihistamines do not treat anaphylaxis — use adrenaline first
Contraindications
- Severe renal impairment (eGFR <10)
- Hypersensitivity to hydroxyzine
Side effects
- Drowsiness (less than first-generation)
- Dry mouth
- Headache
- Urinary retention (rare)
Interactions
- Alcohol — increased CNS depression
- Theophylline — slightly reduces cetirizine clearance
Monitoring
- Symptom response
- No routine monitoring required
Reference: BNFc; BNF; EAACI/GA²LEN/EDF Guidelines on Urticaria 2022. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Calculators
Pathways
- Sepsis Screening and Sepsis Six · UK Sepsis Trust; NICE NG51; Surviving Sepsis Campaign 2021
- Unintentional Weight Loss Workup · NICE NG12; BSG
- Chronic Fatigue Workup · NICE NG206; BMJ Best Practice
- Lymphadenopathy Workup · NICE NG12; BMJ Best Practice
- Pre-op Medical Clearance · NICE NG45; ESC 2022
- Secondary Hypertension Workup · NICE NG136; ESH 2023