cetirizine hydrochloride: clinical use

Prescribing considerations

• Assess renal function because cetirizine is predominantly eliminated renally and product-specific adjustment may be necessary.
• Check the formulation's licensed age and excipients, particularly for children or people with carbohydrate intolerances.
• Use caution with urinary-retention risk factors, epilepsy or susceptibility to convulsions.
• Advise about possible somnolence, alcohol and safety-critical activities.
• Antihistamines suppress allergy skin-test responses; coordinate any interruption with the testing service.
• Long-term dry mouth may increase caries risk; reinforce oral hygiene.

Contraindications and cautions

• Hypersensitivity to cetirizine, hydroxyzine, piperazine derivatives or product excipients.
• End-stage or severe renal impairment as defined by the individual product SmPC; wording varies between products.
• Some liquids are unsuitable in specific inherited sugar-intolerance disorders because of excipients such as sorbitol or maltose. Tablets containing lactose are unsuitable in specified galactose or glucose-galactose disorders.

Monitoring

• Renal function where impairment is known or suspected.
• Somnolence, dizziness and impaired performance.
• Urinary retention in susceptible patients.
• Seizure control in people with epilepsy or increased convulsion risk.
• Dry mouth and dental health during prolonged use.
• Breastfed infants for drowsiness, irritability, poor feeding and weight gain.

Clinical pharmacology

Cetirizine is a selective peripheral H1-receptor antagonist and a human metabolite of hydroxyzine. It undergoes little first-pass metabolism, is highly protein-bound and is largely excreted unchanged in urine; renal impairment therefore prolongs exposure.

Formulation and product differences

• Products include film-coated tablets and oral liquids or syrups; minimum licensed ages differ.
• The selected tablet formulation contains lactose.
• Liquids vary in excipients and may contain sorbitol, propylene glycol, parabens, maltose, flavourings or a very small quantity of ethanol.
• Measure liquids with the supplied calibrated device.

Oral solution

Route: Oral

Strengths: 5 mg/5 mL

Tablet

Route: Oral

Strengths: 10 mg