What is the recommended dose of Cetirizine (antihistamine) for babies?

Cetirizine Dosage for Babies

The recommended dose of cetirizine for infants 6 to 11 months of age is 0.25 mg/kg twice daily, with a typical daily dose of approximately 4.5 mg. 1

Dosing Guidelines by Age

• Infants 6-11 months:

  • 0.25 mg/kg twice daily 1
  • Safety has been documented in this age group through randomized, double-blind, placebo-controlled studies
  • Mean daily dose in clinical studies: 4.5 ± 0.7 mg

• Children under 6 years:

  • Consultation with a doctor is necessary before administering cetirizine 2
  • For a four-year-old child (as reference): 5 mg (half of the adult dose) once daily 2

Safety Profile in Infants

Cetirizine has been specifically studied in infants with favorable results:

• No significant differences in adverse events between cetirizine and placebo in infants 6-11 months 1
• No prolongation in QT interval observed in cetirizine-treated infants 1
• Trend toward fewer adverse events and sleep-related disturbances in cetirizine group compared to placebo 1

Important Considerations

Renal Function

• Cetirizine is predominantly eliminated by the kidneys with a mean elimination half-life of 8.3 hours 3
• Dose should be halved in moderate renal impairment and avoided in severe renal impairment 2
• Baseline assessment of renal function is recommended before initiating therapy in at-risk patients 2

Administration

• Cetirizine is rapidly absorbed, with significant clinical inhibition of allergic responses occurring within 20 minutes of a single oral dose 3
• Effects persist for 24 hours, though twice-daily dosing may be necessary in very young children 4
• No tolerance to therapeutic effects occurs even after 1 month of daily treatment 3

Pharmacokinetics in Young Children

• In very young children, oral clearance of cetirizine/levocetirizine is more rapid and increases as body weight and age increase 4
• On a mg/kg basis, relatively higher doses may be needed in young children compared to older patients 4

Advantages of Cetirizine in Pediatric Populations

• Second-generation antihistamine with minimal sedative effects at recommended doses 2, 3
• Negligible penetration into the brain, resulting in fewer central nervous system effects 3
• Limited anticholinergic activity compared to first-generation antihistamines 2, 3
• No significant drug interactions with commonly used medications 3
• No cardiac adverse effects documented 3

Common Pitfalls to Avoid

• Avoid exceeding recommended dosages, as overdose can cause drowsiness and sedation (as documented in a case of 12-fold overdose in a four-year-old) 5
• Do not administer to infants younger than 6 months, as safety data is limited in this population
• Remember that cetirizine may cause dry mouth more commonly than placebo, even though it has limited anticholinergic activity 3
• Be aware that twice-daily dosing may be more appropriate for very young children due to faster clearance 4