Seasonal allergies, hives and itching · Over the counter
Zyrtec (cetirizine) dosage for children
Also sold as Children’s Zyrtec, generic cetirizine
Children’s Zyrtec liquid is 5 mg per 5 mL, given once a day. Children 2 to 5 years take 2.5 mL, 6 to 11 years take 5 mL, and 12 and older take 10 mL. It isn’t approved for children under 2, so check with a doctor at that age. Unlike most medicines on this site, the cetirizine dose goes by age, not weight.
Source: St. Louis Children's Hospital
Zyrtec dose calculator
Zyrtec dosage chart
| Age | Dose (mg) | Liquid 5 mg/5 mL | Chewable 5 mg | Tablet 10 mg |
|---|---|---|---|---|
| 2-5 years | 2.5 mg | 2.5 mL | not used | not used |
| 6-11 years | 5 mg | 5 mL | 1 tablet | not used |
| 12 years and older | 10 mg | 10 mL | 2 tablets | 1 tablet |
- Under 2 years: cetirizine isn’t FDA-approved at this age. Don’t use it unless your child’s doctor tells you to.
Chart: St. Louis Children's Hospital. A hyphen means that product isn’t used at that age.
Why Zyrtec is dosed by age
Cetirizine has a wide safety margin and is given once a day, so the package and hospital dose tables group children by age instead of weight. If your child is very small or very large for their age, ask your pharmacist whether the standard dose fits.
Zyrtec or Benadryl?
Both are antihistamines. Cetirizine lasts up to 24 hours and causes less drowsiness, which makes it the usual choice for seasonal allergies and hives. Diphenhydramine (Benadryl) works faster but wears off in 4 to 6 hours and is more sedating.
When allergy symptoms need a doctor
- Your child is under 2 and has allergy symptoms or hives.
- Symptoms don’t improve after a week of daily use.
- Signs of a severe allergic reaction: trouble breathing, swelling of the face or throat. Call 911.
Common questions
Can I give Zyrtec to my 1-year-old?
Only if your child’s doctor tells you to. It isn’t approved for children under 2.
Is it better to give Zyrtec in the morning or at night?
The standard advice is the morning. If it makes your child drowsy, ask your pharmacist about giving it at bedtime instead.
Can I give Zyrtec and Benadryl together?
Not without a doctor’s advice. Both are antihistamines, and together they increase drowsiness and side effects.
Sources
- Cetirizine (Zyrtec) Dose Table. St. Louis Children's Hospital (Schmitt Pediatric Guidelines). Checked 2026-09-18.
- Drug Facts label on the package. Manufacturer, U.S. OTC Drug Facts. Checked 2026-09-18.