Zyrtec and Claritin Dosage for Kids by Age
Cetirizine (Children's Zyrtec) and loratadine (Children's Claritin) are once-a-day antihistamines. They treat sneezing, runny nose, itchy eyes, and hives with much less drowsiness than diphenhydramine (Benadryl). Unlike fever medicines, their labels dose by age, not weight.
Dosage by age (from the product labels)
Both children's liquids contain 5 mg per 5 mL. Use the dosing cup or syringe that comes in the box.
| Age | Cetirizine (Zyrtec) | Loratadine (Claritin) |
|---|---|---|
| Under 2 years | Ask your doctor | Ask your doctor |
| 2 to 5 years | 2.5 mL (2.5 mg) once daily. May increase to 5 mL once daily, or 2.5 mL every 12 hours. Max 5 mL in 24 hours. | 5 mL (5 mg) once daily. Max 5 mL in 24 hours. |
| 6 years to adult | 5 mL or 10 mL (5 to 10 mg) once daily depending on symptoms. Max 10 mL in 24 hours. | 10 mL (10 mg) once daily. Max 10 mL in 24 hours. |
Chewable and dissolving tablets come in different strengths (for example 2.5 mg, 5 mg, or 10 mg). Read the label on your package for the matching dose. Children with liver or kidney disease should ask a doctor before using either medicine.
What about weight-based dosing?
Parents often search for a "loratadine dose calculator" or a cetirizine dose in mg per kg. The approved labels for both medicines use age bands, and the doses are low and fixed, so weight-based math rarely changes the answer for a healthy child. Our pediatric dose calculator uses these age bands for antihistamines and shows the starting cetirizine dose. Under 2, ask your doctor. If your child is very small or very large for their age, call us and we will tell you which dose to use.
Zyrtec vs. Claritin for kids
- Speed: cetirizine usually starts working within an hour; loratadine can take a little longer.
- Drowsiness: loratadine is the least sedating. Cetirizine makes some children mildly sleepy, so some families give it at bedtime.
- Hives: both help. For hives that keep returning, call us so we can look for a cause and adjust the plan.
- Switching: if one medicine does not help after 1 to 2 weeks of daily use, the other is a reasonable next try. Do not give both on the same day unless we recommend it.
When allergy medicine is not enough
For a child with constant congestion, a steroid nose spray often works better than an oral antihistamine. Children who wheeze, cough at night, or have symptoms most of the year may have asthma or a specific trigger worth finding. Our guide to allergy testing for kids explains when testing helps.
Antihistamines do not treat anaphylaxis. Call 911 and use epinephrine if your child:
- Has trouble breathing, wheezing, or throat tightness
- Has swelling of the lips, tongue, or face
- Vomits repeatedly or seems faint after a food, medicine, or sting
Allergy Symptoms That Keep Coming Back?
We can confirm the right dose, sort out allergies from frequent colds, and build a plan for allergy season. Learn more about our eczema and allergy care.
Call us at (609) 808-3123 during office hours:
- Monday to Friday: 9:30 AM to 5:30 PM
- Saturday: 9:30 AM to 12:30 PM
Common Questions from Parents
How much Children's Zyrtec can I give my child?
Children's Zyrtec liquid is 5 mg per 5 mL. For ages 2 to 5, the label dose is 2.5 mL once a day, which can be increased to 5 mL once a day or 2.5 mL every 12 hours, with no more than 5 mL in 24 hours. For ages 6 and up it is 5 to 10 mL once a day, with no more than 10 mL in 24 hours.
How much Children's Claritin can I give my child?
Children's Claritin liquid is 5 mg per 5 mL. Children 2 to 5 years take 5 mL once a day, and children 6 and older take 10 mL once a day. Do not give more than that in 24 hours.
Can babies or toddlers under 2 take Zyrtec or Claritin?
The labels say to ask a doctor for children under 2. Pediatricians do sometimes prescribe a weight-appropriate dose of cetirizine for younger children with allergies or hives, so call us rather than estimating a dose yourself.
Is Zyrtec or Claritin better for kids?
Both work well for seasonal allergies and hives. Cetirizine (Zyrtec) tends to start working a little faster and is sometimes a bit stronger, but it causes mild drowsiness in more children. Loratadine (Claritin) is the least likely to cause drowsiness. If one does not help after a week or two, the other is worth trying.
Can my child take Zyrtec or Claritin every day?
Yes. For children with ongoing seasonal or year-round allergies, taking the medicine every day during allergy season usually controls symptoms better than taking it only on bad days. If your child needs it most of the year, let us know so we can look at triggers and other options such as a nasal steroid spray.
Sources
- DailyMed: Children's Zyrtec Allergy (cetirizine) syrup Drug Facts label (accessed October 26, 2026)
- DailyMed: Children's Claritin Allergy (loratadine) oral solution Drug Facts label (accessed October 26, 2026)
- HealthyChildren.org (AAP): Allergy Medicine for Children