From the FDA Drug Label
Directions Adults and children 6years and overone 10 mg tablet once daily, do not take more than one 10 mg tablet in 24 hours. ... Children under 6 years of ageAsk a doctor The FDA drug label does not answer the question.
From the Research
Zyrtec (cetirizine) is not recommended for infants under 6 months of age, and for infants 6 months and older, the recommended dose is 2.5 mg (half of a 5 mg tablet or 2.5 ml of the children's liquid formulation) once daily, as supported by the study 1 that evaluated the safety of cetirizine in infants 6 to 11 months of age.
Important Considerations
- This medication should only be given to a 6-month-old under the direct supervision and prescription of a pediatrician, as antihistamines are not routinely recommended for young infants.
- If your 6-month-old is experiencing allergy symptoms, consult with your pediatrician before administering any medication.
- They may recommend starting with non-medication approaches first, such as avoiding allergens, using saline nasal sprays, or a cool-mist humidifier.
Mechanism of Action and Side Effects
- Cetirizine works by blocking histamine receptors, which helps reduce allergy symptoms like runny nose, sneezing, and itching.
- Young infants metabolize medications differently than older children and adults, making proper dosing crucial.
- Side effects may include drowsiness, dry mouth, or irritability, and any concerning reactions should prompt immediate medical attention, as noted in the study 2 that reported a case of insomnia in a 23-month-old male taking cetirizine.
Additional Guidance
- The study 1 found that cetirizine was well tolerated in infants 6 to 11 months of age, with no differences in all-cause or treatment-related adverse events compared to placebo.
- However, it is essential to prioritize caution and consult with a pediatrician before administering cetirizine to a 6-month-old infant, as the evidence is limited, and the potential risks and benefits must be carefully weighed, as discussed in the review 3 of cetirizine's use in allergic disorders.