Zyrtec for Children's Allergies: Side Effects and Dosing

Zyrtec (cetirizine) is an over-the-counter (OTC) antihistamine commonly used to treat allergy symptoms, such as runny nose, sneezing, watery eyes, and itchy eyes or throat.

Often used by adults, it can also be given to children in various products and formulations. While generally safe, some side effects can occur. These may include drowsiness, stomach-related problems, or dry mouth. Dosing for children may be different, too, so it's important to read the label for dosage guidance.

As an antihistamine, Zyrtec works by blocking the action of histamine, a substance in the body that contributes to symptoms of allergies.

Side Effects

Zyrtec is considered to be safe and well-tolerated in children. Common side effects of Zyrtec include:

• Feeling drowsy or excessively tired, although drowsiness is shown to be better tolerated in children than adults
• Dry mouth
• Stomach problems, such as stomach pain, diarrhea, or vomiting

Parents may want to know if Zyrtec will cause anxiety or behavioral issues. Generally, these issues should not occur with the proper dosage. However, an overdose of Zyrtec may cause symptoms such as irritability, restlessness, and extreme drowsiness.

Experiencing an allergic reaction is a rare but serious potential side effect. If your child experiences hives, difficulty breathing, or swelling around the face, lips, tongue, or throat, get emergency medical help.

Can Children Overdose on Zyrtec?

It is important to follow the dosing instructions properly to ensure your child takes the correct dose of Zyrtec. If you use the liquid formulation, measure the dose with a medicine measuring device, such as the measuring cup enclosed with the liquid or given to you at the pharmacy. Using a household measuring device like a kitchen spoon can prove inaccurate and may result in incorrect dosing.

Symptoms of a Zyrtec overdose may include restlessness, irritability, and/or drowsiness.

Other Precautions

Some things to consider before your child takes Zyrtec are:

• Zyrtec should not be used if your child is allergic to cetirizine, Xyzal (levocetirizine), or hydroxyzine.
• Consult a healthcare provider if your child has any medical conditions, such as kidney or liver disease.
• Zyrtec may cause drowsiness. Check with a healthcare provider before using if your child takes other medicines that causes drowsiness.

Types of Zyrtec for Children

According to the manufacturer's website, four types of Zyrtec are specifically formulated for children, including:

• Oral liquid
• Chewable tablets
• Dissolvable tablets

Dosage

Dosage guidance for Children's Zyrtec 2.5 mg chewables is:

• Ages 2 to under 6 years: Chew and swallow one tablet once a day. If needed, the dose may be increased to a maximum of two tablets once a day or one tablet every 12 hours.
• Ages 6 and older: Chew and swallow two tablets 5 milligrams (mg) or four tablets (10 mg) once a day, depending on symptom severity.

Dosage guidance for Children's Zyrtec Allergy Relief syrup is:

• Ages 2 to under 6: Take 2.5 milliliters (mL) once a day. If needed, the dose can be increased to a maximum of 5 mL daily or 2.5 mL every 12 hours.
• Ages 6 and older: 5 mL or 10 mL once daily, depending on symptom severity.

Dosage guidance for Children's Zyrtec 10 mg chewables for ages 6 and older is to chew and swallow one tablet once a day. 

Dosage guidance for Children's Zyrtec Dissolve tabs for ages 6 and older is to let one tablet dissolve in the mouth once daily.

Additional tips for Zyrtec dosing are:

• Zyrtec can be taken at any time of the day, with or without food.
• If drowsiness occurs, you can try giving the dose at night.
• When a smaller dose is taken twice daily, you can space the doses about 12 hours apart, such as 8 a.m. and 8 p.m.

Will Any Drugs Interact With Zyrtec?

Before your child takes Zyrtec, check with a healthcare provider or pharmacist to ensure there are no possible drug interactions. Be sure to mention all prescription drugs, OTC medicines, vitamins, and supplements your child is taking. Let your healthcare provider or pharmacist know if your child takes any of the following:

• Some antidepressants, such as trazodone
• Certain anxiety medications, such as benzodiazepines
• Other medications used to treat mental health conditions, such as Abilify (aripiprazole)
• Certain seizure medications, such as Depakote (divalproex) and Neurontin (gabapentin)
• Cold and allergy medications, such as Claritin (loratadine)
• Opioids, such as Hysingla ER (hydrocodone)
• Sleep-promoting medications, such as sedatives
• An asthma bronchodilator medication, such as Uniphyl or Theochron (theophylline)

When to See a Healthcare Provider

Along with taking allergy medicine, additional measures can be taken to prevent and control allergies, such as avoiding triggers.

According to the American College of Allergy, Asthma, and Immunology, you or your child should see an allergist if:

• Allergies are causing sinus infections, stuffy nose, or breathing difficulty.
• Allergy symptoms occur for several months out of the year.
• OTC treatments do not control symptoms or cause bothersome side effects.
• Symptoms interfere with quality of life and daily activities.
• Serious symptoms occur, such as difficulty catching your breath, wheezing, asthma attacks, frequent shortness of breath, or chest tightness.

Summary

Zyrtec is a commonly used OTC antihistamine for managing allergy symptoms in adults and children. Several Zyrtec products, including chewable tablets, syrup, and Dissolve Tabs, are formulated for children.

Common side effects like drowsiness and dry mouth are generally mild, but an overdose can lead to more severe symptoms such as irritability, restlessness, and extreme drowsiness.

Follow proper dosing instructions and consult a healthcare provider about potential drug interactions and precautions, especially if the child has existing medical conditions. Additionally, seeing an allergist is recommended if allergy symptoms are severe or persistent despite medication.