You know the symptoms: runny nose, sneezing, itchy and watery eyes. When your child has an allergy, you want to find a medication that can safely relieve their discomfort. With this article, we’ll tell you about an allergy medication called Zyrtec. We’ll explain what it does, how it works, and how you can use it safely to help treat your child’s allergy symptoms.

Safe use of Zyrtec for kids

Zyrtec comes in two over-the-counter versions: Zyrtec and Zyrtec-D. Zyrtec comes in five forms, and Zyrtec-D comes in one form. All forms of Zyrtec and Zyrtec-D are safe for use in children of certain ages. However, two forms of Zyrtec are labeled just for children.

The chart below describes the safe age ranges for each over-the-counter form of Zyrtec and Zyrtec-D.

NameRoute and formStrength(s)Safe for ages*
Children’s Zyrtec Allergy: Syrup oral syrup5 mg/5 mL2 years and older
Children’s Zyrtec Allergy: Dissolve Tabsorally disintegrating tablet10 mg6 years and older
Zyrtec Allergy: Tabletsoral tablet10 mg6 years and older
Zyrtec Allergy: Dissolve Tabsorally disintegrating tablet10 mg6 years and older
Zyrtec Allergy: Liquid Gelsoral capsules10 mg6 years and older
Zyrtec-Dextended-release oral tablet5 mg, 120 mg12 years and older
* Note: If your child is younger than the age listed for a drug, ask your child’s doctor for guidance. They’ll explain if you can use the drug for your child’s allergies and how to use it.

Zyrtec is also available by prescription as an oral syrup. Your doctor can tell you more about the prescription version.

How Zyrtec and Zyrtec-D work to relieve allergy symptoms

Zyrtec contains an antihistamine called cetirizine. An antihistamine blocks a substance in the body called histamine. This substance can cause an allergic reaction when you’re exposed to allergens. By blocking histamine, Zyrtec works to relieve allergy symptoms such as:

  • runny nose
  • sneezing
  • itchy or watery eyes
  • itchy nose or throat

Zyrtec-D contains two drugs: cetirizine and a decongestant called pseudoephedrine. It relieves the same symptoms as Zyrtec, plus other symptoms. Because it contains a decongestant, Zyrtec-D also helps to:

  • reduce congestion and pressure in your child’s sinuses
  • increase drainage from your child’s sinuses

Zyrtec-D comes as an extended-release tablet that your child takes by mouth. The tablet releases the drug slowly into your child’s body over 12 hours. Your child should swallow the Zyrtec-D tablet whole. Do not allow them to break it or chew it.

Further reading: All about decongestants »

Dosage and length of use for Zyrtec and Zyrtec-D

Follow the dosage instructions on the package for both Zyrtec and Zyrtec-D. The dosage information is based on age. For Zyrtec, you should give your child one dose per day. For Zyrtec-D, you should give your child one dose every 12 hours. Be sure to avoid giving your child more than the maximum dosage listed on the package. To find out for how long your child can take these drugs safely, talk with your child’s doctor.

Learn more: Allergy causes, types, and treatments »

Side effects and warnings

Like most drugs, Zyrtec and Zyrtec-D have some side effects. They also have some warnings. If you have any questions about the effects of these drugs, ask your child’s doctor or your pharmacist.

Side effects of Zyrtec and Zyrtec-D

The more common side effects of Zyrtec and Zyrtec-D include:

  • drowsiness
  • dry mouth
  • pain in the abdomen
  • diarrhea
  • vomiting

Zyrtec-D can also cause these additional side effects:

  • increased heart rate
  • feeling jittery
  • not feeling tired at bedtime

Zyrtec can also cause serious side effects. Call your child’s doctor or 9-1-1 right away if your child has any serious side effects, which can include:

  • trouble breathing
  • trouble swallowing

Overdose warning

If your child takes too much Zyrtec or Zyrtec-D, it can cause very serious side effects. Symptoms of an overdose can include:

  • restlessness
  • irritability
  • extreme drowsiness

If you think your child has taken too much of either drug, call your child’s doctor or local poison control center. If your child’s symptoms are severe, call 9-1-1 or go to the nearest emergency room.

Drug interactions

Before your child starts taking Zyrtec or Zyrtec-D, talk to your child’s doctor or your pharmacist. Tell them about any medications, vitamins, or herbs your child is taking. This includes over-the-counter medications. Some of these substances may interact with Zyrtec or Zyrtec-D. An interaction is when a substance changes the way a drug works. Interactions can cause harmful effects or keep the drug from working well.

Talking to your child’s doctor or pharmacist is especially important if your child takes any drugs that have been shown to interact with Zyrtec or Zyrtec-D. Examples of these drugs include:

  • metoclopramide
  • opiates such as hydrocodone or oxycodone
  • other antihistamines such as dimenhydrinate, doxylamine, or loratadine
  • thiazide diuretics such as hydrochlorothiazide or chlorthalidone
  • sedatives such as zolpidem or temazepam

Conditions of concern

Zyrtec or Zyrtec-D may cause health problems when used in children with certain health conditions. Examples of conditions that may lead to problems with Zyrtec use include:

  • liver disease
  • kidney disease

Examples of conditions that may lead problems with Zyrtec-D use include:

  • diabetes
  • liver disease
  • kidney disease
  • heart problems
  • thyroid problems

If your child has any of these conditions, Zyrtec or Zyrtec-D may not be the best option to treat their allergies. Talk with your child’s doctor about the condition before giving your child Zyrtec or Zyrtec-D.

Talk with your doctor

Your child’s allergy can’t be cured, but treatments such as Zyrtec and Zyrtec-D may help relieve their symptoms. If you have questions about these drugs or other allergy medications, be sure to talk with your child’s doctor. They’ll work with you to find a treatment that will help relieve your child’s symptoms so your child can live more comfortably with their allergy.