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Zyrtec

Generic name: cetirizine hydrochloride
Dosage form: Children's Zyrtec Hives Relief Syrup, Children's Zyrtec Allergy Relief Syrup, Children's Zyrtec Dissolve Tabs, Children's Zyrtec Chewables Allergy Medicine for kids ages 6+, Children's Zyrtec Chewable Allergy Medicine for kids ages 2+, Zyrtec Hives Relief Medicine Tablets, Zyrtec Liquid Gels, Zyrtec 24 Hour Allergy Relief Dissolve Tablets, Zyrtec Dye-Free Chewable Allergy Medicine
Drug class: Antihistamines

Medically reviewed by Melisa Puckey, BPharm. Last updated on Aug 25, 2026.

What is Zyrtec?

Zyrtec (cetirizine) is an over-the-counter antihistamine used to relieve allergy symptoms, including sneezing, itching, watery eyes, and a runny nose, and also reduces hives (urticaria).

Zyrtec is usually taken once a day.

Zyrtec is available as tablets, capsules, chewable tablets, dissolving tablets and an oral syrup, in strengths of 2.5 mg, 5 mg and 10 mg. Which product is suitable depends on age.

Allergy symptoms are caused by your immune system releasing histamine when triggered by allergens, such as pollen, dust, or pet dander. Zyrtec works by blocking histamine H1 receptors, which prevents histamine from triggering allergy symptoms. Once Zyrtec blocks the H1 receptor, allergy symptoms improve.

How does Zyrtec work?

Zyrtec is a second-generation antihistamine that works by blocking H1 histamine receptors in your body (not your brain or spinal cord). This means this medicine is less likely to cause drowsiness compared with some older antihistamines. When your immune system releases histamine due to allergies, Zyrtec works by preventing histamine from attaching to the receptors and triggering allergy symptoms. By blocking histamine, Zyrtec reduces allergy symptoms.

Before taking this medicine

You should not use Zyrtec if you are allergic to cetirizine or similar medicines such as levocetirizine or hydroxyzine.

Do not use Zyrtec to prevent hives from any known cause, such as foods, insect stings, medicines, or latex or rubber gloves. This medicine will not prevent hives or an allergic skin reaction from occurring.

Ask a doctor or pharmacist before using Zyrtec if you have any health problems.

To make sure this medicine is safe for you, tell your doctor if you have ever had:

Tell your doctor if you are pregnant. You should not use Zyrtec if you are breastfeeding.

Zyrtec side effects

Get emergency medical help if you have signs of an allergic reaction to Zyrtec: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Common Zyrtec side effects may include:

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Warnings

These warnings are for every Zyrtec product containing cetirizine HCl. Zyrtec products for hives have additional warnings that are listed in that product's own section below.

Do not use if you have ever had an allergic reaction to this product or any of its ingredients, or to an antihistamine containing hydroxyzine.

Ask a doctor before use if you have liver or kidney disease. Your doctor should determine if you need a different dose.

Ask a doctor or pharmacist before use if you are taking tranquilizers or sedatives.

When using this product:

Stop use and ask a doctor if an allergic reaction to this product occurs. Seek medical help right away.

If pregnant or breast-feeding:

Zyrtec product summary table

All Zyrtec products in this range contain cetirizine HCl. Only two are suitable for children under 6 years. The dose for adults 65 years and over depends on the strength of the product rather than on which product family it belongs to. People with liver or kidney disease should ask a doctor before use. See specific product information for more detail.

Allergy relief products

Product Form and strength Who can use it Children 2 to under 6 years Adults under 65 years and children 6 years and over Adults 65 years and over
Children's Zyrtec Allergy Relief Syrup Oral solution, 5 mg per 5 mL Adults and children 2 years and over 2.5 mL once daily. If needed, dose can be increased to a maximum of 5 mL once daily or 2.5 mL every 12 hours. Do not give more than 5 mL in 24 hours. 5 mL or 10 mL once daily 5 mL once daily
Children's Zyrtec 2.5 mg Chewable Allergy Medicine for kids ages 2+ Chewable tablet, 2.5 mg Adults and children 2 years and over 1 tablet (2.5 mg) once daily. If needed, dose can be increased to a maximum of 2 tablets (5 mg) once daily or 1 tablet (2.5 mg) every 12 hours. Do not give more than 2 tablets (5 mg) in 24 hours. 2 tablets (5 mg) or 4 tablets (10 mg) once daily 2 tablets (5 mg) once daily
Children's Zyrtec Dissolve 10 mg Tabs Orally disintegrating tablet, 10 mg Adults and children 6 years and over Ask a doctor One tablet once daily Ask a doctor
Children's Zyrtec Chewables Allergy Medicine for kids ages 6+ Chewable tablet, 10 mg Adults and children 6 years and over Ask a doctor One tablet once daily Ask a doctor
Zyrtec Allergy Relief Medicine 5 mg Tablets Tablet, 5 mg Adults and children 6 years and over Ask a doctor 1 tablet (5 mg) or 2 tablets (10 mg) once daily 1 tablet (5 mg) once daily
Zyrtec Allergy Relief Medicine 10 mg Tablets Tablet, 10 mg Adults and children 6 years and over Ask a doctor One tablet once daily Ask a doctor
Zyrtec Liquid 10 mg Gels Capsule, 10 mg Adults and children 6 years and over Ask a doctor One capsule once daily Ask a doctor
Zyrtec 24 Hour Allergy Relief Dissolve 10 mg Tablets, Citrus Flavored Orally disintegrating tablet, 10 mg Adults and children 6 years and over Ask a doctor One tablet once daily Ask a doctor
Zyrtec Dye-Free 10 mg Chewable Allergy Medicine Chewable tablet, 10 mg Adults and children 6 years and over Ask a doctor One tablet once daily Ask a doctor

Children 2 to under 6 years can only use Children's Zyrtec Allergy Relief Syrup or Children's Zyrtec 2.5 mg Chewable Allergy Medicine. See those product sections for the dose. Children under 2 years should not be given any Zyrtec product without asking a doctor.

Hives relief products

Product Form and strength Who can use it Usual dose, 6 years and over Adults 65 years and over

Children's Zyrtec Hives Relief Syrup

Oral solution, 5 mg per 5 mL

Adults and children 6 years and over

5 mL or 10 mL once daily

5 mL once daily

Zyrtec Hives Relief Medicine 10 mg Tablets

Tablet, 10 mg

Adults and children 6 years and over

One tablet once daily

Ask a doctor

Both hives products carry additional warnings that do not apply to the allergy relief products, including a severe allergy warning about the signs of anaphylactic shock. Read the full warnings in each product section before use.

For all Zyrtec products, consumers with liver or kidney disease should ask a doctor before use.

Zyrtec dosing information and products

Children's Zyrtec Allergy Relief Syrup (5 mg per 5 mL)

Cetirizine HCl 5 mg per 5 mL (1 mg/mL) Oral solution. For adults and children 2 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Children's Zyrtec Allergy Relief Syrup (5 mg per 5 mL)

Adults under 65 years and children 6 years and over

5 mL or 10 mL once daily depending upon severity of symptoms; do not take more than 10 mL in 24 hours.

Adults 65 years and over

5 mL once daily; do not take more than 5 mL in 24 hours.

Children 2 to under 6 years of age

2.5 mL once daily. If needed, dose can be increased to a maximum of 5 mL once daily or 2.5 mL every 12 hours. Do not give more than 5 mL in 24 hours.

Children under 2 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Children's Zyrtec Dissolve 10 mg Tabs

Cetirizine HCl 10 mg per orally disintegrating tablet. For adults and children 6 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Children's Zyrtec Dissolve 10 mg Tabs

Adults under 65 years and children 6 years and over

One 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours. A 5 mg product may be appropriate for less severe symptoms.

Adults 65 years and over

Ask a doctor.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Children's Zyrtec Chewables Allergy Medicine for kids ages 6+

Cetirizine HCl 10 mg per chewable tablet. For adults and children 6 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Children's Zyrtec 10 mg Chewables Allergy Medicine for kids ages 6+

Adults under 65 years and children 6 years and over

Chew and swallow 1 tablet (10 mg) once daily; do not take more than 1 tablet (10 mg) in 24 hours. A 5 mg product may be appropriate for less severe symptoms.

Adults 65 years and over

Ask a doctor.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Children's Zyrtec 2.5 mg Chewable Allergy Medicine for kids ages 2+

Cetirizine HCl 2.5 mg per chewable tablet. For adults and children 2 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Children's Zyrtec 2.5 mg Chewable Allergy Medicine for kids ages 2+

Children 2 to under 6 years of age

Chew and swallow 1 tablet (2.5 mg) once daily. If needed, dose can be increased to a maximum of 2 tablets (5 mg) once daily or 1 tablet (2.5 mg) every 12 hours. Do not give more than 2 tablets (5 mg) in 24 hours.

Adults under 65 years and children 6 years and over

Chew and swallow 2 tablets (5 mg) or 4 tablets (10 mg) once daily depending upon severity of symptoms; do not take more than 4 tablets (10 mg) in 24 hours.

Adults 65 years and over

Chew and swallow 2 tablets (5 mg) once daily; do not take more than 2 tablets (5 mg) in 24 hours.

Children under 2 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Children's Zyrtec Hives Relief Syrup (5 mg per 5 mL)

Cetirizine HCl 5 mg per 5 mL (1 mg/mL). Oral solution. For adults and children 6 years and over.

Used for

Reduces hives and relieves itching due to hives (urticaria). This product will not prevent hives or an allergic skin reaction from occurring.

Directions

Age or condition Dosage Children's Zyrtec Hives Relief Syrup (5 mg per 5 mL)

Adults under 65 years and children 6 years and over

5 mL or 10 mL once daily depending upon severity of symptoms; do not take more than 10 mL in 24 hours.

Adults 65 years and over

5 mL once daily; do not take more than 5 mL in 24 hours.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. The following additional warnings are specific to Children's Zyrtec Hives Relief Syrup (5 mg per 5 mL).

Severe allergy warning. Get emergency help immediately if you have hives along with any of the following symptoms:

These symptoms may be signs of anaphylactic shock. This condition can be life-threatening if not treated by a health professional immediately. Symptoms of anaphylactic shock may occur when hives first appear or up to a few hours later.

Not a substitute for epinephrine. If your doctor has prescribed an epinephrine injector for anaphylaxis or severe allergy symptoms that could occur with hives, never use this product as a substitute for the epinephrine injector. If you have been prescribed an epinephrine injector, you should carry it with you at all times.

Do not use to prevent hives from any known cause such as:

because this product will not stop hives from occurring. Avoiding the cause of your hives is the only way to prevent them. Hives can sometimes be serious. If you do not know the cause of your hives, see your doctor for a medical exam. Your doctor may be able to help you find a cause.

Ask a doctor before use if you have:

Stop use and ask a doctor if:

Other information

Zyrtec Allergy Relief Medicine 10 mg Tablets

Cetirizine HCl 10 mg per tablet. For adults and children 6 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Zyrtec Allergy Relief Medicine 10 mg Tablets

Adults under 65 years and children 6 years and over

One 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours. A 5 mg product may be appropriate for less severe symptoms.

Adults 65 years and over

Ask a doctor.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Zyrtec Allergy Relief Medicine 5 mg Tablets

Cetirizine HCl 5 mg per tablet. For adults and children 6 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Zyrtec Allergy Relief Medicine 5 mg Tablets

Adults under 65 years and children 6 years and over

1 tablet (5 mg) or 2 tablets (10 mg) once daily depending upon severity of symptoms; do not take more than 2 tablets (10 mg) in 24 hours.

Adults 65 years and over

1 tablet (5 mg) once daily; do not take more than 1 tablet (5 mg) in 24 hours.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Zyrtec Liquid 10 mg Gels

Cetirizine HCl 10 mg per capsule. For adults and children 6 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Zyrtec Liquid 10 mg Gels

Adults under 65 years and children 6 years and over

One 10 mg capsule once daily; do not take more than one 10 mg capsule in 24 hours. A 5 mg product may be appropriate for less severe symptoms.

Adults 65 years and over

Ask a doctor.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Zyrtec 24 Hour Allergy Relief Dissolve 10 mg Tablets Citrus Flavored

Cetirizine HCl 10 mg per orally disintegrating tablet. For adults and children 6 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Zyrtec 24 Hour Allergy Relief Dissolve 10 mg Tablets

Adults under 65 years and children 6 years and over

One 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours. A 5 mg product may be appropriate for less severe symptoms.

Adults 65 years and over

Ask a doctor.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings.

Other information

Zyrtec Dye-Free 10 mg Chewable Allergy Medicine

Cetirizine HCl 10 mg per chewable tablet. For adults and children 6 years and over.

Used for

Temporarily relieves these symptoms due to hay fever or other upper respiratory allergies:

Directions

Age or condition Dosage Zyrtec Dye-Free 10 mg Chewable tablet

Adults under 65 years and children 6 years and over

Chew and swallow 1 tablet (10 mg) once daily; do not take more than 1 tablet (10 mg) in 24 hours. A 5 mg product may be appropriate for less severe symptoms.

Adults 65 years and over

Ask a doctor.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. There are no additional product-specific warnings."

Other information

Zyrtec Hives Relief Medicine 10 mg Tablets

Cetirizine HCl 10 mg per tablet. For adults and children 6 years and over.

Used for

Reduces hives and relieves itching due to hives (urticaria). This product will not prevent hives or an allergic skin reaction from occurring.

Directions

Age or condition Dosage Zyrtec Hives Relief Medicine 10 mg Tablets

Adults under 65 years and children 6 years and over

One 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours. A 5 mg product may be appropriate for less severe symptoms.

Adults 65 years and over

Ask a doctor.

Children under 6 years of age

Ask a doctor.

Consumers with liver or kidney disease

Ask a doctor.

Warnings

See the Warning section above for warnings that apply to all Zyrtec cetirizine products, including this product. The following additional warnings are specific to Zyrtec Hives Relief Medicine 10 mg Tablets.

Severe allergy warning. Get emergency help immediately if you have hives along with any of the following symptoms:

These symptoms may be signs of anaphylactic shock. This condition can be life-threatening if not treated by a health professional immediately. Symptoms of anaphylactic shock may occur when hives first appear or up to a few hours later.

Not a substitute for epinephrine. If your doctor has prescribed an epinephrine injector for anaphylaxis or severe allergy symptoms that could occur with hives, never use this product as a substitute for the epinephrine injector. If you have been prescribed an epinephrine injector, you should carry it with you at all times.

Do not use to prevent hives from any known cause such as:

because this product will not stop hives from occurring. Avoiding the cause of your hives is the only way to prevent them. Hives can sometimes be serious. If you do not know the cause of your hives, see your doctor for a medical exam. Your doctor may be able to help you find a cause.

Ask a doctor before use if you have:

Stop use and ask a doctor if:

Other information

Questions? Call 1-800-343-7805 (toll-free) or 215-273-8755 (collect).

What happens if I miss a dose?

Zyrtec is used when needed. If you are on a dosing schedule, skip any missed dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include severe drowsiness, vision problems, agitation, fast heartbeats, stomach pain, nausea, vomiting, trouble walking, trouble swallowing or speaking.

What should I avoid while using Zyrtec?

Avoid driving or hazardous activity until you know how this medicine will affect you. Dizziness or drowsiness can cause falls, accidents, or severe injuries.

Drinking alcohol with this medicine can cause side effects.

What other drugs will affect Zyrtec?

Using Zyrtec with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Other drugs may interact with cetirizine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Does Zyrtec interact with my other drugs?

Common questions about Zyrtec

Is it OK to take antihistamines every day?

Yes, most people can take antihistamines every day, if they have daily symptoms of their allergies. If you have chronic allergies with daily symptoms, you may take a daily antihistamine. Continue reading

What cold medicine can you take with diabetes?

If you have diabetes and you catch a cold or flu, there are over-the-counter (OTC) medicines that are safe for you to take to help alleviate your symptoms. Check out our suggestions for pain and fever relievers, cough and congestion medications and more.

Remember to look for cold and flu medicines that are less likely to affect your blood sugar (glucose) levels, including sugar-free and alcohol-free options, or worsen any diabetes complications you may have.

Continue reading
Allegra vs Zyrtec: What's the difference?

Allegra has the lowest risk of sedation out of all antihistamines so is preferred if an antihistamine is needed for people working in safety-critical jobs. Even though Zyrtec is 3.5 times more likely to cause sedation than Allegra, it is still much less sedating than some older antihistamines such as promethazine.

Continue reading
Can you take Benadryl and Zyrtec together? Why it's not advised?

You should not take Benadryl and Zyrtec together unless directed by your doctor. Both are antihistamines, and combining them can increase risks for drowsiness, confusion, and other side effects.

Continue reading
Which antihistamines make you drowsy?

First-generation antihistamines, like Benadryl (diphenhydramine) and Chlor-Trimeton (chlorpheniramine), often cause sedation. This can include drowsiness, fatigue, and reduced alertness or concentration. Continue reading

Does Zyrtec cause weight gain?
Weight gain is not listed as a common side effect on the Zyrtec product label, and many people take Zyrtec without any change in weight. However, several studies show that adults and children who use H1 antihistamines regularly (including Zyrtec and Allegra) tend to have higher body weight, body mass index (BMI), waist size, and insulin levels than similar people who do not use these medicines.
Continue reading
Can you take antihistamines when pregnant?

According to the American College of Obstetricians and Gynecologists (ACOG), several over-the-counter (OTC) antihistamines may be taken during pregnancy. Older, first-generation antihistamines can be taken, but they may cause drowsiness. Newer, second-generation antihistamines can also be taken and have less risk of drowsiness. Continue reading

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.