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Know the basics|Know the precautions & warnings|Know the side effects|Know the interactions|Understand the dosage

Know the basics

What is cetirizine used for?

Cetirizine is a type of drug known as an antihistamine. Cetirizine works by binding to histamine H1-receptors on various cells of the body especially in the central nervous system, lungs, and white blood cells. By blocking histamine, it prevents symptoms such as sneezing, itchiness, redness, inflammation, and runny nose.

It is a second-generation antihistamine which causes less drowsiness when taken as compared to first-generation antihistamines (e.g. diphenhydramine).

Cetirizine is used to treat the symptoms of following:

  • Seasonal allergic rhinitis
  • Hay fever
  • Vasomotor rhinitis
  • Allergic conjunctivitis
  • Relieve symptoms of allergic reaction

How should I take cetirizine?

If you are taking the over-the-counter product to self-treat, read all directions on the product package before taking this medication. If you have any questions, consult your pharmacist. If your doctor has prescribed this medication, take it as directed, usually once daily.

If you are using the chewable tablets, chew each tablet well and swallow. If you are using the rapidly-dissolving tablet, allow the tablet to dissolve on the tongue and then swallow, with or without water. If you are using the liquid form of this medication, measure the dose carefully using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.

The dosage is based on your age, medical condition, and response to treatment. Do not increase your dose or take this medication more often than directed.

Tell your doctor if your allergy symptoms do not improve, if your hives do not improve after 3 days of treatment, or if your hives last more than 6 weeks. Get medical help right away if your condition worsens or if you think you have a serious medical problem (such as a very serious allergic reaction/anaphylaxis).

How do I store cetirizine?

Cetirizine is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store cetirizine in the bathroom or the freezer. There may be different brands of cetirizine that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush cetirizine down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Know the precautions & warnings

What should I know before using cetirizine?

You should not use this medication if you are allergic to cetirizine.

Before taking cetirizine, tell your doctor about all of your medical conditions.

Older adults may need to take a lower than normal dose. Follow your doctor’s instructions

Tell your doctor if you regularly use other medicines that make you sleepy (such as other cold or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxant, and medicine for seizures, depression, or anxiety). They can add to sleepiness caused by cetirizine. Cetirizine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Avoid drinking alcohol. It can increase some of the side effects of cetirizine.

Is it safe to take cetirizine during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category B according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

There is no available data on the use of cetirizine while breastfeeding. Compared to other antihistamines, cetirizine is less likely to cause drowsiness, and is safe to use while breastfeeding.

Know the side effects

What are the side effects of cetirizine?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using cetirizine and call your doctor at once if you have any of these serious side effects:

  • fast, pounding, or uneven heartbeat;
  • weakness, tremors (uncontrolled shaking), or sleep problems (insomnia);
  • severe restless feeling, hyperactivity;
  • confusion;
  • problems with vision; or
  • urinating less than usual or not at all.

Less serious side effects may include:

  • dizziness, drowsiness;
  • tired feeling;
  • dry mouth;
  • sore throat, cough;
  • nausea, constipation;

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with cetirizine?

Cetirizine may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, non-prescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with cetirizine?

Cetirizine may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Do not take this medication or other antihistamines with alcohol as it may induce excessive drowsiness. Taking food with cetirizine may reduce its absorption and efficacy. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with cetirizine?

Cetirizine may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. Renal impairment or kidney disease may cause reduced clearance of the drug and lead to toxicity. Lab tests should be done to determine if you have reduced creatinine clearance which may warrant dose reduction or substitution. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Understand the dosage

The information provided is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist before using this medication.

What is the dose of Cetirizine for an adult?

Adults and Children 12 Years and Older: The recommended initial dose of ZYRTEC (cetirizine) is 5 mg or 10 mg per day in adults and children 12 years and older, depending on symptom severity. Most patients in clinical trials started at 10 mg. ZYRTEC (cetirizine) is given as a single daily dose. The time of administration may be varied to suit individual patient needs.

What is the dose of Cetirizine for a child?

Children 6 to 11 Years: The recommended initial dose of ZYRTEC (cetirizine) in children aged 6 to 11 years is 5 mg or 10 mg once daily depending on symptom severity. The time of administration may be varied to suit individual patient needs.

Children 2 to 5 Years: The recommended initial dose of ZYRTEC (cetirizine) in children aged 2 to 5 years is 2.5 mg (½ teaspoon) syrup once daily. The dosage in this age group can be increased to a maximum dose of 5 mg per day given as 1 teaspoon syrup once a day or one ½ teaspoon syrup given every 12 hours, or one 5 mg chewable tablet once a day.

Children 6 months to <2 years: The recommended dose of ZYRTEC (cetirizine) syrup in children 6 months to 23 months of age is 2.5 mg (½ teaspoon) once daily. The dose in children 12 to 23 months of age can be increased to a maximum dose of 5 mg per day, given as ½ teaspoon (2.5 mg) every 12 hours. Syrup is recommended for children under the age of 2 years

How is cetirizine available?

Cetirizine is available in the following dosage forms and strengths:

  • Tablet, oral: 10mg.
  • Chewable tablet, oral: 5 mg, 10 mg
  • Solution, oral: 1mg/ml.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of cetirizine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Cetirizine https://www.nlm.nih.gov/medlineplus/druginfo/meds/a698026.html. Accessed October 22, 2020.

Cetirizine https://www.mims.com/philippines/drug/info/cetirizine?mtype=generic. Accessed October 22, 2020.

H1-receptors https://www.jacionline.org/article/S0091-6749(03)01878-5/fulltext. Accessed October 22, 2020.

Pharmacology of Antihistamines https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3667286/. Accessed October 22, 2020.

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Written by Stephanie Nicole Nera, RPh, PharmD on May 02, 2020
Medically reviewed by Stephanie Nicole Nera, RPh, PharmD