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Cetirizine: uses and side effects

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 19.10.2023 | 3 minutes read

Cetirizine is a non-drowsy antihistamine available from any pharmacy. Adults and children can relieve symptoms from a range of allergies, including pollen (hay fever), dust, animal dander, or in response to insect bites. It can also calm contact dermatitis and atopic eczema.

Cetirizine relieves itching, sneezing, a runny nose, skin rash, and eye symptoms such as red, itchy, or watery. It is available in tablet, liquid gels, dissolvable tablets, and oral liquid forms. The branded version of cetirizine is Zyrtec.

Even though cetirizine is classed as a non-drowsy antihistamine, it can still cause drowsiness in some people. If you do experience drowsiness, it is advised that you avoid driving or drinking alcohol.

Doctor’s advice

How much should I take?

For adults and children over 12 years, cetirizine should be taken as a 10 mg once-daily dose unless directed differently by your doctor. Children aged 6 - 12 years can take 5-10 mg every 24 hours, and children aged 2 - 6 years can take 2.5 mg every 12 hours or 2.5-5 mg every 24 hours.

How does it work?

During an allergic reaction, your immune system releases a chemical called histamine, which is responsible for the symptoms of an allergy. Antihistamines work by opposing the actions of histamine by stopping histamine from binding to its target sites in the body.

The chemical structure of non-drowsy antihistamines makes them less likely to enter the brain through what is known as the blood-brain barrier. This makes them less likely to cause drowsiness compared to other antihistamines.

Who should avoid cetirizine?

Do not take cetirizine if you have previously had an allergic reaction to cetirizine or another ingredient listed in the medication or have reacted to an antihistamine in the past. Children under 2 years old should not take cetirizine unless prescribed by a doctor, and age restrictions can vary between different cetirizine products.

Speak with your doctor or pharmacist before taking cetirizine if you are pregnant or breastfeeding or have any of the following conditions: liver or kidney problems, epilepsy or seizures, or difficulty passing urine. You should avoid it if you are due for an allergy skin test.

Cetirizine can interact with other medicines, such as certain antidepressants and opioids. If you take any prescription, over-the-counter or herbal medicines, ask your doctor or pharmacist to check if they are safe to take alongside cetirizine.

Are there any side effects?

While it is generally well-tolerated, like any medication, cetirizine may cause side effects in some individuals. It's important to note that not everyone will experience these side effects, and they are typically mild. If you have concerns or experience any unusual symptoms, it's advisable to contact a healthcare professional. Common side effects of cetirizine may include:

  • Drowsiness: Although cetirizine is considered a non-sedating antihistamine, some people may still experience mild drowsiness. It is recommended to avoid activities that require alertness, such as driving or operating machinery, until you know how the medication affects you.

  • Dry mouth: Cetirizine can sometimes cause a sensation of dryness in the mouth.

  • Fatigue: Some individuals may experience fatigue or a feeling of tiredness while taking cetirizine.

  • Headache: Headaches are a possible side effect, although they are generally mild.

  • Sore throat: In some cases, cetirizine may lead to a sore throat.

  • Abdominal pain: Some individuals may experience mild abdominal discomfort.

  • Nausea: Nausea is a less common side effect but can occur in some cases.

It's important to seek medical attention if you experience severe or persistent side effects. Additionally, if you have a known allergy to cetirizine or any of its components, you should not take the medication.

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This article has been written by UK-based doctors and pharmacists, so some advice may not apply to US users and some suggested treatments may not be available. For more information, please see our T&Cs.
Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 19.10.2023
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