What is cetirizine 1mg mL syrup used for?

Cetirizine 1mg/mL syrup is an antihistamine medication used to relieve symptoms associated with allergies such as seasonal allergies, pet allergies, dust mite allergies, and skin allergies. It is sold under brand names like Zyrtec, Reactine, and Benadryl Allergy. Cetirizine works by blocking the effects of histamine, a chemical released by the body during an allergic reaction. This helps reduce inflammation, itching, sneezing, watery eyes and other bothersome symptoms. Cetirizine syrup can provide relief for both adults and children ages 2 years and older.

What conditions is cetirizine syrup used for?

Cetirizine syrup is primarily used to treat:

  • Seasonal allergic rhinitis (hay fever) – caused by tree, grass and weed pollen
  • Perennial allergic rhinitis – caused by year-round allergens like dust mites, pet dander or molds
  • Chronic idiopathic urticaria (CIU) – chronic hives of unknown cause
  • Allergic skin reactions – caused by allergens like poison ivy, bug bites, foods, medications

It provides relief from bothersome allergy symptoms like:

  • Sneezing
  • Itchy, watery eyes
  • Runny nose and nasal congestion
  • Itchy nose, throat or skin
  • Hives and skin rashes

Cetirizine is an effective treatment for common indoor and outdoor allergies. Both seasonal and year-round allergens can trigger an allergic reaction and associated uncomfortable symptoms that cetirizine helps relieve.

How does cetirizine syrup work?

Cetirizine belongs to a class of medications called second-generation antihistamines. It works by blocking the effects of histamine, a chemical released by the body during an allergic reaction.

When an allergen, like pollen or pet dander is inhaled or comes in contact with the skin, the immune system identifies it as a foreign invader and releases antibodies called immunoglobulin E (IgE). These antibodies then trigger mast cells to release histamine.

Histamine is responsible for typical allergy symptoms like:

  • Swelling and inflammation in nasal passages and skin
  • Itching of the nose, throat, eyes and skin
  • Excess mucus production resulting in runny nose and sneezing
  • Watery, itchy eyes

Cetirizine blocks histamine receptors and prevents it from binding to cells and triggering an allergic response and associated symptoms. This provides allergy relief.

What is the dosage of cetirizine syrup?

The recommended dosage of cetirizine syrup depends on the patient’s age:

  • Children 2-5 years: 2.5 mg (2.5 mL or 1⁄2 teaspoon) once daily
  • Children 6-11 years: 5 mg (5 mL or 1 teaspoon) once daily
  • Adults and children 12 years and older: 10 mg (10 mL or 2 teaspoons) once daily

Cetirizine syrup should be measured carefully using an oral syringe or measuring spoon. It can be taken with or without food. For best results, take at the same time each day.

When should cetirizine syrup be taken?

Cetirizine syrup can be taken at any time of day. However, taking it in the evening may be optimal for several reasons:

  • Helps improve sleep – Cetirizine is more sedating compared to other second-generation antihistamines. Taking it at night helps minimize daytime drowsiness.
  • Provides full 24 hour relief – A single evening dose provides coverage throughout the day when allergy symptoms tend to be worst.
  • Easier to remember – Taking it as part of a regular evening routine improves compliance.

The time of administration depends on the specific allergy symptoms being treated:

  • Seasonal allergies – best taken in the evening to cover symptoms that tend to be worst in the morning and during the day
  • Hives or itching – can be taken anytime symptoms occur for quick relief

Always follow the prescribing doctor’s instructions about when to take cetirizine syrup. Be consistent each day for best results.

What are the side effects of cetirizine syrup?

Cetirizine syrup is generally well tolerated. Most side effects are mild and may include:

  • Drowsiness
  • Fatigue
  • Dry mouth
  • Sore throat
  • Headache
  • Diarrhea or constipation

Children may experience agitation and excitability. Drowsiness is more common with cetirizine compared to other newer antihistamines. Taking the dose at bedtime and avoiding alcohol can help minimize daytime sleepiness.

Rarely, cetirizine may cause blurred vision, difficulty urinating, irregular heartbeat, tremors or muscle aches. Seek prompt medical attention if any severe side effects develop. Inform your doctor if side effects do not resolve on their own within a few days.

Who should not take cetirizine syrup?

Cetirizine syrup is contraindicated in patients:

  • With a known hypersensitivity to cetirizine or other ingredients in the formulation
  • With severe kidney disease or on dialysis
  • With a history of QT prolongation or related heart rhythm disorders

It should be used with caution in patients with any of the following:

  • Mild to moderate kidney disease
  • History of seizures
  • Difficulty urinating due to an enlarged prostate
  • Elderly patients at increased risk of side effects

Inform your doctor about any medical conditions before taking cetirizine. The medication is classified as pregnancy category B meaning it is likely safe but should be used cautiously during pregnancy. Tell your doctor if you are pregnant, may become pregnant or are breastfeeding.

Can cetirizine syrup be given to children?

Yes, cetirizine syrup can be given to children 2 years of age and older. The dosage is weight-based as follows:

  • Children 2-5 years: 2.5 mg (2.5 mL) once daily
  • Children 6-11 years: 5 mg (5 mL) once daily

The syrup form allows easy measurement and administration of weight-appropriate doses. Caregivers should use an oral syringe or medicine cup to measure each dose carefully before giving it.

Do not give cetirizine to a child younger than 2 years without medical advice. Use caution when giving cetirizine syrup to children with seizure disorders. Monitor children closely for increased sedation and behavior changes when starting treatment.

What precautions should be taken when using cetirizine syrup?

The following precautions should be taken when using cetirizine syrup:

  • Avoid driving or operating heavy machinery until you know how the medication affects you and your alertness.
  • Avoid drinking alcohol which can increase drowsiness.
  • Use caution when exercising or performing other tasks requiring mental alertness.
  • Rising slowly from a seated or lying position can help minimize dizziness.
  • Consult your doctor before taking any other prescription or OTC medications while using cetirizine.
  • Inform your doctor if you have any upcoming surgeries or dental procedures scheduled.
  • Call your doctor if allergy symptoms do not improve after taking cetirizine syrup regularly.

Monitor children closely for increased sedation when giving cetirizine syrup. Seek medical advice if unusual behavior changes develop. Counsel teenagers about the impacts on driving safety and school performance.

Can cetirizine syrup be taken long-term?

Yes, cetirizine syrup can generally be taken for extended or long-term use. In fact, continuing it daily throughout allergy season may be recommended for optimal relief.

Cetirizine is a second-generation antihistamine that demonstrates a lower risk of drowsiness and sedation compared to first-generation formulations like diphenhydramine. Studies show it retains effectiveness and safety even with prolonged use.

Some doctors recommend cetirizine as a daily preventative therapy for those with seasonal allergies. By maintaining stable blood levels, it can help prevent bothersome symptoms from developing in the first place. It may be used daily for several months at a time during peak pollen seasons.

For chronic hives or year-round allergies like dust mites, daily cetirizine may be recommended for extended periods as well. Just be sure to have regular checkups with your healthcare provider. Inform them about any new medications you start taking while using cetirizine long-term.

How long does it take for cetirizine syrup to work?

Cetirizine syrup typically starts working within 1 to 2 hours with maximum effects seen after 3 hours. Symptom relief lasts for a full 24 hours with a single dose.

Of course, the exact timeframe can vary based on the individual and type or severity of allergy symptoms being treated. For example:

  • Seasonal allergy relief may begin within 30 to 60 minutes with optimal relief in 2 to 3 hours.
  • Hives or itching may start improving more rapidly within 30 to 45 minutes.
  • Congestion and sneezing may take closer to 3 hours for more complete symptom control.

Cetirizine reaches peak concentrations in the bloodstream about 1 to 2 hours post-ingestion. It binds rapidly with histamine receptors and inhibits the allergic response and associated inflammation. Symptoms that develop suddenly like hives may respond more quickly than inflammation that takes time to build up like nasal congestion.

Be patient and take cetirizine syrup as directed. The first few days it may take time to control symptoms but relief should increase with continued daily use. Contact your doctor if allergy symptoms do not start improving within several days.

Can cetirizine syrup be taken with other medications?

Cetirizine has relatively few drug interactions, but there are some safety considerations:

  • Avoid taking with alcohol or sedating drugs – These increase drowsiness and sedation.
  • Use caution with ketoconazole, erythromycin – These can inhibit cetirizine metabolism.
  • Separate dosing from antacids – These can reduce absorption if taken together.
  • Monitor with CYP 3A4 inhibitors – These may inhibit cetirizine metabolism.

Inform your doctor about any prescription medications, over-the-counter drugs, vitamins and herbal supplements you are taking. Also disclose any pre-existing medical conditions.

Your doctor and pharmacist can provide guidance about using cetirizine safely with other medications based on your health history. Read packaging labels carefully and speak to a healthcare professional with any interaction concerns.

What are some alternatives to cetirizine syrup?

There are several alternatives to cetirizine syrup for treating allergies. These include both oral and nasal formulations:

  • Levocetirizine – Active enantiomer and metabolite of cetirizine, available as tablets and syrup.
  • Loratadine – Another second-generation antihistamine, available as tablets, syrup and melting tablets.
  • Fexofenadine – Related H1-antihistamine available as tablets or suspension.
  • Azelastine nasal spray – Antihistamine nasal spray for allergy symptoms.
  • Cromolyn sodium nasal spray – Mast cell stabilizer nasal spray.

Speak with your doctor or pharmacist about the best options for your specific symptoms and health history. While cetirizine is commonly recommended, there are several alternative medications that may also be effective allergy treatments.


Cetirizine 1mg/mL syrup is an effective second-generation antihistamine used to relieve symptoms of seasonal and year-round allergic rhinitis, chronic hives, and skin allergy reactions. It blocks histamine receptors and prevents the allergic response and associated inflammation characteristic of allergy symptoms. The syrup formulation allows convenient dosing for both adult and pediatric patients ages 2 years and older. When taken as directed, cetirizine syrup provides fast-acting, long-lasting relief of itching, sneezing, watery eyes, runny nose, hives, and other bothersome allergy symptoms. It has minimal drug interactions and side effects, especially when taken at night. Cetirizine syrup continues to be a commonly recommended first-line oral antihistamine therapy for people of all ages suffering from indoor and outdoor allergies.

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