Cetirizinum Uses, Dosage, Side Effects, Food Interaction and all others data.

Cetirizinum is a potent and highly selective antagonist of the peripheral histamine H1-receptor on effector cells in the GI tract, blood vessels and respiratory tract.

General effects and respiratory effects

Cetirizinum, the active metabolite of the piperazine H1-receptor antagonist hydroxyzine, minimizes or eliminates the symptoms of chronic idiopathic urticaria, perennial allergic rhinitis, seasonal allergic rhinitis, allergic asthma, physical urticaria, and atopic dermatitis.The clinical efficacy of cetirizine for allergic respiratory diseases has been well established in numerous trials .

Effects on urticaria/anti-inflammatory effects

Trade Name Cetirizinum
Availability Rx and/or OTC
Generic Cetirizine
Cetirizine Other Names Cetirizin, Cetirizina, Cetirizine, Cetirizinum
Related Drugs prednisone, loratadine, fluticasone nasal, montelukast, promethazine, diphenhydramine, Benadryl, Zyrtec, Xolair
Formula C21H25ClN2O3
Weight Average: 388.888
Monoisotopic: 388.155370383
Protein binding

The mean plasma protein binding of cetirizine is 93% .

Groups Approved
Therapeutic Class Sedating Anti-histamine
Available Country
Last Updated: September 19, 2023 at 7:00 am


Cetirizinum is used for the treatment of seasonal allergic rhinitis and conjunctivitis, perennial allergic rhinitis, pruritus and urticaria. It is also used in allergen induced asthma.

Cetirizinum is also used to associated treatment for these conditions: Chronic Idiopathic Urticaria, Flu caused by Influenza, Perennial Allergic Rhinitis (PAR), Pollen Allergy, Respiratory Allergy, Seasonal Allergic Rhinitis

How Cetirizinum works

Cetirizinum, a metabolite of hydroxyzine, is an antihistamine drug. Its main effects are achieved through selective inhibition of peripheral H1 receptors. The antihistamine activity of cetirizine has been shown in a variety of animal and human models. In vivo and ex vivo animal models have shown insignificant anticholinergic and antiserotonergic effects. In clinical studies, however, dry mouth was found to be more frequent with cetirizine than with a placebo. In vitro receptor binding studies have demonstrated no detectable affinity of cetirizine for histamine receptors other than the H1 receptors. Studies with radiolabeled cetirizine administration in the rat have demonstrated insignificant penetration into the brain. Ex vivo studies in the mouse have shown that systemically administered cetirizine does not occupy cerebral H1 receptors significantly .


Cetirizinum dosage


  • Adults and children over 6 years: 1 tablet (10 mg) once daily or ½ tablet twice daily.
  • Children 2-6 years: ½ tablet once daily.


  • Adults and children over 6 years: 2 teaspoonful (10 mg) once daily or 1 teaspoon (5 mg) twice daily.
  • Children 2-6 years: 1 teaspoonful once daily or ½ teaspoon twice daily.

Side Effects

Cetirizinum dihydrochloride is well tolerated. Lower incidence of sedation, headache, dry mouth, and gastrointestinal disturbances may occur. It does not produce anticholinergic effects.


Oral LD50 (rat): 365 mg/kg; Intraperitoneal LDLO (mouse): 138 mg/kg; Oral TDLO (rat): 50 mg/kg; Oral TDLO (mouse): 0.1 mg/kg .

Carcinogenesis and mutagenesis: In a 2-year carcinogenicity study in rats, cetirizine was not shown to be carcinogenic at dietary doses up to 20 mg/kg (approximately 15 times the maximum recommended daily oral dose in adults). In a 2-year carcinogenicity study in mice, cetirizine administration lead to an incidence of benign liver tumors in males at a dietary dose of 16 mg/kg (approximately 6 times the maximum recommended daily oral dose in adults). The clinical significance of these findings during long-term use of cetirizine is unknown at this time .

Cetirizinum was not mutagenic in the Ames test, and not clastogenic in the human lymphocyte assay, the mouse lymphoma assay, and in vivo micronucleus test in rats .

Impairment of fertility

In a fertility and reproduction study in mice, cetirizine did not negatively impact fertility at an oral dose of 64 mg/kg (approximately 25 times the maximum recommended daily oral dose in adults) .

Pregnancy Category B:

In mice, rats, and rabbits, cetirizine was not teratogenic at oral doses up to 96, 225, and 135 mg/kg, respectively (approximately 40, 180 and 220 times the maximum recommended daily oral dose in adults). There are no adequate and well-controlled studies in pregnant women. Because animal studies are not always predictive of human response, cetirizine should be used in pregnancy only if clearly needed .

Use in breastfeeding/nursing

Cetirizinum has been reported to be excreted in human breast milk. The use of cetirizine in nursing mothers is not recommended .


Caution should be exercised when driving a car or operating a heavy machinery. Concurrent use of cetirizine with alcohol or other CNS depressants should be avoided because additional reduction in alertness and CNS performance may occur.


No clinically significant drug interactions have been found with theophylline, azithromycin, pseudoephedrine, ketoconazole or erythromycin and with some other drugs.

Food Interaction

  • Avoid alcohol.
  • Take with or without food. The absorption is unaffected by food.

[Moderate] GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents.

Use in combination may result in additive central nervous system depression and
MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol.

Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

Cetirizinum Disease Interaction

Moderate: alcohol, renal/liver disease

Volume of Distribution

Apparent volume of distribution: 0.44 +/- 0.19 L/kg .

Elimination Route

Cetirizinum was rapidly absorbed with a time to maximum concentration (Tmax) of about 1 hour after oral administration of tablets or syrup formulation in adult volunteers . Bioavailability was found to be similar between the tablet and syrup dosage forms. When healthy study volunteers were given several doses of cetirizine (10 mg tablets once daily for 10 days), a mean peak plasma concentration (Cmax) of 311 ng/mL was measured .

Effect of food on absorption

Food had no effect on cetirizine exposure (AUC), however, Tmax was delayed by 1.7 hours and Cmax was decreased by 23% in the fed state .

Half Life

Plasma elimination half-life is 8.3 hours .


Apparent total body clearance: approximately 53 mL/min .

Cetirizinum is mainly eliminated by the kidneys , . Dose adjustment is required for patients with moderate to severe renal impairment and in patients on hemodialysis .

Elimination Route

Mainly eliminated in the urine , .

Between 70 – 85% of an orally administered dose can be found in the urine and 10 – 13% in the feces .

Pregnancy & Breastfeeding use

Pregnancy category B. There are no adequate and well controlled studies in pregnant women. Cetirizinum should be used during pregnancy only if clearly needed. Cetirizinum has been reported to be excreted in human breast milk. As large amount of drugs are excreted in human milk, use of Cetirizinum in nursing mother is not recommended.


Cetirizinum Dihydrochloride is contraindicated in those patients with a known hypersensitivity to it or any of its ingredients or hydroxyzine.

Acute Overdose

Symptoms: Confusion, dizziness, fatigue, headache, malaise, restlessness, sedation, somnolence, diarrhoea, mydriasis, pruritus, stupor, tachycardia, tremor, and urinary retention.

Management: Symptomatic and supportive treatment. Gastric lavage may be done shortly following ingestion.

Storage Condition

Store between 20-25°C. Syrup: Store between 2-8°C.

Innovators Monograph

You find simplified version here Cetirizinum

Cetirizinum contains Cetirizine see full prescribing information from innovator Cetirizinum Monograph, Cetirizinum MSDS, Cetirizinum FDA label


What is Cetirizinum used for?

Cetirizinum is an antihistamine medicine that helps the symptoms of allergies. It's used to treat hay fever, conjunctivitis.

How safe is Cetirizinum?

Cetirizinum is generally very safe. Taking more than the usual dose is unlikely to harm you or your child. If you take an extra dose, you might get some of the common side effects.

How does Cetirizinum work?

Cetirizinum works by blocking the action of histamine, a substance in the body that causes allergic symptoms.

What are the common side effects of Cetirizinum?

Common side effects of Cetirizinum are headaches, dry mouth, feeling sick, dizziness and diarrhoea.

Is Cetirizinum safe during pregnancy?

Many allergy drugs may be fine to keep taking during pregnancy, but have the discussion so you can have peace of mind.Cetirizinum should not be used during pregnancy unless the benefit outweighs the risk to the fetus.

Is Cetirizinum safe during breastfeeding?

Cetirizinum are the antihistamine tablets recommended if you're breastfeeding. They can have different Cetirizinum names, so speak to your pharmacist for advice.

Can I drink alcohol with Cetirizinum?

You should avoid or limit the use of alcohol while being treated with Cetirizinum.

Can I drive after taking Cetirizinum?

Do not drive a car, ride a bike, use tools or machinery until you do not feel tired anymore.

When is the best time to take Cetirizinum?

Cetirizinum can be taken at any time of the day. In most people it is non-sedating, so they take it in the morning. However, a percentage of people do find it to be sedating so if it does make you drowsy it is best to take it in the evening.

How long does it take for Cetirizinum to start working?

You should start to feel better within an hour. 

How long should I take Cetirizinum for?

Cetirizinum depends on why you're taking.You may only need to take it for a short time or as a one-off dose.

How long does it take for a Cetirizinum to kick in?

Usually, Cetirizinum start to work within 30 minutes after being taken and tend to be most effective within 1-2 hours after being taken.

Does Cetirizinum help with itching?

Cetirizinum is also used to treat itching and redness caused by hives.

Can I take Cetirizinum for a long time?

Cetirizinum is unlikely to do you any harm if you take it for a long time. However it's best to take Cetirizinum only for as long as you need to.

How long does Cetirizinum stay in my system?

The elimination half-life of Cetirizinum ranges from 6.5 to 10 hours in healthy adults, with a mean across studies of approximately 8.3 hours. Its duration of action is at least 24 hours.

Who should not take Cetirizinum?

Tell your doctor if you have or have ever had kidney or liver disease. tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking Cetirizinum, call your doctor. You should know that Cetirizinum may make you drowsy.

Can Cetirizinum be stopped suddenly?

Stopping Cetirizinum suddenly can result in unbearable itching.

Is it bad to take Cetirizinum everyday?

It is best to take Cetirizinum only for as long as you need to. If you take it regularly over a long period there's a very small chance of severe itching if you stop treatment suddenly. If you've been taking Cetirizinum every day for a long time, talk to your doctor before stopping it.

Is Cetirizinum bad for my liver?

Cetirizinum use are not generally associated with liver enzyme elevations, but have been linked to rare instances of clinically apparent liver injury.

Can Cetirizinum cause kidney damage?

Cetirizinum is eliminated primarily by the kidney but also undergoes metabolism in the liver to some extent.

Is Cetirizinum hard on kidneys?

In general, anti-histamines do not cause kidney problem.

Can I take Cetirizinum after meal?

Cetirizinum can be taken with or without food.

What happens if I miss a dose of?

Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine or add extra doses to make up the missed dose.

What happens if I overdose of Cetirizinum?

Seek emergency medical attention if you think you have used too much of this medicine.Overdose symptoms may include feeling restless or nervous, and then feeling drowsy.

*** Taking medicines without doctor's advice can cause long-term problems.