CETIRIZINE (Zyrtec): What is used for?

What is Cetirizine?

Cetirizine is a drug used to treat rhinitis and urticaria. The product ingredient is Cetirizine hydrochloride (hcl).

The brand names of Cetirizine in the United States are: Zyrtec, Aller-Tec, Equate Allergy Relief, All Day Allergy.

Mechanism of action (MOA)

Selective H1 antagonist. Inhibits the initial phase of the allergic reaction, and reduces the migration of inflammatory cells and the release of mediators associated with late response.

Therapeutic indications, uses and benefits of Cetirizine

Relieves nasal and ocular symptoms of seasonal and perennial allergic rhinitis and symptoms of idiopathic chronic urticaria in adults and children > 2 years.

Dosage of Cetirizine

Adults and adolescents > 12 years: 10 mg once/day. Children 6-12 years: 5 mg 2 times/day or 10 mg 1 time/day.

Children 2-6 years old or body weight < 30 kg: 2.5 mg 2 times/day or 5 mg once/day.

Renal insufficiency: Adults, moderate renal insufficiency (Clcr 30-49 ml/min): 5 mg once/day; severe renal insufficiency (Clcr < 30): 5 mg/48 h; children: individual adjustment according to Clcr, age and weight.

Method of administration 

Oral drops in solution: can be taken as is or diluted in water. If diluted, they should be taken immediately.


Hypersensitivity, hydroxyzine or other piperazinic derivative. End-stage renal disease (Clcr < 10 ml/min).

Warnings and precautions with Cetirizine

  • Moderate and severe renal failure, adjust dose. Risk of seizure, epilepsy.
  • Concomitance with: alcohol, CNS depressants.
  • Not recommended in children < 2 years. Inhibits allergy skin test, space 3 days.
  • Patients with predisposing factors to urinary retention.

Renal insufficiency

Contraindicated with end-stage renal disease (Clcr < 10 ml/min). Caution with moderate and severe renal insufficiency, adjust dose.
Adults, Clcr 30-49 ml/min: 5 mg 1 time/day; Clcr < 30: 5 mg/48 h.
Children: individual adjustment according to Clcr, age and weight.


Animal studies do not indicate harm, in pregnancy very few clinical data: caution.


This active ingredient is excreted in breast milk at concentrations representing between 0.25 and 0.90 of the plasma measurements, depending on the time of sampling after administration.
Caution should therefore be exercised when cetirizine is prescribed to lactating women.

Effects on driving ability

Objective measures have not shown relevant clinical effects of cetirizine, at recommended doses of 10 mg, on driving ability, sleep latency, and motor response.
Therefore, patients who are going to drive, perform potentially hazardous activities, or use machinery should consider their response to the drug.
In these sensitive patients, the combined use of alcohol or any CNS depressant may cause further decreases in alertness and impaired performance.

Adverse reactions and side effects of Cetirizine

Drowsiness, fatigue. In addition, in adults: headache, dizziness, dry mouth, abdominal pain, pharyngitis, nausea and in children 6 months-12 years: diarrhea, rhinitis.


Source: The content of this active ingredient has been written taking into account the clinical and molecular information of all medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the Substance Registration System (SRS) of the Food and Drug Administration (FDA) and the United States Pharmacopeia (USP).

In order to know in detail the information authorized by the FDA for each drug, you should consult the corresponding medication guide authorized by the FDA.


UNII: YO7261ME24
PubChem CID: 2678
NCI Thesaurus: C1042

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