Cetirizine hydrochloride

Brand names: Zyrtec

Why is Cetirizine hydrochloride prescribed?

Zyrtec is an antihistamine. It is prescribed to treat the sneezing; itchy, runny nose; and itchy, red, watery eyes caused by seasonal allergies such as hay fever. Zyrtec also relieves the symptoms of year-round allergies due to dust, mold, and animal dander. This medication is also used in the treatment of chronic itchy skin and hives.

Most important fact about Cetirizine hydrochloride

Zyrtec may cause drowsiness. Be especially careful driving or operating dangerous machinery or participating in any hazardous activity that requires full mental alertness until you know how you react to Cetirizine hydrochloride.

How should you take Cetirizine hydrochloride?

Take Zyrtec once a day, exactly as prescribed. This medication can be taken with or without food.

Zyrtec may make your mouth dry. Sucking hard candy, chewing a stick of gum, or melting bits of ice in your mouth can provide relief.

  • If you miss a dose...If you are taking Cetirizine hydrochloride on a regular schedule, take the forgotten dose as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take 2 doses at once.
  • Storage instructions...Store the tablets and syrup at room temperature. The syrup may be refrigerated.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Zyrtec.

  • Side effects in adults may include:Drowsiness, dry mouth, fatigue
  • Side effects in children aged 6 to 11 may include:Abdominal pain, coughing, diarrhea, headache, nosebleed, sleepiness, sore throat, wheezing

Why should Cetirizine hydrochloride not be prescribed?

Avoid Zyrtec if it causes a reaction, or if you have ever had a reaction to similar drugs.

Special warnings about Cetirizine hydrochloride

If you have kidney or liver disease, be sure to tell your doctor. Your dose of Cetirizine hydrochloride may have to be reduced.

Possible food and drug interactions when taking Cetirizine hydrochloride

You should avoid drinking alcohol or taking sedatives, tranquilizers, sleeping pills, or muscle relaxants while using Zyrtec. They can lead to increased drowsiness and reduced mental alertness. Among the products to avoid are the following:

AntidepressantsMuscle relaxantsPain-relieving narcoticsSedatives such as phenobarbitalSleeping pillsHigh doses of theophylline

Special information if you are pregnant or breastfeeding

The effects of Zyrtec during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, tell your doctor immediately. Zyrtec appears in breast milk and should not be used if you are breastfeeding.

Recommended dosage for Cetirizine hydrochloride


The usual starting dose is 5 or 10 milligrams once a day, depending on the severity of your symptoms. If you have a kidney or liver condition, the doctor will probably prescribe 5 milligrams daily.


The usual starting dose is 5 or 10 milligrams (1 or 2 teaspoonfuls of syrup) once a day. If your child has a kidney or liver condition, the doctor will probably prescribe the lower dose.


The usual starting dose is 2.5 milligrams (one-half teaspoonful) once a day. Dosage may be increased to a maximum of 5 milligrams (1 teaspoonful) once daily or 2.5 milligrams (one-half teaspoonful) every 12 hours. If the child has a kidney or liver condition, Zyrtec should not be given.


The usual starting dose is 2.5 milligrams (one-half teaspoonful) once a day. In children 12 to 23 months old, the dose can be increased to a maximum of 5 milligrams a day, given as 2.5 milligrams (one-half teaspoonful) every 12 hours. Zyrtec should not be used if your child has kidney or liver problems.


Any medication taken in excess can have serious consequences. In adults, the primary symptom of a Zyrtec overdose is extreme sleepiness. In children, restlessness and irritability may precede drowsiness. If you suspect an overdose, seek medical treatment immediately.

  • Cetirizine Prescribing Information (FDA)
  • Cetirizine Professional Patient Advice (Wolters Kluwer)
  • Cetirizine MedFacts Consumer Leaflet (Wolters Kluwer)
  • Zyrtec Prescribing Information (FDA)
  • Zyrtec Consumer Overview