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Drugs reference index «Hydroxyzine»



Pronunciation: (high-DROX-ih-zeen)Class: Antianxiety, Piperazine, nonselective

Trade Names:Hydroxyzine Hydrochloride- Tablets 10 mg- Tablets 25 mg- Tablets 50 mg- Tablets 100 mg- Syrup 10 mg per 5 mL- Injection 25 mg/mL

Trade Names:Vistaril- Capsules 25 mg (as pamoate)- Capsules 50 mg (as pamoate)- Capsules 100 mg (as pamoate)

Apo-Hydroxyzine (Canada)


May be caused by suppression of activity in subcortical areas of CNS.



Hydroxyzine is readily absorbed in the GI tract. T max is approximately 3 h and C max is 82 ng/mL.


Hydroxyzine is metabolized by the liver.


The mean t ½ is 3 h (reported to be up to 20 h; may be longer in elderly).


Onset is 15 to 30 min (oral).


Time to peak is 1 to 2 h.


Duration is 4 to 6 h.

Indications and Usage

Symptomatic relief of anxiety and tension associated with psychoneurosis; adjunct therapy in organic disease states with anxiety; management of pruritus caused by allergic conditions; sedative before and after general anesthesia (PO, IM).


Early pregnancy; hypersensitivity to hydroxyzine or cetirizine.

Dosage and Administration


PO / IM 50 to 100 mg 4 times daily.

Children older than 6 yr of age

PO 50 to 100 mg/day in divided doses.

Children younger than 6 yr of age

PO 50 mg/day in divided doses.


PO / IM 25 mg 3 or 4 times daily.

Children older than 6 yr of age

PO 50 to 100 mg/day in divided doses.

Children younger than 6 yr of age

PO 50 mg/day in divided doses.

Psychiatric and Emotional EmergenciesAdults

IM 50 to 100 mg stat and every 4 to 6 h as needed.


PO / IM 50 to 100 mg.


PO / IM 0.6 mg/kg.

General Advice

  • Administer without regard to meals. Administer with food if GI upset occurs.
  • Measure and administer prescribed dose of syrup using dosing cup, dosing spoon, or dosing syringe.
  • For IM administration only. Not for intradermal, subcutaneous, IV, or intra-arterial administration.
  • Do not administer if particulate matter, cloudiness, or discoloration noted.
  • Administer prescribed dose to adults by deep IM injection into the upper outer quadrant of the buttock or mid-lateral thigh.
  • Administer prescribed dose to children by deep IM injection into mid-lateral muscles of the thigh. Avoid upper outer quadrant of gluteal region unless absolutely necessary (eg, burn patient).


Store capsules, tablets, syrup, and injection at controlled room temperature (59° to 86°F). Protect syrup from freezing and light.

Drug Interactions

Alcohol and CNS depressants

CNS depressant effects may be increased.

Laboratory Test Interactions

None well documented.

Adverse Reactions


Chest tightness.


Transitory drowsiness; involuntary motor activity, including tremor and convulsions.


Dry mouth.


Hypersensitivity reactions (eg, wheezing, shortness of breath).



Category C .


Cetirizine, a metabolite of hydroxyzine, has been detected in breast milk. Therefore, hydroxyzine is not recommended.

ECG abnormalities

Particularly alterations in T-waves have been associated with anxiolytic doses.


Clinical exacerbations have occurred.




Patient Information

  • Advise patient that medication is usually started at a low dose and then gradually increased until max benefit is obtained.
  • Caution patient to take as prescribed and not to stop taking or change the dose unless advised by health care provider.
  • Advise patient to take as prescribed without regard to meals but to take with food if stomach upset occurs.
  • Advise patient or caregiver using syrup to measure and administer prescribed dose using dosing syringe, dosing spoon, or dosing cup.
  • Advise patient that if a dose is missed, to take it as soon as possible, unless it is nearing time for the next scheduled dose. Then, skip the missed dose and take the next dose at the regularly scheduled time. Caution patient not to double the dose to catch up.
  • Advise patient that if symptoms are not controlled, not to increase the dose of medication or frequency of use, but to inform health care provider. Caution patient that larger doses or more frequent dosing does not increase effectiveness and may cause excessive drowsiness or other adverse reactions.
  • Instruct patient to contact health care provider if symptoms do not appear to be getting better, are getting worse, or if bothersome adverse reactions (eg, drowsiness, dizziness) occur.
  • Caution patient not to take any OTC antihistamines while taking this medication unless advised by health care provider.
  • Caution patient that alcohol and other CNS depressants (eg, sedatives) will have additional sedative effects if taken with hydroxyzine.
  • Caution patient that drug may cause drowsiness and to use caution driving or performing other tasks requiring mental alertness until tolerance is determined.
  • Advise patient to take frequent sips of water, suck on ice chips or sugarless hard candy, or chew sugarless gum if dry mouth occurs.
  • If patient is to have allergy skin testing, advise patient not to take the medication for at least 4 days before skin testing.

Copyright © 2009 Wolters Kluwer Health.

  • Hydroxyzine Prescribing Information (FDA)
  • Hydroxyzine MedFacts Consumer Leaflet (Wolters Kluwer)
  • Atarax MedFacts Consumer Leaflet (Wolters Kluwer)
  • Atarax Detailed Consumer Information (PDR)
  • Atarax Consumer Overview
  • Atarax Prescribing Information (FDA)
  • Vistaril Prescribing Information (FDA)
  • Vistaril Consumer Overview

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