What Is Hydroxyzine and How Does It Work?

Hydroxyzine is used for the short-term treatment of nervousness and tension that may occur with certain mental/mood disorders (e.g., anxiety, dementia). It is also used to help manage withdrawal symptoms (e.g., anxiety, agitation) in alcoholics.

Other uses include helping to decrease anxiety and nausea before/after surgery or during childbirth or helping certain narcotic pain relievers (e.g., meperidine) work better.

  • Hydroxyzine belongs to a class of medications called antihistamines. It is thought to work by affecting certain natural substances (acetylcholine, serotonin) in your body or by acting directly on certain parts of the brain.
  • Hydroxyzine also blocks a natural substance that your body makes during an allergic reaction (histamine).
  • Hydroxyzine is available under the following different brand names: Vistaril.

What Are the Dosages of Hydroxyzine?

Dosages of Hydroxyzine:

Adult Dosage Forms and Strengths


  • 5 mg
  • 25 mg
  • 50 mg


  • 25 mg
  • 50 mg
  • 100 mg

Syrup/oral suspension

  • 10 mg/5mL

Injectable solution

  • 25 mg/5mL
  • 50 mg/5mL

Dosage Considerations – Should be Given as Follows:


  • Symptomatic relief of anxiety associated with psychoneurosis and as an adjunct in organic disease states
  • 50-100 mg orally divided every 6 hours or 50-100 mg intramuscularly (IM) divided every 4-6 hours
  • Younger than 6 years old: 50 mg/day orally divided every 6 hours
  • Children 6 years of age and older: 50-100 mg/day orally divided every 6 hours
  • Geriatric: 50-100 mg orally divided every 6 hours or 50-100 mg IM divided every 4-6 hours
  • Dosing considerations
    • Continuation of therapy for more than 4 months has not been studied; reassess the need for therapy periodically

Pruritus (Itching)

  • Management of pruritus due to chronic hives (urticaria), contact dermatoses, and histamine-mediated pruritus
  • 25 mg oral/intramuscular (IM) divided every 6-8 hours
  • Younger than 6 years old: 50 mg/day orally divided every 6 hours
  • Children 6 years of age and older: 50-100 mg/day orally divided every 6 hours
  • Geriatric: 25 mg oral/IM every 6-8 hours; increased to 25 mg every 6-8 hours

Preoperative Sedation

  • Adult: 50-100 mg orally or 25-100 mg intramuscularly (IM)
  • Pediatric: 0.6 mg/kg orally, or 0.5-1.1 mg/kg IM
  • Dosing considerations
    • If treatment is initiated IM, subsequent doses may be administered orally

Dose Modification

Renal Impairment

  • Greater than 50 mL/min: Dose adjustment not necessary
  • 50 mL/min or more: Administer 50% normal dose

Hepatic Impairment


  • Advanced age associated with reduced drug clearance and with greater risk of confusion, dry mouth, constipation, and other anticholinergic effects and toxicity; start at the low end of the dosage range, and observe closely

What Are Side Effects Associated with Using Hydroxyzine?

Side effects associated with use of Hydroxyzine, include the following:

  • Dry mouth
  • Drowsiness (usually transitory and may disappear in a few days of continued therapy or upon reduction of the dose)
  • Involuntary motor activity (tremor, convulsions) usually with doses considerably higher than those recommended
  • Clinically significant respiratory depression has not been reported at recommended doses

Postmarketing side effects of hydroxyzine reported include:

  • Allergic reactions
  • Headache
  • Hallucinations
  • Itching
  • Rash
  • Hives

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Hydroxyzine ?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Severe interactions of hydroxyzine include:

  • none

Serious interactions of hydroxyzine include:

Hydroxyzine has moderate interactions with at least 207 different drugs.

Mild Interactions of hydroxyzine include:

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.

What Are Warnings and Precautions for Hydroxyzine ?


  • This medication contains hydroxyzine
  • Do not take Vistaril if you are allergic to hydroxyzine or any ingredients contained in this drug.
  • Keep out of reach of children
  • In case of overdose, get medical help or contact a Poison Control Center immediately


  • Documented hypersensitivity or related product including cetirizine and levocetirizine and components of the formulation
  • Prolonged QT interval
  • SC, intra-arterial, or IV administration

Effects of Drug Abuse

  • No information provided

Short-Term Effects

  • See "What Are Side Effects Associated with Using Hydroxyzine ?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Hydroxyzine ?”


  • Nursing mothers
  • May cause CNS depression resulting in drowsiness; avoid driving or operating dangerous machinery
  • May cause over-sedation and confusion in elderly patients; start on lower doses and monitor closely; avoid use
  • Intramuscular (IM) only for parenteral use; switch to oral as soon as possible
  • Use caution in patients with narrow-angle glaucoma, prostatic hyperplasia, or respiratory disease (asthma or COPD)
  • Hydroxyzine may rarely cause acute generalized exanthematous pustulosis (AGEP), a serious skin reaction characterized by fever and numerous small, superficial, non-follicular, sterile pustules, arising within large areas of edematous erythema; if signs or symptoms suggest AGEP, do not resume use of hydroxyzine and consider alternative therapy; avoid cetirizine or levocetirizine in patients who have experienced AGEP or other hypersensitivity reactions with hydroxyzine, due to risk of cross-sensitivity
  • Drug interaction interview
  • Pregnancy and Lactation

    • Hydroxyzine is considered to be contraindicated in early (1st trimester) pregnancy until more human pregnancy data available; limited experience in human pregnancy, either for drug itself or drugs in same class or with similar mechanisms of action, including 1st trimester, current limited data suggests that the drug does not represent a significant risk of developmental toxicity including growth restriction, structural anomalies, functional/behavioral deficits, or death at any time in pregnancy
    • It is unknown if hydroxyzine is excreted in milk; use with caution while breastfeeding
Medscape. Hydroxyzine.

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