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Hydroxyzine: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Aug 17, 2022.

1. How it works

  • Hydroxyzine may be used to relieve itch or as a premedication before surgery to relieve anxiety.
  • Experts are not sure exactly how hydroxyzine works in the brain but suggest it may suppress activity in certain key regions of the subcortical area of the central nervous system (which is the part of the brain located below the cerebral cortex).
  • Hydroxyzine has demonstrated bronchodilator activity (opening up of the airways); antihistaminic (relieves symptoms of allergy including itch), antiemetic (relieves nausea and vomiting), and analgesic (pain-relieving) effects; as well as skeletal muscle relaxation.
  • Hydroxyzine belongs to the class of drugs known as diphenylmethanes. It may also be called an antihistamine.

2. Upsides

  • Effective at relieving itching due to allergies or dermatitis (eczema).
  • Has a calming effect and can cause drowsiness which means it may be used as a premedication before surgery or given following surgery.
  • The calming effect of hydroxyzine may be useful for some people with anxiety who have not responded to other treatments, such as benzodiazepines. Has been used to allay anxiety before and after giving birth or to quickly calm down hysterical or acutely disturbed patients.
  • Has been used off-label for certain bladder disorders.
  • Has been used to control motion sickness or to relieve nausea or vomiting associated with various etiologies, such as surgery.
  • Available as an oral capsule, oral suspension, or an injectable product.
  • Generic hydroxyzine is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Drowsiness that may impair reaction skills, and affect a person's ability to drive or operate machinery. Alcohol should be avoided.
  • May cause a dry mouth, mild skin eruptions or a rash, headache, hallucinations. Side effects are generally mild and transient.
  • When used to manage itching or anxiety, hydroxyzine is usually taken four times a day.
  • Although it is sometimes used to manage itching, hydroxyzine may cause itching in some people. It may also cause a serious skin reaction called acute generalized exanthematous pustulosis (AGEP), characterized by fever and a severe rash.
  • Use of hydroxyzine as an antianxiety agent for more than four months has not been assessed in clinical studies.
  • Hydroxyzine is not suitable for some people including those who are allergic to cetirizine or levocetirizine, with a heart condition that causes a prolonged Q-T interval on ECG, or during early pregnancy.
  • It is not clear if elderly people are more sensitive to the effects of hydroxyzine. As a precaution, lower dosages should be used, at least on initiation.
  • May interact with some other medications such as barbiturates, meperidine, narcotics, and other central nervous system depressants, and cause excessive drowsiness. The dosage of these medications may need to be reduced.
  • Hydroxyzine is contraindicated during early pregnancy and there are reports that neonates exposed to hydroxyzine during late pregnancy or while being born have experienced central nervous system depression, clonic movements, extrapyramidal symptoms, low blood pressure, movement disorders, hypoxic conditions, or urinary retention. There are no controlled studies in humans and hydroxyzine should only be used during pregnancy if the benefits justify the risk. Use is not recommended during breastfeeding and the active metabolite of hydroxyzine, cetirizine, is excreted into breast milk. Serious side effects have been reported in breastfed newborns/infants. Some experts suggest using alternative antihistamines such as desloratadine, fexofenadine, or loratadine.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Hydroxyzine may be used to relieve anxiety or itching; however, it causes sedation so can affect a person's ability to drive or operate machinery. It should not be used during pregnancy or while breastfeeding unless the benefits outweigh the risks.

5. Tips

  • May be taken with or without food.
  • Avoid alcohol.
  • Do not drive, operate machinery, or perform tasks requiring alertness if this medicine makes you drowsy.
  • Hydroxyzine is available as capsules and an oral suspension. If using the oral suspension, shake it vigorously before use to ensure the proper resuspension of the active ingredient.
  • Seek urgent medical advice if you develop any signs of an allergic reaction (such as hives; difficult breathing; swelling of your face, lips, tongue, or throat); or a severe skin reaction; if your heart starts to beat fast or pounds; a headache accompanied by chest pain; severe dizziness; or seizures.
  • Tell your doctor if you are breastfeeding, pregnant, or intend to become pregnant before taking hydroxyzine because it may not be suitable for you.

6. Response and effectiveness

  • Hydroxyzine is rapidly absorbed from the gastrointestinal tract and its clinical effects are usually apparent within 15 to 30 minutes after oral administration.
  • The sedative effect of hydroxyzine usually takes 15 to 30 minutes to come on and persists for 4 to 6 hours following a single dose. Hydroxyzine can suppress the inflammatory response and itch associated with intradermal skin tests with allergens and histamine for up to 4 days.

7. Interactions

Medicines that interact with hydroxyzine may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with hydroxyzine. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with hydroxyzine include:

  • Alzheimer's disease medications, such as donepezil or galantamine
  • anticholinergics, such as benztropine or scopolamine
  • antipsychotics, such as chlorpromazine, clozapine, fluphenazine, thioridazine, risperidone, or trazodone
  • medications that can induce drowsiness, such as sleeping pills, first-generation antihistamines, muscle relaxants, most antidepressants, and anti-anxiety medications
  • nervous system depressants, such as barbiturates
  • pain relievers, such as acetaminophen, aspirin, ibuprofen, codeine, hydrocodone, or oxycodone.

Avoid drinking alcohol because it may increase the side effects of hydroxyzine.

Note that this list is not all-inclusive and includes only common medications that may interact with hydroxyzine. You should refer to the prescribing information for hydroxyzine for a complete list of interactions.


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use hydroxyzine only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2023 Revision date: August 16, 2022.