Hydroxyzine (Vistaril)

Naomi Carr
Author: Naomi Carr Medical Reviewer: Dr. Jenni Jacobsen, PhD Last updated:

Hydroxyzine, also known as Vistaril, is an antihistamine, primarily used in the treatment of allergies and anxiety. Always take this medication exactly as prescribed and consult with your doctor before starting any other medication (prescribed or over the counter) while on hydroxyzine, as adverse effects can occur.

Hydroxyzine brand names

  • Vistaril

What is hydroxyzine prescribed for?

Hydroxyzine is approved by the US Food & Drug Administration for use in the treatment of anxiety, allergic reactions, and as a sedative before and after surgery [1]. It can also be prescribed off-label, for a use not approved by the FDA, as a treatment for insomnia, if it is deemed necessary by a medical professional [2].

The safety and effectiveness of the long-term use of hydroxyzine for anxiety has not been established, so it is typically prescribed for up to four months. However, if it is deemed necessary for treatment, a doctor can continue to prescribe hydroxyzine for long-term use [1].

How does hydroxyzine work?

Hydroxyzine works by limiting the effects of histamine, thereby reducing the prevalence of allergic reactions such as rash and itchiness [3].

It also acts as a sedative, by impacting activity in certain parts of the central nervous system, so it can be used as an effective treatment for anxiety and sleep disturbances [4][5].

How is hydroxyzine usually taken?

Hydroxyzine is available as a capsule, in 25mg, 50mg, and 100mg strengths, and as an oral suspension, with 25mg of hydroxyzine per 5ml.

Capsules should be swallowed whole without breaking or crushing. The oral suspension requires shaking prior to administration and directions from the prescribing physician should be followed carefully.

For the treatment of anxiety, you may be prescribed a dose of 50-100mg, to be taken up to four times per day.

For the treatment of allergic reactions, you will likely be prescribed 25mg, to be taken 3-4 times per day [1].

For the treatment of insomnia, you may be prescribed 25-100mg, to be taken in one dose prior to going to bed [2].

As a sedative before or after surgery, you may be given 50-100mg in one dose.

Hydroxyzine can be prescribed to children in lower doses, dependent on age and weight [1].

Hydroxyzine can also be prescribed as a PRN, to be taken as and when it is needed. Your doctor will inform you of the maximum amount you should take in a day [6].

Your doctor will likely monitor your physical and mental health throughout your treatment, and your response to the medication, adjusting your dosage if required.

This medication should be taken as prescribed, without missing a dose. If a dose is missed, take the medication as soon as possible, or if it is close to the next dosage time, skip the missed dose. Never take double your prescribed dose in one go, as this can have adverse effects and may increase the risk of side effects.

How long does hydroxyzine stay in your system?

After you begin taking hydroxyzine, you may begin to feel the effects within 30 minutes of your first dose [1].

When you stop taking hydroxyzine, the medication will entirely leave your system within 2 days [4].

Hydroxyzine side effects

When you begin taking a new medication, you may experience some common side effects. They will likely reduce within the first week or two, but if they continue or become problematic, consult with your doctor, as you may need a reduced dose or a change of medication.

Common side effects of hydroxyzine include [3][6]:

  • Dry mouth
  • Drowsiness
  • Dizziness
  • Headache
  • Confusion
  • Blurred vision

Serious side effects of hydroxyzine are less common but may still occur. Contact your doctor immediately if you experience any of the following:

  • Tremors or shaking
  • Seizures
  • Rash or blisters
  • Swelling of the face or mouth
  • Fever
  • Increased or irregular heart rhythm
  • Hallucinations

This is not a complete list of possible side effects of hydroxyzine. Always seek medical attention if you experience any side effects that you think may be due to your use of this medication.

Hydroxyzine precautions

Never take hydroxyzine without proper medical advice. It is important that your doctor is aware of any past or present mental health conditions you have experienced, to enable safe monitoring of your condition while on this medication, or to decide if it is safe for you.

Discuss with your doctor all your past and present physical health conditions, as they may impact your ability to take this medication safely.

Ensure you tell your doctor if you have had a serious heart condition as this medication may not be safe for you to take, or you may require a reduced dose and more frequent monitoring of your physical health [3].

Discuss with your doctor if you are pregnant or planning to become pregnant, as there is research to suggest that it may cause fetal abnormalities if taken in the first trimester, although it may be safe in the second and third trimester [6][7]. Your doctor will inform you of the risks so that you can make an informed decision about your treatment.

Inform your doctor if you are breastfeeding. Currently, research is not clear about how much hydroxyzine is excreted in breast milk, so it is recommended not to take this medication as it may cause harm to your baby [1].

This medication can cause drowsiness and sedation, so it is important to avoid driving until you are aware of how hydroxyzine affects you and it is safe to do so.

Tell your doctor about all medications you are currently taking, or plan to take (including vitamins and dietary supplements), as they may cause adverse reactions.

Hydroxyzine interactions

Due to its sedating effects, it is recommended to avoid or limit the dosage of any medications or substances that affect the central nervous system, such as other sedatives, opiates, barbiturates, and alcohol. Combining hydroxyzine with any of these substances can increase the risk of serious side effects and oversedation [1].

Other medications may interact with hydroxyzine, potentially increasing the risk of side effects or decreasing the effectiveness of your medication, such as other antihistamines, certain heart disease medications, some antibiotics, anticonvulsants, and mental health medications including some antidepressants, antipsychotics, and anti-anxiety medications [3].

Always discuss your medications with your doctor before starting a new treatment.

Hydroxyzine storage

Always keep all medications out of reach of children.

Store duloxetine in its original packaging, in airtight containers, and at room temperature (68°F to 77°F).

If you need to dispose of medication that is out of date or no longer needed, contact a health care professional to ensure it is disposed of appropriately. Never flush medications down the toilet or throw them in the trash, as this can create unnecessary risks.

What to do if you overdose on hydroxyzine

If you overdose on hydroxyzine, call a medical professional, or Poison Control at 1-800-222-1222, or in case of an emergency, call 911. Symptoms of a hydroxyzine overdose include oversedation, nausea or vomiting, dizziness, and seizure.

Frequently asked questions about hydroxyzine

If I’m no longer taking hydroxyzine, can I drink alcohol?

Alcohol should be avoided while taking hydroxyzine, as it can increase the sedating effects of the medication and increase the risk of side effects [1]. If hydroxyzine treatment is discontinued, it is safe to recommence drinking alcohol once the medication has fully left your system, and in safe amounts.

Consult with your doctor about drinking alcohol following hydroxyzine treatment, as they may make recommendations depending on your condition or other medications that you are taking.

Does hydroxyzine affect sleep?

Hydroxyzine has a sedating effect and can be used off-label in the treatment of insomnia. Clinical studies have found that it can reduce sleep disturbances and improve quality of sleep [2][8].

If you are concerned about the sedating effects of this medication, you may wish to consult with your doctor about alternative therapy or medication for your condition.

  1. Pfizer Inc. (Revised 2014). Vistaril (Hydroxyzine Pamoate) Capsules and Oral Suspension. Access Data FDA. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/011459s048%2C011795s025lbl.pdf
  2. Smith, E., Narang, P., Enja, M., & Lippmann, S. (2016). Pharmacotherapy for Insomnia in Primary Care. The Primary Care Companion for CNS Disorders, 18(2), 10.4088/PCC.16br01930. Retrieved from https://doi.org/10.4088/PCC.16br01930
  3. American Society of Health-System Pharmacists, Inc. (Revised 2017). Hydroxyzine. MedlinePlus. Retrieved from https://medlineplus.gov/druginfo/meds/a682866.html
  4. National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 3658, Hydroxyzine. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Hydroxyzine
  5. Ferreri, M., Hantouche, E.G., & Billardon, M. (1994). Value of Hydroxyzine in Generalized Anxiety Disorder: Controlled Double-Blind Study Versus Placebo. L’Encephale, 20(6), 785–791. Retrieved from https://pubmed.ncbi.nlm.nih.gov/7875114/
  6. The American Association of Psychiatric Pharmacists (AAPP) and the National Alliance on Mental Illness (NAMI). (2023). Hydroxyzine (Vistaril). NAMI. Retrieved from https://www.nami.org/About-Mental-Illness/Treatments/Mental-Health-Medications/Types-of-Medication/Hydroxyzine-(Vistaril)
  7. Brzezińska-Wcisło, L., Zbiciak-Nylec, M., Wcisło-Dziadecka, D., & Salwowska, N. (2017). Pregnancy: A Therapeutic Dilemma. Postepy dermatologii i alergologii, 34(5), 433–438. Retrieved from https://doi.org/10.5114/ada.2017.71108
  8. Hassinger, A.B., Bletnisky, N., Dudekula, R., & El-Solh, A.A. (2020). Selecting a Pharmacotherapy Regimen for Patients with Chronic Insomnia. Expert Opinion on Pharmacotherapy, 21(9), 1035–1043. Retrieved from https://doi.org/10.1080/14656566.2020.1743265
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Naomi Carr
Author Naomi Carr Writer

Naomi Carr is a writer with a background in English Literature from Oxford Brookes University.

Published: Mar 29th 2023, Last edited: Sep 22nd 2023

Dr. Jenni Jacobsen, PhD
Medical Reviewer Dr. Jenni Jacobsen, PhD LSW, MSW

Dr. Jenni Jacobsen, PhD is a medical reviewer, licensed social worker, and behavioral health consultant, holding a PhD in clinical psychology.

Content reviewed by a medical professional. Last reviewed: Mar 29th 2023
Medical Reviewer Medical Reviewer:
Dr. Jenni Jacobsen, PhD
Last reviewed: Mar 29th 2023 Dr. Jenni Jacobsen, PhD