Hydroxyzine (Vistaril): dosage, uses, side effects

last updated: Jul 21, 2021

5 min read

When you think about antihistamines, you’re probably picturing itchy eyes, a runny nose, and lots of sneezes. But did you know that some antihistamines, like hydroxyzine, can treat anxiety symptoms too? 

If you’re looking to get better control over your anxiety, here’s what you should know about hydroxyzine and how it may be able to help you. 


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What is hydroxyzine?

Hydroxyzine (brand name Vistaril, Atarax) is an antihistamine used to treat anxiety and allergy symptoms (Pfizer, 2019). 

Histamine, a chemical in your body, has many functions, one of which includes helping your body produce an allergic response. Hydroxyzine blocks histamine and can help treat itching and hives (Patel, 2021). Hydroxyzine also affects other chemicals in your body, including serotonin in the brain. Researchers believe this may explain why it is also effective for treating anxiety symptoms (Abejuela, 2016). 

Hydroxyzine uses 

Hydroxyzine is a prescription drug approved by the U.S. Food and Drug Administration (FDA) for short-term treatment of anxiety and to treat itching (pruritus) and hives (urticaria) caused by certain skin conditions (Pfizer, 2019). 

The first-line treatment of anxiety often involves the use of SSRI antidepressants (like Paxil), SNRIs (like Effexor XR), or buspirone (brand name Buspar). But these medications take several weeks to become effective and can leave you struggling with your symptoms in the meantime. Healthcare providers may prescribe benzodiazepines (like Xanax or Klonopin) that you can use during this period. Still, these medications have the potential for dependence or abuse (Guaiana, 2010). 

Hydroxyzine, like benzodiazepines, works immediately while not being associated with the same risks.

Healthcare providers can prescribe hydroxyzine by itself or with other medications to treat anxiety. Its sedative effects make it a great option if your anxiety causes you to have difficulty sleeping as well (Abejuela, 2016). 

Hydroxyzine side effects 

Drowsiness is a common side effect of hydroxyzine. Most people start to feel less sleepy after a few days or after reducing their dose (Pfizer, 2019). Let your healthcare provider know if your hydroxyzine makes you feel too tired and interferes with your daily activities. 

Other common side effects of hydroxyzine include dry mouth, headache, and confusion (Pfizer, 2019). 

Rarely, hydroxyzine can cause a serious skin reaction called acute generalized exanthematous pustulosis (AGEP) (Pfizer, 2019). If it occurs, this condition typically develops within 1–2 days after starting the medication. Symptoms of AGEP include red, itchy, pus-filled bumps on the skin and a fever (Szatkowski, 2015). AGEP can cause serious complications, so seek medical advice right away if you develop a skin rash while taking hydroxyzine or if a skin rash you previously had becomes worse (Pfizer, 2019). 

Hydroxyzine dosage 

Hydroxyzine is available in 10 mg, 25 mg, 50 mg, and 100 mg tablets and capsules. There is also an oral solution available if you have difficulty swallowing pills (DailyMed-a, 2020; DailyMed-b, 2020; Teva Pharmaceuticals USA, 2014). 

The typical starting dose is 25–50 mg, taken as needed, up to four times per day. Your healthcare provider may increase your dose based on your symptoms and side effects (Pfizer, 2019).  

Hydroxyzine warnings

Before starting hydroxyzine, be sure to review these warnings and speak with your healthcare professional about any concerns you have. 


Hydroxyzine can make you tired, dizzy, or confused, especially when you first start taking it. Older adults over the age of 65 may be more susceptible to these effects. Alcohol and other drugs that cause sedation can make this worse. Don’t drive or operate dangerous machinery until you know how hydroxyzine will affect you (Pfizer, 2019). 


You should not take hydroxyzine if you are allergic to cetirizine (brand name Zyrtec) or levocetirizine (brand name Xyzal) (Pfizer, 2019). 

Heart problems 

Rarely, hydroxyzine can affect the electrical activity in the heart and cause heart rhythm issues. This serious side effect tends to occur in people who already have risk factors for heart problems (Pfizer, 2019). Medications that affect the heart can also increase your risk. These include antiarrhythmics, antipsychotics, and certain antibiotics (Roden, 2016).

Let your healthcare provider know if you have a history of heart disease, all the medications you take, and if you or a family member have ever been diagnosed with a heart condition called long QT syndrome (Pfizer, 2019).

Other health conditions 

Certain medical conditions increase your chance of developing complications from hydroxyzine. Let your healthcare provider know if you have:

Pregnancy and breastfeeding 

It is not typically recommended to take hydroxyzine while pregnant. Animal studies have shown that using hydroxyzine early in pregnancy can increase the risk of birth defects (Pfizer, 2019). In rare cases, seizures have occurred in babies born to mothers who took hydroxyzine later in pregnancy (Serreau, 2005). 

If you decide to breastfeed your baby, your healthcare provider may recommend you stop your hydroxyzine. While the occasional small dose probably won't cause harm, larger or more consistent dosing could cause your baby to become drowsy or irritable. If you use hydroxyzine for allergy symptoms, newer antihistamines (like Claritin or Allegra) are preferred when breastfeeding (LactMed, 2021).  

Hydroxyzine interactions

Many drugs can interact with hydroxyzine. It's always best to check with your healthcare professional before starting anything new, even over-the-counter products. Here are some of the most common drug interactions to be aware of:

  • Alcohol and other sedating drugs: Alcohol and sedating drugs such as opioid pain medications (like Percocet or Oxycontin), sleeping pills (like Ambien or Lunesta), benzodiazepines (like Xanax or Klonopin), or a seizure medication called phenobarbital can interact with hydroxyzine and make you feel very tired. Your healthcare provider may prescribe lower doses of these medications if you need to take them while on hydroxyzine. Make sure to see how your medications affect you before driving or performing any activity that requires your full attention (Pfizer, 2019). 

  • Anticholinergic medications: Drugs that block a chemical in your body called acetylcholine can produce what are called anticholinergic effects, which include constipation, trouble urinating, dry mouth, dizziness, blurred vision, confusion, and a fast heart rate (Lieberman, 2004). Taking anticholinergic medications with hydroxyzine can increase your risk of developing these side effects. Many medications can have anticholinergic effects, but some common ones include certain inhalers (like Spiriva or Incruse Ellipta), drugs used for overactive bladder, antipsychotics (like clozapine), tricyclic antidepressants, and Parkinson’s disease medications. If you must take these medications with hydroxyzine, be sure to let your healthcare provider know if you develop any side effects (Horn, 2015). 

  • Potassium: If you take potassium tablets or capsules, talk with your healthcare provider about switching to the liquid form. Hydroxyzine can slow down your GI tract, causing the potassium tablet to sit in your stomach for a longer time. This can increase your risk of developing irritation or ulcers in your stomach or intestines (Mission Pharmacal Company, 2009).

  • COVID-19 vaccines: The Centers for Disease Control and Prevention (CDC) warns against taking antihistamines, like hydroxyzine, before receiving the COVID-19 vaccine. Antihistamines can make it difficult to determine if you are developing a serious allergic reaction to the vaccine and delay treatment for that reaction (CDC, 2021). 

  • Allergy skin testing: Antihistamines prevent your body from producing an allergic response. This can affect the results of allergy skin testing. If you’re scheduled for a skin test, ask your allergist when you should stop taking your hydroxyzine to ensure you get the most accurate results (Patel-b, 2019). 

If you’re struggling to get your anxiety under control, hydroxyzine may be able to help. Talk with your healthcare provider about your symptoms and your treatment options. Together, you can develop a plan that focuses on improving your mental health and quality of life.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

July 21, 2021

Written by

Christina Varvatsis, PharmD

Fact checked by

Steve Silvestro, MD

About the medical reviewer

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.