Hydroxyzine (Atarax, Vistaril): Uses & Side Effects
What it is
First-generation antihistamine
Hydroxyzine is an effective prescription antihistamine for itching and anxiety, but its sedation, anticholinergic effects and heart-rhythm cautions make it a poor fit for some people, especially older adults.
Hydroxyzine has been used for decades. It comes as hydroxyzine hydrochloride tablets and syrup and hydroxyzine pamoate capsules (Vistaril); the original Atarax brand is no longer the common name in US pharmacies, but generic versions are widely available. It is used for itching from hives, eczema and contact dermatitis, for anxiety and tension, and as a sedative before or after procedures. Unlike Zyrtec or Claritin it is not sold over the counter, and it causes much more drowsiness. Its active breakdown product is cetirizine.
This is a general medication overview, not medical advice or a prescription. A pharmacist or your prescriber can confirm what's right for you.
Key facts
Hydroxyzine is a prescription antihistamine used for itching from allergic conditions and for anxiety.
The hydroxyzine label warns of QT prolongation and says it should not be used in early pregnancy.
Drowsiness is the most common side effect of hydroxyzine; avoid alcohol while taking it.
How Hydroxyzine works
Hydroxyzine blocks histamine H1 receptors in the skin and elsewhere, which reduces itching and hives. As a first-generation antihistamine it crosses easily into the brain, where blocking H1 receptors causes sedation and a calming effect; this is why it is also used for anxiety. It also has anticholinergic effects, such as dry mouth. The body converts part of it into cetirizine.
What it's used for
Hydroxyzine is used to treat the conditions below. This isn't a full list of every off-label use — your prescriber can tell you if it fits your situation.
Itching from chronic hives (urticaria)
Itching from atopic dermatitis (eczema) and contact dermatitis
Short-term relief of anxiety and tension
Sedation before or after medical or dental procedures
Dosage basics
These are general reference points, not a prescription. The right dose depends on your age, other medicines, and health — always follow the product label or your prescriber.
Hydroxyzine is prescription-only, and the dose depends on the reason it is prescribed, your age, and your health. Older adults usually start at a lower dose. Do not take more than prescribed or combine it with other sedating medicines without your prescriber's approval. Follow the label and your prescriber's instructions exactly.
Don't start, stop, or change a dose based on this page. Read the label that comes with the product and confirm with a pharmacist or prescriber first.
Side effects to know
Most people tolerate it well, but every medicine has trade-offs. Common effects are usually mild; the serious ones below are rare but need prompt attention.
Usually mild
Common side effects
- Drowsiness and sedation
- Dry mouth
- Headache
- Dizziness
- Confusion, especially in older adults
Rare — seek care
Serious side effects
- Heart rhythm changes (QT prolongation); seek care for a fast or irregular heartbeat or fainting
- Seizures or tremor (rare)
- Severe skin reaction with fever and widespread pustules (rare)
- Allergic reaction: swelling of the face or throat, trouble breathing
Stop the medicine and get medical help right away for any serious reaction — trouble breathing or fast facial/throat swelling is a 911 emergency.
Interactions & cautions
Some medicines, conditions, and habits change how this drug works — or how safe it is. This isn't exhaustive, so share your full medication list with a pharmacist.
Interacts with
Alcohol, opioids, benzodiazepines, sleep aids and other sedatives
Greatly increases drowsiness and slowed breathing or reactions. Avoid alcohol; doses of other sedatives may need to be lowered.
Medicines that prolong the QT interval (for example some antiarrhythmics, antibiotics, antidepressants and antipsychotics)
Raises the risk of dangerous heart rhythm changes. Tell your prescriber about every medicine you take.
Other anticholinergic medicines
Adds dry mouth, constipation, urinary retention and confusion.
Other antihistamines, including cetirizine and levocetirizine
Doubles antihistamine effects and side effects.
Use caution or avoid if
- Early pregnancy: the label says hydroxyzine should not be used
- Known QT prolongation or certain heart rhythm problems
- Allergy to hydroxyzine, cetirizine or levocetirizine
- Adults 65 and older: first-generation antihistamines are on the AGS Beers Criteria list of potentially inappropriate medicines because of sedation and confusion
- Breastfeeding, glaucoma, or trouble urinating: discuss with your doctor first
What most pages leave out
Availability
PrescriptionHydroxyzine requires a prescription in the US. It is available as generic hydroxyzine hydrochloride tablets and syrup and hydroxyzine pamoate (Vistaril) capsules.
We flag this so you can make an informed choice — a pharmacist can tell you what's stocked and appropriate where you are.
Frequently Asked Questions
Yes. Hydroxyzine is a first-generation antihistamine, the older group that also includes diphenhydramine. These drugs cross into the brain easily, which is why hydroxyzine causes noticeable drowsiness. Second-generation antihistamines such as cetirizine, loratadine and fexofenadine cause much less sedation.
No. Hydroxyzine is first-generation. The body does turn part of it into cetirizine, which is a second-generation antihistamine, but hydroxyzine itself is the sedating older type. That is part of why it is used for anxiety and sleep before procedures, while cetirizine is sold as a daytime allergy pill.
No, not in the US. Hydroxyzine needs a prescription. Over-the-counter antihistamines for itching include cetirizine, loratadine, fexofenadine and diphenhydramine. If you think you need hydroxyzine for itching or anxiety, a doctor can decide whether it is appropriate for you.
Both contain hydroxyzine but in different salt forms. Atarax was the brand name for hydroxyzine hydrochloride, which comes as tablets and syrup. Vistaril is hydroxyzine pamoate, sold as capsules. They work the same way and are used for the same conditions; dosing is adjusted for the form.
Hydroxyzine is used to relieve itching from allergic skin conditions such as hives, eczema and contact dermatitis, and for short-term relief of anxiety and tension. It is also used to help people relax and feel sleepy before or after medical procedures. It is not a first choice for everyday hay fever because of its sedation.
Hydroxyzine has antiemetic properties, and the injectable form has been used to control nausea and vomiting in medical settings. Oral hydroxyzine is not mainly prescribed for nausea, and other medicines are usually preferred. Ask your doctor before using it for nausea.
Yes. Drowsiness is the most common side effect of hydroxyzine, and it is often used partly for its calming effect. Do not drive or operate machinery until you know how it affects you, and avoid alcohol.
It needs caution. The American Geriatrics Society Beers Criteria list first-generation antihistamines like hydroxyzine as potentially inappropriate for adults 65 and older because they can cause confusion, falls, constipation and urinary retention. Doctors often prefer other options or lower doses in older patients.
It can in some people. Hydroxyzine can prolong the QT interval on an ECG, which rarely leads to a dangerous irregular heartbeat. The risk is higher with other QT-prolonging medicines, low potassium or magnesium, or existing heart disease. Get medical help right away for a racing or irregular heartbeat or fainting.
Both are first-generation antihistamines that relieve itching and cause drowsiness. Hydroxyzine is often prescribed for itching from hives and eczema because it lasts longer and is well studied for that use, but it is prescription-only. Neither is a good daytime choice if drowsiness is a problem.
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This content is for general informational purposes only and is not medical advice, a prescription, or a substitute for professional judgment. It does not account for your health, other medications, or dose, and drug information changes over time. Availability, approval status, and formulations differ by country. Always read the product label and ask your pharmacist or prescriber before starting, stopping, or changing any medication. Curex offers at-home allergy testing and immunotherapy for confirmed environmental allergies; it does not sell or provide the medication reviewed on this page and does not provide emergency care.