Hydroxyzine is an antihistamine prescribed primarily for two conditions: anxiety and itching caused by allergic reactions. It works by blocking histamine receptors in the body, which reduces allergic symptoms, and its strong sedating properties make it useful for calming anxiety and tension. The drug starts working within 15 to 60 minutes and lasts about 4 to 6 hours per dose.
FDA-Approved Uses
Hydroxyzine has two official, FDA-approved purposes. The first is relieving anxiety and tension, where it’s used either on its own or alongside treatment for other medical conditions where anxiety is a factor. The second is managing itching from allergic conditions like hives, eczema, and contact reactions to irritants. It’s also approved for use before surgery to help patients feel calm and sleepy.
Beyond these approved uses, doctors commonly prescribe hydroxyzine off-label for insomnia and nausea. Its sedating effect makes it a popular choice when a non-addictive sleep aid is needed, particularly in settings where controlled substances are less desirable.
How It Works
Hydroxyzine is one of the most potent first-generation antihistamines available. It blocks H1 receptors, which are the same receptors that trigger itching, hives, sneezing, and other allergy symptoms when histamine is released in the body. Blocking these receptors also produces significant sedation, which is what gives hydroxyzine its calming, anxiety-reducing effect.
The drug also has anticholinergic properties, meaning it blocks a chemical messenger called acetylcholine. This is responsible for some of its side effects (dry mouth, constipation) but also contributes to its sedating and anti-nausea effects.
Hydroxyzine for Anxiety
Hydroxyzine is frequently used as an alternative to benzodiazepines for anxiety, both in hospital and outpatient settings. A Cochrane review of 39 studies on generalized anxiety disorder found that hydroxyzine was more effective than placebo and comparable to benzodiazepines and buspirone in reducing anxiety symptoms. The key advantage is that hydroxyzine does not carry the same risk of dependence, abuse, or misuse that benzodiazepines do.
That said, hydroxyzine has its own limitation for long-term anxiety management: patients tend to develop tolerance over time, meaning the calming effect can weaken with continued use. This makes it better suited for short-term or as-needed use rather than as a long-term daily treatment. For ongoing anxiety, SSRIs are generally considered the first-line option.
Atarax vs. Vistaril
Hydroxyzine comes in two chemical forms. Hydroxyzine hydrochloride was sold as Atarax, and hydroxyzine pamoate was sold as Vistaril. A widespread belief in clinical practice holds that the hydrochloride form is better for itching and the pamoate form is better for anxiety. There is no evidence to support this distinction. The two forms are clinically interchangeable, and the tradition appears to be based on how the drugs were originally marketed rather than any meaningful difference in how they work in the body.
Common Side Effects
The most noticeable side effect is drowsiness, which can be significant. Because hydroxyzine is a first-generation antihistamine, it crosses into the brain much more readily than newer antihistamines like cetirizine or loratadine. Other common side effects include dry mouth and throat, dizziness, blurred vision, constipation, headache, and impaired coordination. Some people also experience a rapid heartbeat or stomach discomfort.
These effects are strongest when you first start taking the medication and may lessen somewhat over time. Driving or operating machinery can be risky while the drug is active, especially during the first few hours after a dose.
Cardiac Risk and Dose Limits
At higher doses, hydroxyzine can affect the heart’s electrical rhythm by prolonging what’s called the QT interval, which in rare cases can trigger a dangerous heart rhythm called torsade de pointes. The maximum recommended dose is 100 mg per day. The European Medicines Agency has recommended that hydroxyzine be avoided entirely in people with existing risk factors for heart rhythm problems or in those taking other medications that can prolong the QT interval.
This cardiac concern is one reason hydroxyzine doses tend to be conservative in practice, even though older prescribing guidelines sometimes listed higher amounts.
Risks for Older Adults
The American Geriatrics Society lists hydroxyzine on the Beers Criteria, a widely used guide that flags medications considered potentially inappropriate for people over 65. The recommendation is to avoid it in this age group. The reasons are straightforward: the body clears the drug more slowly with age, amplifying both the sedation and the anticholinergic effects. In older adults, this translates to a higher risk of confusion, falls, constipation, urinary retention, and dry mouth. If hydroxyzine must be used in someone over 65, the recommended ceiling is 50 mg per day rather than the standard 100 mg.
Stopping Hydroxyzine
Hydroxyzine is not considered addictive in the way benzodiazepines or opioids are, but stopping it abruptly after regular use can produce withdrawal-like symptoms. These may include nausea, headaches, dizziness, disrupted sleep, sweating, fatigue, and general body aches. Rebound effects are also possible, where the condition the drug was treating (particularly anxiety or insomnia) temporarily returns with greater intensity than before treatment. Tapering the dose gradually rather than stopping all at once helps minimize these effects.