OverviewDosageSide EffectsInteractionsHalf-Life

Generic Name: Hydroxyzine
Brands: Vistaril (hydroxyzine pamoate), Atarax (hydroxyzine hydrochloride)
Class: First generation antihistamines
Availability: Only available by prescription
Molecular Formula: C21H27ClN2O2 · 2HCl
Substance UNII: M20215MUFR

What is Hydroxyzine?

Hydroxyzine is a first-generation antihistamine, and it is currently sold under the brand name Vistaril (hydroxyzine pamoate). Currently, Atarax (hydroxyzine hydrochloride) is not available in the United States.

Although hydroxyzine is classified as an anti-allergy medicine, it also possesses sedative, antiemetic (anti-nausea), antispasmodic (anti-spasm), and anticholinergic (blocks the actions of the neurotransmitter acetylcholine) properties.

What is Hydroxyzine Used For?

Hydroxyzine is typically used to manage symptoms of various allergic conditions that cause itchiness. For example, it can be used for chronic urticaria (hives), atopic and contact dermatoses (disease of the skin), or histamine-mediated pruritus (itching).

But hydroxyzine also has other uses. 

Many use it to relieve anxiety and tension associated with psychoneurosis (neurosis), and others use it as an adjunct medicine when an organic disease causes anxiety.

Hydroxyzine is furthermore used to help manage withdrawal symptoms in alcoholic patients; these symptoms may include anxiety and agitation. It is also used effectively to treat withdrawal symptoms associated with a variety of opioids.

Hydroxyzine additionally has sedative properties. Therefore, because it can help feeling sleepy and relaxed before and after surgery, it is sometimes used as a premedication and following general anesthesia. 

Lastly, hydroxyzine can help manage nausea and vomiting, and possibly other off label uses.

How Does Hydroxyzine Work?

Researchers have not fully understood how hydroxyzine works in the human body and mind, but many agree that it affects how two chemicals in the body (histamine and serotonin) act.

Histamine is a chemical that the body makes during an allergic reaction. As an antihistamine, hydroxyzine therefore works by blocking histamine

Serotonin is a chemical that affects mood. Because of its unique effect on this neurotransmitter, hydroxyzine can be used in the treatment of anxiety. While this medication is quite versatile and can help treat many different types of anxiety disorders, it is used most often for generalized anxiety disorder (GAD).

How Long Does it Take for Hydroxyzine to Work?

After oral administration, hydroxyzine is rapidly absorbed and its effects can be observed within 15 to 30 minutes. Maximal clinical actions develop within 2 hours, and its effect last for 4 to 6 hours.

Please see our hydroxyzine half-life page for more information.

Do Not Use Hydroxyzine If:

There are several situations where this medication may not be the right choice for you.

According to the U.S. National Library of Medicine, the following should not use hydroxyzine:

  • people with known hypersensitivity to hydroxyzine hydrochloride products
  • people with known hypersensitivity to cetirizine hydrochloride or levocetirizine hydrochloride 
  • people who have shown a previous hypersensitivity to any component of this medication
  • people with a prolonged QT interval (QT interval is the time taken by the heart to recharge in between beats) 
  • pregnant women

Please note that this list may not be complete, and there may be other situations where hydroxyzine use is not advisable.

Disclaimer: this article does not constitute or replace medical advice. If you have an emergency or a serious medical question, please contact a medical professional or call 911 immediately. To see our full medical disclaimer, visit our Terms of Use page.

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