Drugs Q & A

How Long Does Hydroxyzine Stay In Your System?

What is hydroxyzine?

Hydroxyzine is a prescription medication classified as an antihistamine. It was first made by Union Chimique Belge in 1956 and was approved for sale by Pfizer in the United States later that year. It’s approved by the Food and Drug Administration (FDA) for the following uses in adults and children:

•          Relieve anxiety symptoms. Hydroxyzine may also be used with other medications to treat anxiety. But it isn’t known how well this drug works for treating anxiety long-term.

•          Provide sedation (a relaxed state, for relief of tension and anxiety) before surgery or another medical procedure. For this use, hydroxyzine is what’s known as a premedication. This is a medication given before surgery to help relieve certain symptoms, such as anxiety.

•          Relieve skin itchiness caused by atopic dermatitis. With atopic dermatitis, you have dry, itchy skin caused by too much inflammation.

Hydroxyzine oral tablets are available in the following strengths: 10 milligrams (mg), 25 mg, and 50 mg. Hydroxyzine also comes in other forms. For example, hydroxyzine pamoate is available in capsule form.

How hydroxyzine works

Hydroxyzine is in a class of medications called antihistamines. It works by blocking the action of histamine a substance in the body that causes allergic symptoms. It also works by decreasing activity in the brain. Hydroxyzine is used in adults and children to relieve itching caused by allergic skin reactions. It is also used alone or with other medications in adults and children to relieve anxiety and tension.

How should I take hydroxyzine?

Hydroxyzine comes as capsules, tablets, syrup, and suspension to take by mouth. It usually is taken three or four times a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand.

Typical dosing for hydroxyzine


•          Adults: The typical dose is 25 mg by mouth three to four times daily.

          Children over 6 years old: The typical dose is 50 to 100 mg by mouth daily, given in separate doses throughout the day.

•          Children under 6 years old: The typical dose is 50 mg by mouth daily, given in separate doses throughout the day.


•          Adults: The typical dose is 50 mg to 100 mg by mouth four times daily.

•          Children over 6 years old: The typical dose is 50 mg to 100 mg by mouth daily, given in separate doses throughout the day.

          Children under 6 years old: The typical dose is 50 mg by mouth daily, given in separate doses throughout the day.

Hydroxyzine is also available as an injection given into the muscle by a healthcare provider

Take hydroxyzine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Shake the suspension well before each use to mix the medication evenly.

How long does hydroxyzine stay in your system?

There are several factors that come into play when estimating how long hydroxyzine will stay in your system because every patient has physiology unique to them. Here are some major factors you should consider when trying to understand how long hydroxyzine will stay in your body:

•        Age: Typically, the younger you are, the more efficient your body functions are. The more efficient your body functions, the faster hydroxyzine will be removed from your system.

•     Amount: The higher the dose of hydroxyzine you have been taking, the longer Hydroxyzine will take to be removed from your system.

•        Genetics: Genes predispose people to different metabolic functions, which is a key factor in how your body processes medications like hydroxyzine. For this reason, your genetic makeup comes into play when estimating how long Hydroxyzine will remain in your system.

•        Kidney and liver functions: The liver and kidneys eliminate everything you ingest, and hydroxyzine is no exception. If your liver or kidneys are damaged, it will most likely take longer for your body to remove the hydroxyzine from your system.

•        Metabolism: Your metabolism determines how quickly you process foods, liquids, and drugs such as hydroxyzine. If your metabolism is slow, it will take longer for your body to process and eliminate hydroxyzine from its system than someone with a fast metabolism.

•        Usage frequency: The longer you have been taking hydroxyzine, the longer it will remain in your system. For example, it will take longer for someone who has taken hydroxyzine for several years to remove hydroxyzine from the body than someone who has only been taking hydroxyzine for a few months.

Hydroxyzine can be administered orally or via intramuscular injection. When given orally, hydroxyzine is rapidly absorbed from the gastrointestinal tract. The effect of hydroxyzine is notable in 30 minutes. The elimination half-life of hydroxyzine ranges from 7 to 20 hours. The half-life of a drug is the time it takes for the amount of a drug’s active substance in your body to reduce by half. About 94 to 97% of a drug will have been eliminated after 4 to 5 half-lives. Thus, it follows that after 4 to 5 half-lives, the plasma concentrations of a given drug will be below a clinically relevant concentration and thus will be considered eliminated.

Generally, it takes between 100 hours (about 5 days) depending on many other factors to remove hydroxyzine from your system after you stop taking it. However, consuming some types of foods and beverages can increase the amount of time it takes for your body to eliminate the drug from your system and the risk of side effects. It is important to note that the elimination of hydroxyzine in children is much faster compared to adults.

How long does hydroxyzine last?

The effects of hydroxyzine will last as long as the drug remains in your system but will continue to wane as the drug is eliminated from your body which can take up to 5 days. Hydroxyzine can cause side effects, such as drowsiness, fatigue (lack of energy), being unable to concentrate, or feeling confused. These side effects can affect the way you feel.

Hydroxyzine may interact with other medications, such as central nervous system depressants (e.g., alcohol, sedatives) or drugs that cause QT prolongation (a heart rhythm disorder). It’s crucial to inform your healthcare provider about all the medications, supplements, and herbal products you are taking to avoid potential interactions.


Dr. Oche Otorkpa PG Cert, MPH, PhD

Dr. Oche is a seasoned Public Health specialist who holds a post graduate certificate in Pharmacology and Therapeutics, an MPH, and a PhD both from Texila American University. He is a member of the International Society of Substance Use Professionals and a Fellow of the Royal Society for Public Health in the UK. He authored two books: "The Unseen Terrorist," published by AuthorHouse UK, and "The Night Before I Killed Addiction."
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