How Long Does Hydroxyzine Last In Your System And Will It Show Up On A Drug Test?

Last Updated: July 22, 2021

Authored by Dr. Ahmed Zayed

Reviewed by Michael Espelin APRN

First developed in 1955, Hydroxyzine is a common drug used to treat symptoms of allergies such as itching, running nose, and sneezing. It is an antihistamine that is administered orally or through injections. However, its side effects can be debilitating. So, it is important to speak with a medical doctor or pharmacist before administering the drug. But how long does Hydroxyzine last in the system? How does it even work? What is the half life of Hydroxyzine? And how long does Hydroxyzine take to work?

These topics and more would be thoroughly tackled in the ensuing paragraphs.

How Does Hydroxyzine Work?

Hydroxyzine, which is marketed under the brand names Vistaril and Atarax, is a drug whose importance to health can’t be understated. They are antihistamines that are used in the treatment of itches caused by allergic reactions. It prevents a substance release called histamine which is produced by the body’s immune system. Vistaril is also effective for the treatment of anxiety that is the most widespread mental disorder in the US. Hydroxyzine half life elimination for adults is around 20 hours thus it is used in preoperational procedures to sedate patients. Vistaril has its effect on the body by inhibiting H1 receptors. The H1 receptors mediate the body’s reaction to allergens. Histamines are chemical compounds produced by the immune system which are responsible for fighting allergens.

When the body is exposed to allergens, mast cells and basophils degranulate and release inflammatory mediators such as histamines. Vistaril acts as an inverse agonist to the histamines by connecting with the H1 receptors and, by doing so, slows down the activity of the receptor. Such an action of the medicine results in diminished symptoms manifestation. It also acts antagonistically to the 5-HT, muscarinic, and alpha- adrenoreceptors. The 5-HT receptor is responsible for the reception of serotonin. The ability to inhibit this reception gives the drug anxiolytic capabilities, thus it allows the use of Vistaril for anxiety.

Hydroxyzine Half-Life

Generally, the half-life of any medicine depends on the age group the patient belongs to. Often children happen to enjoy a shorter half-life of drugs compared to adults. Averagely, Hydroxyzine stays in the human body for 1-36 hours. For adults, the average half life of Hydroxyzine is around 20 hours while that of children is about 7 hours.

In the aged patients who may have a weak metabolic system, the Hydroxyzine half life is approximately 29 hours. Patients who suffer health problems like renal or hepatic impairment are likely to have a prolonged Vistaril half life.

Blue pills on the blue backgdound.

How Long Does Hydroxyzine Last?

Just like the Vistaril half life, the detection window for Hydroxyzine also varies, depending on the sample provided for testing; either urine, blood, saliva, or hair. Also, the detection time frames may be different for each patient

Blood Test

A drug test using a blood sample is very accurate, but an expensive one. The detection period for Atarax using blood tests is up to 27 hours.

Urine Test

A urine drug test can be done to detect the presence of the medicine. It is normally done by collecting a 30-60 mL urine sample of a patient and then evaluated in the laboratory. The detection window in the urine is up to 24 hours.

Saliva Test

The saliva test is one of Vistaril drug test methods with the shortest detection window. The detection window of the drug in the saliva is 8 hours. If tests are not carried out within 8 hours after use, traces of Vistaril will not be detected.

Hair Test

The detection period for drugs using hair as test samples is considered the longest. With the use of hair shafts, traces of Atarax consumed over a long period can be detected. The detection period in the hair is up to one month and remains detected for as long as three months, depending on the length of the hair shaft.

Does It Show Up on a Drug Test?

There’s a common misconception that Vistaril could turn false positive for benzos. Thus, patients on Vistaril are tempted to refrain from taking the drug before a drug test for fear of failing. So, does Hydroxyzine show up on a drug test? The short answer is no, it doesn’t. First, the chemical structure of both drugs; benzodiazepine (benzos) and Vistaril are not the same.

Also, there is a huge difference between Vistraril’s mechanism of action and that of benzos. So, even if large quantities of Vistaril are administered it is unlikely it would show up on a regular drug test. Finally, Vistaril doesn’t belong to the class of addictive or recreational drugs, thus most drug test kits are not designed to detect it. However, traces of the antihistamines can be detected in a specific Hydroxyzine drug test.

Does It Show Up on a Drug Test.

How Long Does Vistaril Take to Work?

Depending on Vistaril half life, the body’s metabolism, and route of administration, the histamine control drug can start working between 5 mins- 45 mins after intake. If the drug is administered orally, it can kick in after 30mins – 45 mins. However, it is even shorter (5mins – 10mins) when it is administered through injections. The medicine can then take up to 6 hours to feel its maximum effect before it begins to wear off. If it is employed to treat anxiety, then it would take hours for it to work. However, caution should be taken as the side effects of Vistaril can set in as quickly as when the drug starts working.

Factors That Influence How Long Vistaril Stays in the System

Generally, Hydroxyzine half life is around 20 hours, thus it should stay long in the system compared to other drugs. However, numerous factors affect the detection window for the medicine in the body. Results may vary between different people.

The Duration of the Drug’s Stay In the Body Depends On Several Factors:

  • Dose: The dosage determines how long the histamine control medication stays in the body. For instance, Vistaril 25 mg can be used for anxiety. It is a moderate dose that will leave the body in 20 hours. At the same time, consuming high doses of the medication (100 m) makes it tough for the body to flush it out of the system. It may even have a negative effect on your health.
  • Route of administration: The route of administration also plays a major role. For injections, Vistaril’s concentration level in the body is usually at its peak after 5-10 minutes of use, while it takes 30-45 minutes with tablets.
  • Dehydration :Exsiccosis leads to an increased concentration of the medication in the body. Since there is a low level of water in the system, dehydration can prolong the detection window considerably. In this case, Vistaril on a drug test can (with low probability) cause a false-positive result.
  • Length Of Use :It becomes very difficult for patients who have used Vistaril for an extended period of time to eliminate the drug. This increases the Hydroxyzine half life and leads to a longer detection window in the body.
  • Metabolism :The basal metabolic rate determines Hydroxyzine half life and how long it stays in one’s system, especially the saliva. The detection window is shorter for people with high BMRs, as they tend to excrete Atarax from their bodies faster.

Hydroxyzine Detox And Getting Vistaril Out Of The System Safely

Even though the medicine is not seen as an addictive drug capable of causing serious harm, there have been rare cases of severe side effects in patients who have used it. Therefore it is advisable that patients always follow the doctor’s prescription, to prevent Vistaril overdosing and avoid dangerous interactions. One way to get rid of the medication from your system is to undergo what is called medical tapering. It is a commonly prescribed method where the addict doesn’t abruptly stop taking the drug – this might send the abuser into shock and cause discomforting adverse effects.

Instead, the abuser is made to take the dosage in smaller quantities, reducing the quantity as each day passes. The addict is then monitored for any withdrawal symptoms. Tapering is gradually repeated until the addict can safely withdraw from the medication without any complications, and/or switch to alternatives to Vistaril under the supervision of a doctor.  Also, those addicted to the medication should seek treatment in an addiction treatment facility. With the help of professionals and carefully designed treatment programs for addicts, the patient will be able to break the addiction cycle and get back to a normal life.

Hope Without Commitment

Find the best treatment options. Call our free and confidential helpline

Most private insurances accepted

Marketing fee may apply

Page Sources

  1. Paton, D.M., Webster, D.R. Clinical Pharmacokinetics of H1-Receptor Antagonists (The Antihistamines). Clin Pharmacokinet 10, 477–497 (1985). https://doi.org/10.2165/00003088-198510060-00002,https://link.springer.com/article/10.2165/00003088-198510060-00002
  2. F. Estell R. Simons M.D, Keith J. Simons Ph.D., Evelyn M Frith R.T, The Pharmacokinetics and antihistaminic of the H1 Receptor Antagonist Hydroxyzine https://www.sciencedirect.com/science/article/abs/pii/009167498490486X
  3. The College of Psychiatric and Neurologic Pharmacists (CPNP) and the National Alliance on Mental Illness, Hydroxyzine (Vistaril, Atarax),(2019), https://www.nami.org/About-Mental-Illness/Treatments/Mental-Health-Medications/Types-of-Medication/Hydroxyzine-(Vistaril-Atarax)
  4. Drugs and Supplements Hydroxyzine (Oral Route),(2021).https://www.mayoclinic.org/drugs-supplements/hydroxyzine-oral-route/proper-use/drg-20311434?p=1
  5. Sonam Patel, Pravin Popatrao Kale, Veeranjaneyulu Addepalli, Amrita Sarkar, Jay Savai, Effect of a Combination of Duloxetine with Hydroxyzine on Experimental Models of Anxiety in Mice,(2015).https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4386125/
  6. Jason Schiffman M.D, M.A, M.B.A, Michael Davis M.D Ph.D., Joseph Pierre M.D, Scott C. Saunders, Hydroxyzine: Rational Choice for Inpatients with Insomnia, (2011). https://www.mdedge.com/psychiatry/article/64228/sleep-medicine/hydroxyzine-rational-choice-inpatients-insomnia
  7. Nagaraju Rajendraprasad, Kanakapura Basavaiah, Kanakapura B. Vinay, Optimized and Validated Spectrophotometric Methods for the Determination of Hydroxyzine Hydrochloride in Pharmaceuticals and Urine Using Iodine and Picric Acid, Journal of the Serbian Chemical Society, (2011). https://www.shd.org.rs/JSCS/Vol76/No11/10_4903_4228.pdf

Published on: March 11th, 2020

Updated on: July 22nd, 2021

About Author

Dr. Ahmed Zayed

Dr. Ahmed Zayed is a Bachelor of Medicine and Surgery. He is graduated from the University of Alexandria, Egypt. Dr. Ahmed Zayed has a passion for writing medical and health care articles and focuses on providing engaging and trustworthy information to readers.

Medically Reviewed by

Michael Espelin APRN

8 years of nursing experience in wide variety of behavioral and addition settings that include adult inpatient and outpatient mental health services with substance use disorders, and geriatric long-term care and hospice care.  He has a particular interest in psychopharmacology, nutritional psychiatry, and alternative treatment options involving particular vitamins, dietary supplements, and administering auricular acupuncture.