How Long Does Hydroxyzine Last?
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Pouring prescription medicine into handMedically reviewed by Femi Aremu, PharmD
Hydroxyzine is a generic prescription medication that is available in two formulations:
Hydroxyzine hydrochloride, also known as Atarax, a brand-name medication no longer made in the U.S.
Hydroxyzine pamoate, also known by the brand name Vistaril
Hydroxyzine is an antihistamine used to treat various conditions, such as the following:
Itching due to allergies
Many people who take hydroxyzine wonder how long each dose lasts. This article will answer that question and provide other information about this medication.
How Long Does Hydroxyzine Last?
Hydroxyzine hydrochloride (HCL) and hydroxyzine pamoate are both considered to be equal in terms of dosage and how they are absorbed.
A dose of the medication starts to work as soon as 15 to 60 minutes and lasts up to four to six hours. One clinical study found that a dose of hydroxyzine reaches its maximum effect in about two hours.
A medication's half-life is when it takes about half of the medication to leave the body. It takes about five half-lives for a medication dose to leave the body. The half-life of both forms of hydroxyzine ranges from 14 to 25 hours. Thus, the medication can remain in the body for about 70 to 125 hours (five half-lives) after the last dose.
However, the effects of a dose may only last up to about six hours. If you keep taking doses of hydroxyzine as prescribed (usually every six to eight hours), some medicine will remain in your system until 70 to 125 hours after you take the last dose.
The prescribing information also notes that hydroxyzine can suppress inflammation and itching for up to four days.
How Long Does Hydroxyzine Last - Summary
The numbers above can be confusing, so here is a quick summary: A dose of hydroxyzine can start working within 15 to 60 minutes and reaches its maximum effect in about two hours.
The effects of a dose wear off after about six hours, and the medicine may be prescribed to be taken several times daily. However, the medicine does not completely leave your body for up to 125 hours (five days) after the last dose is taken.
What Are Common Dosages of Hydroxyzine?
Hydroxyzine is available in the following forms:
Oral tablets (hydroxyzine HCL): 10 milligrams (mg), 25 milligrams, and 50 milligrams
Oral capsules (hydroxyzine pamoate): 25 milligrams, 50 milligrams, and 100 milligrams
Oral solution: 10 milligrams per 5 milliliters (mL)
Injection: 25 milligrams per milliliter, 50 milligrams per milliliter
Common dosages include the following:
Anxiety (adults): 50 to 100 milligrams by mouth every six hours as needed or a 50 to 100-milligram injection every four to six hours as needed
Anxiety (children): Dosage depends on age and weight
Itching/hives (adults): 25 milligrams by mouth every six to eight hours as needed
Itching/hives (children): Dosage depends on age and weight
Sedative before anesthesia (adults): 25 to 100 milligrams injected once if needed or 50 to 100 milligrams orally once if needed
Sedative before anesthesia (children): Dosage depends on a person's weight
Some healthcare providers prescribe hydroxyzine off-label. Off-label prescribing is when a healthcare provider prescribes a medication for a use that the Food and Drug Administration (FDA) has not approved. However, research shows the medication may help certain conditions.
Insomnia: Because of its sedating effect, hydroxyzine is sometimes prescribed off-label for adults with insomnia (difficulty falling and/or staying asleep). Experts recommend this only as a short-term treatment because evidence is not conclusive that this treatment is safe and effective, especially for long-term use. The off-label adult dose for insomnia is generally 50 to 100 milligrams by mouth, taken 30 to 60 minutes before bedtime. A pediatric dose is not recommended for off-label use for insomnia.
Nausea and vomiting: Hydroxyzine is FDA-approved for use in adults with nausea and vomiting in its injectable form with an adult dosage of 25 to 100 milligrams injected every four to six hours as needed. It is sometimes prescribed off-label in its oral form for nausea and vomiting. However, hydroxyzine is not used for nausea and vomiting that is associated with pregnancy. The adult dose of oral hydroxyzine for nausea and vomiting is generally prescribed as 25 to 100 milligrams by mouth every six to eight hours as needed. The pediatric dose of oral hydroxyzine depends on age and weight.
Seasonal allergies: Hydroxyzine is sometimes used off-label to treat seasonal allergies. However, due to side effects of dry mouth and drowsiness, it's not commonly used for this reason.
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Pouring prescription medicine into handWhat Are the Side Effects of Hydroxyzine?
Hydroxyzine is a first-generation antihistamine. These "older" antihistamines cross the blood-brain barrier. This causes side effects (such as drowsiness and impaired coordination) even at normal doses. These side effects can be troublesome in some people, like older adults or those with certain medical conditions.
Common side effects of hydroxyzine may include, but are not limited to, the following:
Dry mouth
Drowsiness
Dizziness
Weakness
Impaired coordination
Speech problems
Headache
Agitation
Bitter taste in the mouth
Nausea
Call your healthcare provider right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you have a medical emergency.
Serious side effects and their symptoms can include the following:
Anaphylaxis (severe allergic reaction): Get emergency medical help if you have urticaria (hives), difficulty breathing, or swelling of the face, lips, tongue, or throat
QT prolongation and torsades de pointes: a heart rhythm disorder that may cause fast and chaotic heartbeats
Report Side Effects
Hydroxyzine may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication. If you experience a serious side effect, you or your healthcare provider may send a report to the FDA MedWatch Adverse Event Reporting Program or by phone (800-332-1088).
Who Should Not Take Hydroxyzine?
Hydroxyzine is not appropriate for everyone. Before taking hydroxyzine, tell your healthcare provider about your:
Medical conditions
Medical history
Family history
You should not take this medication if you are allergic to hydroxyzine or any of the inactive ingredients in hydroxyzine.
You should not take hydroxyzine if you are allergic to the following medications because hydroxyzine breaks down in the body into the following products:
Cetirizine, brand name Zyrtec
Levocetirizine, brand name Xyzal
People with long QT syndrome also should not take hydroxyzine.
In some people, hydroxyzine may be prescribed with caution only if the healthcare provider determines it is safe. Some examples include the following:
People with heart or heart rhythm conditions
People who take other medications that cause central nervous system (CNS) depression (slowing down of the nervous system)
People who consume alcohol
Older adults
People with asthma
Others
What Are Interactions With Hydroxyzine?
Tell your healthcare provider about all your medicines, including prescription and over-the-counter (OTC) medicines, vitamins, and supplements.
While taking hydroxyzine, do not start any new medications without approval from your healthcare provider.
Food and drink interactions include the following:
Grapefruit: If you consume grapefruit or grapefruit juice, check with your healthcare provider before combining it with hydroxyzine. Large amounts of grapefruit juice combined with hydroxyzine could cause heart rhythm problems.
Alcohol: Avoid alcohol while taking hydroxyzine, as the combination could worsen side effects and cause impairment, slowed breathing, and other complications.
Some drug interactions include, but are not limited to:
Hydroxyzine is known as a CNS depressant because it slows down and sedates the nervous system. Hydroxyzine should not be combined with CNS depressants, such as medicines for sleep, pain, anxiety, depression, seizures, muscle spasms, or alcohol.
Hydroxyzine can interact with certain antibiotics, heart rhythm medicines, antipsychotic drugs, and medicines used to treat cancer, malaria, HIV, and AIDS.
Because many interactions can potentially occur with hydroxyzine, talking to your healthcare provider about drug interactions is essential.
Drug Interactions
This is not a full list of drug interactions. Other drug interactions may occur with hydroxyzine. Consult your healthcare provider for more information about drug interactions and how they may affect you.
Hydroxyzine Alternatives
Sometimes, hydroxyzine is not a first-choice or appropriate drug in some people. For example, as a first-generation antihistamine, it causes many side effects.
Newer antihistamines like Allegra (fexofenadine) and Xyzal (levocetirizine) may still cause some drowsiness, however, not to the extent of first-generation antihistamines. And these newer antihistamines cause fewer side effects in general.
Also, hydroxyzine may cause more side effects and not be appropriate in older adults. This is due to the potential increased risk of the following:
Falls
Delirium (a mental state of confusion and disorientation)
Dementia (impaired brain functions, such as memory loss)
These can even occur in younger adults as well. Therefore, for many people, hydroxyzine may not be the best choice of medication. Another medication may be considered.
Let's talk more about other options for insomnia and allergies.
What Are the Alternatives for Insomnia?
If you have trouble falling asleep and/or staying asleep, there are other options you can try. For example:
Sleep in a cool, dark, quiet room without distractions like TVs and phones.
Keep a consistent sleep schedule. Go to sleep and wake up around the same time every day, including weekends. Try to avoid afternoon naps, which make it more difficult to fall asleep later.
Avoid stimulants like caffeine and alcohol up to eight hours before bed.
Avoid eating late dinners.
Avoid drinking liquids too close to bedtime, which may make you get up to use the bathroom.
Exercise regularly, but finish your exercise several hours before bed. Consult your healthcare provider before beginning a new exercise program.
Manage stress with therapy, relaxation, meditation, yoga, acupuncture, or other healthy ways.
Talk to your healthcare provider about trying a dietary supplement like magnesium, melatonin, or prescription medication.
What Are the Alternatives for Allergies?
If you have allergies, you can see an allergist who can help you identify your triggers and find ways to avoid them. Some tips include the following:
Keep an eye on weather reports to monitor pollen and mold counts, staying inside when necessary.
Close windows and doors at home, and keep windows closed in the car when your allergies are bothering you.
When you come in from spending time outside, take a shower right away. Wash your body and hair thoroughly, and put on clean clothes.
Wear a mask when working outdoors.
Consider using an air purifier, especially in your bedroom.
Make sure carpets are frequently vacuumed during the height of allergy season. Consider asking someone to help you do this if this irritates your allergies.
There are many other approaches available to treat allergy symptoms, including the following:
Decongestants for a stuffy nose
Nasal steroid sprays such as Flonase
Antihistamines that cause less drowsiness, such as Xyzal (levocetirizine)
Steroid creams or ointments for itchy skin
Eye drops
You can ask your healthcare provider or pharmacist which medicine or combination of medicines would be best for you based on your symptoms and other medical conditions you have.
Summary
Hydroxyzine is a medication used to treat insomnia, anxiety, and itching.
A dose of hydroxyzine may start working as quickly as 15 to 60 minutes.
It reaches the maximum effect in about two hours.
Due to its long half-life, hydroxyzine can stay in your body for up to 125 hours after the last dose.
Because it causes sedation and many other side effects, hydroxyzine is not always the first choice of drug.
As always, it is best to discuss your medical care with your healthcare provider, who can give you personalized medical advice based on your medical history.
Frequently Asked Questions
How long does hydroxyzine last?
A dose of hydroxyzine can start working within an hour and reaches its maximum effect in about two hours. The way it is dosed depends on the person's age and symptoms. Although it can last a long time until it completely leaves the body, its effects wear off after about six hours, and the medicine can be dosed up to three or four times daily, depending on the individual.
How long does hydroxyzine last for anxiety?
Hydroxyzine is generally dosed up to four times daily as needed for anxiety. It can start working within an hour, and it reaches its maximum effect in about two hours, but the effects may wear off after about six hours, even though the medication takes much longer to clear the body completely. Your healthcare provider can determine the appropriate dosing.
Is hydroxyzine habit forming?
Hydroxyzine is not a controlled substance. It does not have a risk for abuse and dependence.
