In this complete guide to hydroxyzine, you’ll learn what this prescription antihistamine is and why it is used to treat allergies, itching, anxiety, sleep problems, and nausea or vomiting. We explain its brand names, available forms and strengths, recommendeddosage, important warnings and side effects, potential drug interactions, and steps to take in case of an overdose or emergency. You will learn how long to take hydroxyzine safely, compared to all the other antihistamines, how much it will cost, where to obtain it, and the key research and studies in order to use it. Certain responses to all your most basic questions enable you to use hydroxyzine safely and effectively.
Hydroxyzine is an antihistamine medication that doctors use to induce relieve allergy symptoms, suppress anxiety, relieve itching, promotes sleep, and prevent nausea or vomiting.
Through sedation and antiallergic effects, the medication is highly under the three phases of the triad treatment: psychiatric disorder, allergic therapy, and preoperative condition.
What is Hydroxyzine?
Hydroxyzine is given to patients to relieve chronic allergic symptoms like itching and hives, provide sedation of tension states or anxiety, and help with short-term insomnia or pre-operative sedation.They also use hydroxyzine to prevent nausea and vomiting, such as in motion sickness and postoperative nausea.
Hydroxyzine is a first-generation antihistamine and a histamine H1 receptor blocker that reduces allergy symptoms. Some of the new non-sedative antihistamines do not cross it, but hydroxyzine crosses the blood–brain barrier freely and that is why it has calming as well as sedative effects.
This combination of anti-anxiety and anti-itch properties makes hydroxyzine unique among other allergy medications.
A randomized controlled trial (European Neuropsychopharmacology, 2002) also confirmed hydroxyzine to be better than placebo by significant margin in anxiety rating scores among patients with generalized anxiety disorder.
rand Names and Forms
Hydroxyzine is marketed in the global market by various pharma companies under various brand names such as Atarax, Vistaril, Hyzine, Restall, etc., and various local brand names.
It is available in tablet, capsule, syrup, and injectable forms (all of which are stocked in hospitals).
Generic hydroxyzine would contain the same active ingredient as brand hydroxyzine but at a lower cost.
Mechanism of Action: How Hydroxyzine Works
Hydroxyzine blocks the action of histamine, a chemical released during allergic reactions.
It reduces itching, redness, swelling, and other allergic effects through its action upon H1 receptors.
It also impacts some of the brain chemicals such as some acetylcholine and serotonin and produces calming effect with insomnia and anxiolysis.
Due to how potent it is on action on the central nervous system, hydroxyzine is most likely to cause sedation compared to second-generation antihistamines such as cetirizine or loratadine.
Drug Design, Development and Therapy (2015) feature sedative effect to hydroxyzine as one of the mechanisms by which it impacts the central nervous system.
Available Forms and Strengths
Hydroxyzine comes in a range of strengths in a few forms to make it easy to give:
- Tabs or Capsules (10 mg, 25 mg, 50 mg)
- Oral Syrup (10 mg/5 mL)
- Intramuscular Injection (Hospital Use)
Available for purchase under the brand names Atarax, Vistaril, and generic hydroxyzine hydrochloride/pamoate.
Dosage and Administration
Dosage is dependent on the condition treated, age, and history.
- Anxiety: 50–100 mg orally upto 4–6 hours
- Allergies/Itching: 25 mg orally 3–4 times a day
- Sedation (pre-operation): 50–100 mg by injection or orally
- Children (over the age of 6): 50–100 mg/day divided into smaller doses
The hydroxyzine can either be taken on an empty stomach or with food. Directives should always be followed.
Don’t take more than your doctor has recommended, and don’t take with other sedatives unless on a medical advice.
A 2021 JAMA Psychiatry clinical practice guideline reiterates hydroxyzine as an initial non-addicting drug to treat acute anxiety.
Precautions and Contraindications
Take hydroxyzine with caution if you:
- Are prone to abnormal heart rhythm or QT prolongation.
- Are pregnant or breastfeeding, particularly in the first trimester.
- Have glaucoma, enlarged prostate, or respiratory conditions like severe asthma.
- Are a senior, as confusion and sedation can be more strong.
Since hydroxyzine will certainly render you extremely sleepy, this may only be used at night if for itch or allergy.
Inform your doctor of all medicine and vitamins that you are taking prior to using hydroxyzine.
American College of Obstetricians and Gynecologists advises hydroxyzine should not be used during the first three months of pregnancy.
Side Effects
Most patients easily tolerate hydroxyzine, but some of the side effects are:
- Sleepiness or drowsiness
- Dryness of mouth
- Dizziness
- Headache
- Blurred vision or
- Constipation
Serious but uncommon reactions:
- Uncommon heartbeat rhythm (QT prolongation)
- Severe hypersensitivity reaction (swelling of lip, face, throat, etc., breathlessness)
- Mental confusion or hallucinations in elderly patients
In case of breathlessness, fainting, or palpitations of the chest, contact the doctor immediately.
In the event of mouth dryness, suck an occasional puff of water or sugarless candy.
A 2020 safety review of Pharmacology Research & Perspectives warned against its use in low-risk patients with cardiac arrhythmia.
Drug Interactions
Hydroxyzine can interact with medicines that cause drowsiness or affect heart rhythm.
Examples:
- Sedative tranquilizing sleeping medications (zolpidem, benzodiazepines, barbiturates)
- Opioid pain relievers (oxycodone, morphine)
- Antidepressants (tricyclic antidepressants, SSRIs like fluoxetine)
- Antiarrhythmics (sotalol, amiodarone)
- Other antihistamines
The two together will cause sedation or risk of potentially life-threatening heart rhythm.
Always talk to your medical doctor before adding or stopping any medicine.
Overdose and Emergency Procedure
Excessive hydroxyzine may cause:
- Drowsiness or confusion in excess
- Seizures
- Irregular heartbeat
- Low blood pressure
- Difficulty breathing
In the event of overdose, seek emergency medical help right away(call 911 in the USA or your local emergency number).
Do not drive yourself to hospital.
Missed Dose and Storage
- Missed dose: Take if remembered other than when approaching time for next one. Do not take missed dose if so. Never double dose.
- Storage: Room temperature, a location which is kid- and pet-proof, away from heat, light, and water. Store in original container syrup and tablets.
Price and Availability
The cost of Hydroxyzine varies by brand, region, and insurance coverage.
- US generics $10–20 for 30 days on pharmacy discount plans.
- Brand name, i.e., Atarax or Vistaril, is more costly than generics.
- Is an inexpensive generic drug but has a variable price on the American market.
Hydroxyzine vs Other Antihistamines
Compared with second-generation antihistamines such as cetirizile or loratadine:
- Produces more sedation, beneficial in anxiety or insomnia.
- Causes relief of itch faster.
- To be administered more than once a day.
- For symptomatic relief of allergy with sedation.
How Long Do You Take Hydroxyzine?
Temporarily (weeks to weeks) for anxiety or insomnia, although frequently in chronic itch under close medical supervision.
Doctors will monitor patients at regular intervals continuing treatment to prevent side effects and to ensure the drug remains suitable.
Clinical Evidence and Research
Hydroxyzine has been approved by the U.S. Food and Drug Administration (FDA) for allergy and anxiety treatment for decades.
Its safety and efficacy as a medication for generalized anxiety disorder, hives (urticaria), and preoperative sedation when used as directed were confirmed through clinical trials.
Its safe use for centuries in both children and adults is strong evidence for its effectiveness when properly prescribed.
References
For current, accurate medical information and research support, refer to these reliable sources:
• Drugs.com – Overview and drug information about Hydroxyzine.
• MedlinePlus – Hydroxyzine patient brochure.
• WebMD – Safety of Hydroxyzine and oral administration.
• Cleveland Clinic – Hydroxyzine drug profile.
• DrugBank – Hydroxyzine pharmacology and interaction.
• NAMI – Hydroxyzine as a treatment for mental illness.
• Eur Neuropsychopharmacol, 2002 – Random control study validating the GAD anxiety in hydroxyzine treated patients.
• Drug Des Devel Ther, 2015 – Investigational research on CNS sedative effect of hydroxyzine.
• JAMA Psychiatry, 2021 – Clinical guide to hydroxyzine as short-term non-addictive treatment for anxiety.
• ACOG Committee Opinion, 2021– Advice against using hydroxyzine during the first trimester of pregnancy.
• Pharmacol Res Perspect, 2020 – QT-prolongation safety risk assessment. Also see Adverse Effect Monitoring section.

