What does the research show about hydroxyzine?

Hydroxyzine

A Cochrane review of five trials found hydroxyzine reduced generalized anxiety more than placebo over 4 to 12 weeks, with a high risk of bias. Evidence for itching and for sleep is limited and mixed. Sleepiness affected 28% against 14% on placebo in one trial. The label warns of QT prolongation and of added sedation with opioids and alcohol.

Add to Bio HackChecked 2026-11-13

Status: Prescription drug in the US, FDA-approved for symptomatic relief of anxiety and tension, for itching due to allergic conditions such as chronic hives and dermatitis, and as a sedative before and after general anesthesia. Use for sleep is off-label.
Also called: hydroxyzine hydrochloride, hydroxyzine pamoate, Atarax, Vistaril, sedating antihistamine, first-generation antihistamine
Taken for: anxiety, panic, itching, hives, sleep, insomnia, calming before surgery

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help2

ModerateShown to reduce generalized anxiety scores more than placebo over 4 to 12 weeks, by about 2.5 to 3.5 points on the Hamilton anxiety scale.
LimitedLimited evidence: hydroxyzine matched loratadine for clearing chronic hives in one comparison, and itch scores fell in a small dialysis trial with no placebo group.

Reported risks10

ModerateShown to cause sleepiness in 28% against 14% on placebo in a 4-week anxiety trial, appearing in the first week and fading with continued use.Very common
LimitedOne trial found side effects in 52% on hydroxyzine against 35% on placebo, with dry mouth in 14% against 5%.Very common
LimitedOne trial found hydroxyzine 50 mg increased lane weaving in an on-road driving test on day 1 and still on day 8 of daily use.How often is not known
LimitedThe label warns of QT prolongation and torsade de pointes, mostly in people with other risk factors, and lists a prolonged QT interval as a contraindication. It gives no rate.How often is not known
LimitedThe label states hydroxyzine potentiates central nervous system depressants such as narcotics and barbiturates, and that the effects of alcohol may be increased. It gives no rate.How often is not known
LimitedThe label warns that sedating drugs may cause confusion and over-sedation in older people. European regulators advise against hydroxyzine in older people. Neither gives a rate.How often is not known
LimitedThe label warns hydroxyzine may rarely cause acute generalized exanthematous pustulosis, a serious rash with fever and pustules. It gives no rate.How often is not known
LimitedThe label reports rare instances of tremor and convulsions, usually at doses considerably above the labeled range. It gives no rate.How often is not known
LimitedMixed results: the label lists early pregnancy as a contraindication on animal data, while one study of 53 exposed pregnancies found no rise in birth defects.How often is not known
LimitedLinked to more tic, anxiety and conduct disorder diagnoses by age 10 in children given repeat prescriptions before age 5, in one Canadian cohort.How often is not known

What people take it for, and what was found

Shown to help2

Moderate

Generalized anxiety

Shown to reduce generalized anxiety scores more than placebo over 4 to 12 weeks, by about 2.5 to 3.5 points on the Hamilton anxiety scale.

The numbers and sources

Effect: A Cochrane review of 5 studies found hydroxyzine more efficacious than placebo for generalized anxiety disorder (OR 0.30, 95% CI 0.15 to 0.58), and equivalent to chlordiazepoxide (OR 0.75, 95% CI 0.35 to 1.62) and buspirone (OR 0.76, 95% CI 0.40 to 1.42) [1]. In a 12-week trial of 50 mg a day, Hamilton anxiety scores fell by 12.16 points on hydroxyzine and 9.64 on placebo, with responder and remission rates also favoring hydroxyzine and no significant difference from the benzodiazepine bromazepam [2]. In a 4-week trial, scores improved by 10.75 points on hydroxyzine and 7.23 on placebo, and buspirone did not differ from placebo on that measure [3]. In a second 4-week trial, anxiety scores were lower than placebo from the first week [4].
Population: 884 participants in 5 studies [1]; 334 outpatients with generalized anxiety disorder [2]; 244 primary care patients, 70% women, mean age 41 [3]; 133 patients [4].
Sources: [1], [2], [3], [4]
Caveats: The Cochrane authors found a high risk of bias, few studies and small samples, and did not consider hydroxyzine a reliable first-line treatment on that basis [1]. The label states that use as an antianxiety agent beyond 4 months has not been assessed in systematic clinical studies [5].

Limited

Itching

Limited evidence: hydroxyzine matched loratadine for clearing chronic hives in one comparison, and itch scores fell in a small dialysis trial with no placebo group.

The numbers and sources

Effect: In a Cochrane review of antihistamines for chronic hives, complete suppression over the short term did not differ between hydroxyzine 25 mg and loratadine 10 mg (RR 1.00, 95% CI 0.32 to 3.10) [8]. In a crossover trial in people on dialysis, itch severity on a 10-point scale fell from 6.83 to 2.86 over 6 weeks on hydroxyzine 25 mg a day and from 7.1 to 2.17 on gabapentin, with no significant difference between the two [9]. A Cochrane review found no randomized trial of an oral antihistamine used alone for eczema [10].
Population: 73 studies of antihistamines with 9,759 participants, of which one comparison involved hydroxyzine [8]; 32 patients on dialysis [9].
Sources: [8], [9], [10]
Caveats: An approved use that rests on older evidence. Neither comparison here had a placebo arm for hydroxyzine, and the hives comparison had a wide confidence interval.

Mixed results1

Limited

Sleep

Small trials found mixed results for falling asleep, staying asleep and sleep quality on 25 to 100 mg of hydroxyzine at bedtime.

The numbers and sources

Effect: A systematic review found five studies, one open-label and four randomized, of hydroxyzine 25, 50 or 100 mg at bedtime. Results were mixed for sleep onset, sleep maintenance and sleep quality. Dry mouth was the most common adverse effect, and four of the five studies did not report safety outcomes [11].
Population: 207 adults in 5 studies [11].
Sources: [11]
Caveats: Not an approved use. Small, short studies with no pooled estimate and no long-term data.

Not shown to help2

Limited

Sudden anxiety and as-needed use

One trial found adding hydroxyzine to morphine did not significantly lower anxiety in 140 people with severe acute pain. No trial in panic attacks was located.

The numbers and sources

Effect: Among people with severe acute pain treated before reaching hospital, 91% given hydroxyzine with morphine reported no more severe anxiety against 78% given placebo with morphine, a difference that was not statistically significant. Pain relief at 15 minutes did not differ, at 51% against 52% [6]. The label states that clinical effects are usually noted within 15 to 30 minutes of an oral dose [5].
Population: 140 prehospital patients with acute pain scored 6 or more out of 10 [6].
Sources: [6], [5]
Caveats: One trial in an emergency setting, with hydroxyzine added to an opioid. It does not test a single dose taken for panic or everyday anxiety, and no such trial was located.

Limited

Calming before surgery

One trial found hydroxyzine did not lower anxiety before surgery against placebo in 165 children aged 2 to 16.

The numbers and sources

Effect: Anxiety scores at the time of anesthesia induction did not differ between hydroxyzine and placebo (39.2 against 37.0 on a preoperative anxiety scale, P = 0.788), with or without clowns as a distraction [7]. Sedation before and after general anesthesia is a labeled use, and the label states that hydroxyzine may potentiate meperidine and barbiturates given with it [5].
Population: 165 children aged 2 to 16 having outpatient surgery [7].
Sources: [7], [5]
Caveats: One trial in children, all accompanied by their parents. No recent placebo-controlled trial in adults was located.

Doses studied

The label gives 50 to 100 mg four times a day for anxiety in adults, 25 mg three or four times a day for itching, and 50 to 100 mg as a sedative before or after general anesthesia [5]. The anxiety trials used 50 mg a day, in one trial split as 12.5 mg in the morning, 12.5 mg at midday and 25 mg in the evening [2][3][4]. The sleep studies used 25, 50 or 100 mg at bedtime [11], the dialysis itch trial 25 mg a day [9], and the driving study 50 mg once a day [12].

In 2015 the European Medicines Agency set a ceiling of 100 mg a day for adults and 50 mg a day for older people in Europe because of heart rhythm risk [13].

Risks

Reported risks9

ModerateVery common

Drowsiness

Shown to cause sleepiness in 28% against 14% on placebo in a 4-week anxiety trial, appearing in the first week and fading with continued use.

The numbers and sources

How common: Very common: more than 1 in 10 people.
Effect: At 50 mg a day, sleepiness was reported by 28% on hydroxyzine and 14% on placebo. It appeared in the first week and progressively disappeared later in treatment [4]. In the Cochrane review, sleepiness or drowsiness was more frequent on hydroxyzine than on benzodiazepines or buspirone, without reaching significance (OR 1.74, 95% CI 0.86 to 3.53) [1]. The label states that drowsiness is usually transitory and may disappear within a few days or on a lower dose [5].
Population: 133 patients with generalized anxiety disorder [4]; 884 participants in 5 studies [1].
Sources: [4], [1], [5]
Caveats: The rate comes from one trial at 50 mg a day, below the label's dose range for anxiety.

LimitedVery common

Dry mouth and other common side effects

One trial found side effects in 52% on hydroxyzine against 35% on placebo, with dry mouth in 14% against 5%.

The numbers and sources

How common: Very common: more than 1 in 10 people.
Effect: Over 4 weeks at 50 mg a day, any side effect was reported by 52% on hydroxyzine and 35% on placebo: dry mouth 14% vs 5%, weight gain 12% vs 10%, loss of concentration 9% vs 8% and insomnia 9% vs 6% [4]. The label lists dry mouth as an anticholinergic effect and headache and hallucination among postmarketing reports [5].
Population: 133 patients with generalized anxiety disorder [4].
Sources: [4], [5]
Caveats: One trial of 4 weeks. The label gives no rates.

LimitedHow often is not known

Driving impairment

One trial found hydroxyzine 50 mg increased lane weaving in an on-road driving test on day 1 and still on day 8 of daily use.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: In a placebo-controlled crossover study with an on-road highway driving test, hydroxyzine 50 mg once a day significantly increased the standard deviation of lateral position on days 1 and 8. The authors described the impairment as severe after a single dose and only partly reduced with repeated dosing [12]. The label states that drowsiness may occur and cautions against driving or operating dangerous machinery [5].
Population: 22 healthy volunteers, 11 women and 11 men [12].
Sources: [12], [5]
Caveats: One small study in healthy volunteers, in which hydroxyzine was the active control for another antihistamine.

LimitedHow often is not known

QT prolongation and torsade de pointes

The label warns of QT prolongation and torsade de pointes, mostly in people with other risk factors, and lists a prolonged QT interval as a contraindication. It gives no rate.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The label reports postmarketing cases of QT prolongation and torsade de pointes, most in people with existing heart disease, electrolyte imbalances or use of other arrhythmia-causing drugs. It names other QT-prolonging drugs as a concern: some antiarrhythmics, antipsychotics such as quetiapine and ziprasidone, the antidepressants citalopram and fluoxetine, the antibiotics azithromycin, erythromycin, clarithromycin, gatifloxacin and moxifloxacin, and methadone, ondansetron and others [5]. A review of the manufacturer's safety database from 1955 to 2016 found 59 reports potentially linked to hydroxyzine. Apart from intentional overdose, every case had at least one other risk factor, and laboratory studies showed concentration-dependent inhibition of cardiac ion channels [14]. The European Medicines Agency confirmed the risk in 2015, concluded that events are most likely in people with risk factors, and restricted use and dose [13].
Population: 59 pharmacovigilance reports over about 60 years [14]; postmarketing reports summarized by regulators [5][13].
Sources: [5], [14], [13]
Caveats: Spontaneous reports with no denominator. The database review was conducted by the manufacturer [14].

LimitedHow often is not known

Opioids, alcohol and other sedating drugs

The label states hydroxyzine potentiates central nervous system depressants such as narcotics and barbiturates, and that the effects of alcohol may be increased. It gives no rate.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The label states that the potentiating action of hydroxyzine must be considered when it is used with central nervous system depressants such as narcotics, non-narcotic analgesics and barbiturates, that it may potentiate meperidine and barbiturates used around anesthesia, and that the effects of alcohol may be increased [5].
Population: Labeling statement [5].
Sources: [5]
Caveats: No study data are given in the label.

LimitedHow often is not known

Older adults

The label warns that sedating drugs may cause confusion and over-sedation in older people. European regulators advise against hydroxyzine in older people. Neither gives a rate.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The label states that sedating drugs may cause confusion and over-sedation in the elderly, and that it has not been determined whether trials included enough people aged 65 and over to detect a difference in response [5]. The European Medicines Agency stated in 2015 that older people are advised not to use hydroxyzine, with a ceiling of 50 mg a day if they do [13].
Population: Labeling and regulatory statements [5][13].
Sources: [5], [13]
Caveats: No trial data in older adults are given.

LimitedHow often is not known

Serious skin reaction

The label warns hydroxyzine may rarely cause acute generalized exanthematous pustulosis, a serious rash with fever and pustules. It gives no rate.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The label describes acute generalized exanthematous pustulosis and fixed drug eruptions in postmarketing reports, and warns of cross-sensitivity with the related antihistamines cetirizine and levocetirizine [5].
Population: Postmarketing reports summarized in labeling [5].
Sources: [5]
Caveats: The label says "rarely" without a frequency, so no band can be set.

LimitedHow often is not known

Tremor and seizures at high doses

The label reports rare instances of tremor and convulsions, usually at doses considerably above the labeled range. It gives no rate.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The label lists involuntary motor activity, including rare instances of tremor and convulsions, usually with doses considerably higher than those on the label. In overdose it lists hypersedation as the most common sign, along with convulsions, stupor, nausea and vomiting [5].
Population: Labeling statement [5].
Sources: [5]
Caveats: No denominator is given.

LimitedStudied in childrenHow often is not known

Repeated use in young children

Linked to more tic, anxiety and conduct disorder diagnoses by age 10 in children given repeat prescriptions before age 5, in one Canadian cohort.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: Compared with a single prescription, repeat prescriptions of hydroxyzine before age 5 were associated with higher odds of a tic disorder (OR 1.55, 95% CI 1.23 to 1.96), anxiety (OR 1.34, 95% CI 1.05 to 1.70) and disturbance of conduct (OR 1.34, 95% CI 1.08 to 1.66) by age 10. ADHD showed a rise that was not significant [16].
Population: Children under 5 in British Columbia, Canada, where 1.1% were prescribed hydroxyzine [16].
Sources: [16]
Caveats: Observational, with no unexposed comparison in the main result. The conditions that lead to repeat prescriptions, such as eczema, may explain part of the association, and the authors called for controlled studies.

Mixed results1

LimitedHow often is not known

Pregnancy

Mixed results: the label lists early pregnancy as a contraindication on animal data, while one study of 53 exposed pregnancies found no rise in birth defects.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: The label states that hydroxyzine caused fetal abnormalities in rats and mice at doses substantially above the human range, that human data are inadequate, and that the drug is contraindicated in early pregnancy [5]. In a prospective controlled study, 53 women exposed to hydroxyzine during organ formation had rates of major and minor anomalies, live birth, miscarriage, birth weight and neonatal distress that did not differ from controls [15].
Population: 120 women exposed to hydroxyzine or cetirizine in pregnancy, 53 of them to hydroxyzine during organogenesis [15].
Sources: [5], [15]
Caveats: The human study is too small to detect uncommon birth defects.

Checked, no increase found1

Limited

Rebound and withdrawal after stopping

One trial found no rebound of anxiety and no withdrawal symptoms a week after abruptly stopping hydroxyzine 50 mg a day taken for 4 weeks.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: In a placebo-controlled trial, the advantage of hydroxyzine over placebo on anxiety scores persisted at an evaluation one week after abrupt discontinuation, with no rebound of anxiety or withdrawal symptoms reported [4].
Population: 133 patients with generalized anxiety disorder treated for 4 weeks [4].
Sources: [4]
Caveats: One trial of 4 weeks at 50 mg a day. No study of stopping after longer use or higher doses was located, and no study of misuse or dependence was located.

Claims tested and not found

That stopping hydroxyzine brings rebound anxiety. In a 4-week placebo-controlled trial of 50 mg a day, no rebound of anxiety or withdrawal symptoms appeared in the week after abrupt discontinuation [4].
That hydroxyzine calms children before surgery. In 165 children aged 2 to 16, anxiety at anesthesia induction did not differ between hydroxyzine and placebo [7].
That adding hydroxyzine to morphine eases pain by easing anxiety. In 140 people with severe acute pain, pain relief at 15 minutes was 51% with hydroxyzine and 52% with placebo, and anxiety did not differ significantly [6].

Sources

Guaiana G, Barbui C, Cipriani A. Hydroxyzine for generalised anxiety disorder. Cochrane Database of Systematic Reviews. 2010. https://doi.org/10.1002/14651858.CD006815.pub2
Llorca PM, Spadone C, Sol O, et al. Efficacy and safety of hydroxyzine in the treatment of generalized anxiety disorder: a 3-month double-blind study. The Journal of Clinical Psychiatry. 2002. https://doi.org/10.4088/jcp.v63n1112
Lader M, Scotto JC. A multicentre double-blind comparison of hydroxyzine, buspirone and placebo in patients with generalized anxiety disorder. Psychopharmacology. 1998. https://doi.org/10.1007/s002130050731
Ferreri M, Hantouche EG, Billardon M. Value of hydroxyzine in generalized anxiety disorder: controlled double-blind study versus placebo. L'Encephale. 1994. https://pubmed.ncbi.nlm.nih.gov/7875114/
U.S. Food and Drug Administration. Hydroxyzine hydrochloride tablets, prescribing information (Marlex Pharmaceuticals). 2026. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=31a907e6-7fae-0682-e063-6294a90a24a5
Houze-Cerfon CH, Balen F, Houze-Cerfon V, et al. Hydroxyzine for lowering patient's anxiety during prehospital morphine analgesia: A prospective randomized double blind study. The American Journal of Emergency Medicine. 2021. https://doi.org/10.1016/j.ajem.2021.09.061
Aleo E, Picado AL, Abancens BJ, et al. Evaluation of the Effect of Hydroxyzine on Preoperative Anxiety and Anesthetic Adequacy in Children: Double Blind Randomized Clinical Trial. BioMed Research International. 2021. https://doi.org/10.1155/2021/7394042
Sharma M, Bennett C, Cohen SN, Carter B. H1-antihistamines for chronic spontaneous urticaria. Cochrane Database of Systematic Reviews. 2014. https://doi.org/10.1002/14651858.CD006137.pub2
Mohammadi Kebar S, Sharghi A, Ghorghani M, Hoseininia S. Comparison of gabapentin and hydroxyzine in the treatment of pruritus in patients on dialysis. Clinical and Experimental Dermatology. 2020. https://doi.org/10.1111/ced.14270
Apfelbacher CJ, van Zuuren EJ, Fedorowicz Z, et al. Oral H1 antihistamines as monotherapy for eczema. Cochrane Database of Systematic Reviews. 2013. https://doi.org/10.1002/14651858.CD007770.pub2
Burgazli CR, Rana KB, Brown JN, Tillman F. Efficacy and safety of hydroxyzine for sleep in adults: Systematic review. Human Psychopharmacology: Clinical and Experimental. 2023. https://doi.org/10.1002/hup.2864
Conen S, Theunissen EL, Van Oers AC, et al. Acute and subchronic effects of bilastine (20 and 40 mg) and hydroxyzine (50 mg) on actual driving performance in healthy volunteers. Journal of Psychopharmacology. 2011. https://doi.org/10.1177/0269881110382467
European Medicines Agency. New restrictions to minimise the risks of effects on heart rhythm with hydroxyzine-containing medicines. 2015. https://www.ema.europa.eu/en/news/new-restrictions-minimise-risks-effects-heart-rhythm-hydroxyzine-containing-medicines
Schlit AF, Delaunois A, Colomar A, et al. Risk of QT prolongation and torsade de pointes associated with exposure to hydroxyzine: re-evaluation of an established drug. Pharmacology Research & Perspectives. 2017. https://doi.org/10.1002/prp2.309
Einarson A, Bailey B, Jung G, et al. Prospective controlled study of hydroxyzine and cetirizine in pregnancy. Annals of Allergy, Asthma & Immunology. 1997. https://doi.org/10.1016/S1081-1206(10)63385-6
Gober HJ, Li KH, Yan K, et al. Hydroxyzine Use in Preschool Children and Its Effect on Neurodevelopment: A Population-Based Longitudinal Study. Frontiers in Psychiatry. 2022. https://doi.org/10.3389/fpsyt.2021.721875

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