Hydroxyzine: Independent Evidence on Anxiety, QT Risk, Side Effects & Withdrawal

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Key takeaways
  • Hydroxyzine (Atarax, Ucerax, Vistaril) is an old, sedating antihistamine. In the UK it is licensed "to assist in the management of anxiety in adults" and for itching (UK SmPC, MHRA 2015). In the US it is approved for "anxiety and tension associated with psychoneurosis" (FDA label).
  • It probably reduces generalised anxiety more than placebo, but the evidence is weak. A Cochrane review found only five trials (884 people) with a high risk of bias, two of them sponsored by the manufacturer, and concluded it cannot be recommended "as a reliable first-line treatment" (Guaiana et al., Cochrane 2010).
  • In 2015 European regulators confirmed a small risk of dangerous heart-rhythm changes (QT prolongation and torsade de pointes). The UK maximum dose was cut to 100 mg a day for adults and 50 mg a day for older people, "if use cannot be avoided" (MHRA Drug Safety Update, April 2015, EMA). The US label still lists up to 100 mg four times a day for anxiety.
  • Older adults should avoid it. The MHRA says to avoid it in the elderly, and the 2023 AGS Beers Criteria list hydroxyzine as a "highly anticholinergic" first-generation antihistamine to avoid (strong recommendation) (AGS Beers Criteria 2023).
  • NICE says sedating antihistamines "should not be prescribed" for panic disorder, and does not list hydroxyzine among its GAD treatments (NICE CG113).
  • Its main practical advantages over benzodiazepines are that it is not a controlled drug and, in trials, withdrawal symptoms were no more common than on placebo (Cochrane full text). Drowsiness, dry mouth and impaired driving are common. It must not be used in pregnancy or breastfeeding (UK SmPC).
  • Evidence grade: Weak for short-term generalised anxiety · Insufficient for long-term use and panic · Risk for QT prolongation and anticholinergic harm in older adults

Independent evidence review · Prescription medicine

Hydroxyzine is a 1950s antihistamine that calms partly by making you drowsy. It is less addictive than a benzodiazepine, but it is not a first-choice anxiety treatment: the trial evidence is small and dated, and it can disturb heart rhythm and cloud thinking, especially in older people. The best independent review, from Cochrane, found it beat placebo in generalised anxiety disorder. But the review rested on five trials with a high risk of bias, two of them paid for by the maker. Since 2015, UK and EU regulators have limited the dose and told prescribers to avoid it in people with heart-rhythm risks and in the elderly (Cochrane 2010, MHRA 2015).

Best evidence for short-term relief of generalised anxiety (weak); itching from urticaria and dermatitis
Main risks drowsiness, dry mouth, impaired driving, QT prolongation and abnormal heart rhythms, confusion and falls in older people
Key rule UK maximum 100 mg a day (50 mg in older people). Never combine with alcohol or other QT-prolonging medicines. Not in pregnancy.
Safety first
Hydroxyzine is a prescription-only medicine. Do not start, stop or change your dose without your prescriber. It causes drowsiness and can impair your judgement and co-ordination, so do not drive or operate machinery until you know how it affects you. Do not drink alcohol with it, and do not combine it with opioids, benzodiazepines, sleeping tablets or other sedatives unless your prescriber has planned this (UK SmPC, FDA label). Tell your prescriber about every other medicine you take, because many common ones (including citalopram, escitalopram, some antibiotics and methadone) must not be combined with it. Stop taking it and get urgent medical help (999 in the UK, 911 in the US) if you have palpitations, a fast or irregular heartbeat, fainting or a seizure (SmPC 4.4). If someone has taken too much, call 999 or go to A&E. If anxiety is making you feel hopeless or think about harming yourself, seek urgent help: call 999 or 111 in the UK (or 988 in the US), or Samaritans on 116 123.

Table of contents

Evidence summary

Claim Evidence Source Funding / conflict Strength
More effective than placebo for generalised anxiety disorder (GAD) 5 randomised trials, 884 people. Odds ratio 0.30 (95% CI 0.15 to 0.58) in favour of hydroxyzine. High risk of bias; small number of trials. Guaiana et al., Cochrane 2010 Cochrane review; University of Verona internal support only; no conflicts known. 2 of 5 included trials manufacturer-sponsored. Weak
As effective as benzodiazepines or buspirone No significant difference against chlordiazepoxide (OR 0.75, 95% CI 0.35 to 1.62) or buspirone (OR 0.76, 95% CI 0.40 to 1.42). "Not possible" to draw firm conclusions because of low study quality. Cochrane 2010 full text As above Insufficient
Reduces anxiety scores over 3 months 334 outpatients: HAM-A fell by 12.16 points on hydroxyzine 50 mg/day against 9.64 on placebo (p = 0.019). No significant difference from bromazepam. Llorca et al., J Clin Psychiatry 2002 French multicentre trial; funding not shown in the abstract record (Cochrane says two included trials were manufacturer-sponsored) Moderate (single trial)
Reduces anxiety over 4 weeks in primary care 244 patients: HAM-A improved 10.75 points on hydroxyzine against 7.23 on placebo; buspirone not significantly better than placebo on the primary measure. Lader and Scotto, Psychopharmacology 1998 UK/France multicentre; funding not shown in the abstract record Weak
Works for panic disorder NICE: sedating antihistamines "should not be prescribed" for panic disorder. NICE CG113, 1.3.21 UK public body Insufficient
Effective long term (more than 4 months) "Has not been assessed by systematic clinical studies." FDA label US regulator Insufficient
Blocks anxiety from a lab stressor after a single dose In 12 healthy volunteers, 25 mg did not reduce CO2-induced anxiety compared with placebo. Papadopoulos et al. 2010 UK academic; funding not shown in the abstract record Weak (against)
Causes QT prolongation and torsade de pointes Confirmed by an EU-wide review of clinical and post-marketing data; risk small and mostly in people with risk factors. EMA 2015, MHRA 2015 Regulators Risk
Harmful in older adults Highly anticholinergic, with reduced clearance in old age; risks of confusion, falls and delirium. Recommendation: avoid (moderate-quality evidence, strong recommendation). AGS Beers Criteria 2023 US professional society; "no sponsor" Risk

Independent evidence and credibility scorecard

Source Who funds it Country Independence tier (1–4) Credibility (A–D) Why it would tell the truth / residual bias
Cochrane review (Guaiana 2010) University of Verona internal support; "no sources of support supplied" externally; declarations "none known" Italy / Canada 1 A– No money from hydroxyzine makers. Residual bias: it can only pool the trials that exist, which are few and at high risk of bias; its last search was in March 2010.
MHRA Drug Safety Update 2015 UK government regulator UK 1 A Legal duty to protect patients; based on a Europe-wide review. Residual bias: conservative by design, preferring restriction when uncertain.
EMA PRAC / CMDh referral EU regulatory network EU 2 A– Public assessment of all available data. Residual bias: the EMA receives industry fees, although this review restricted the drug.
AGS Beers Criteria 2023 American Geriatrics Society; "no sponsor" US 1–2 A– A panel focused on harms in older adults. Residual bias: applies a class-wide judgement to all first-generation antihistamines.
NICE CG113 UK public body funded mainly by government UK 1–2 A– Evidence-led and cost-conscious. Residual bias: the panic recommendation dates from 2004 and has not been re-reviewed.
Llorca 2002 and Lader 1998 trials Not shown in the abstract records; Cochrane reports that two of the five included trials, among the most recent, were sponsored by the manufacturer France / UK 3–4 C+ Reasonably sized, double-blind, placebo-controlled. Residual bias: likely sponsor involvement; Cochrane rated the overall risk of bias as high.
UK SmPC and US label Written by licence holders, approved by regulators UK / US 2 B Legal documents that must list known risks. Residual bias: the US generic label still carries 1950s-era dosing and efficacy wording.

What hydroxyzine is

Hydroxyzine is a first-generation antihistamine of the piperazine family, with antimuscarinic (anticholinergic) and sedative properties. Despite being an antihistamine, it is classified with anxiolytics (ATC code N05BB01), and it is chemically unrelated to benzodiazepines (UK SmPC).

  • Brand names: Atarax and Ucerax in the UK (MHRA). Atarax (hydroxyzine hydrochloride) and Vistaril (the pamoate salt) in the US, both now discontinued as brands (Drugs@FDA). When we searched the UK medicines compendium in September 2026, it listed only generic hydroxyzine tablets from Morningside Healthcare and Ipca Laboratories (emc).
  • Originator: UCB (Union Chimique Belge) of Belgium. UCB's own history says its pharmaceutical research centre, founded in 1952, discovered Atarax, "one of the world's first tranquillisers". UCB granted the US licence to Pfizer (UCB company history, in German). An early pharmacology paper calls the compound "UCB 492" (reference list, Cochrane 2010).
  • US approval: Atarax tablets were approved on 12 April 1956 under NDA 010392 (Pfizer), and Vistaril on 18 September 1957 (NDA 011111, Pfizer) (Drugs@FDA Atarax, Drugs@FDA Vistaril).
  • Generic status: off-patent. The openFDA Drugs@FDA database lists 110 application records containing hydroxyzine hydrochloride (openFDA).
  • Prescription status: prescription-only in the UK (SmPC) and in the US. It is not a controlled drug.

How it works

Hydroxyzine blocks histamine H1 receptors. Because it is a first-generation antihistamine, it crosses easily into the brain, which causes sedation and anticholinergic effects. It also has some affinity for serotonin (5-HT), alpha-adrenergic and muscarinic receptors (UK SmPC). Its calming effect is thought to come from suppressing activity in "certain key regions of the subcortical area" of the brain, but the exact mechanism in anxiety is not established (FDA label).

In practice, much of its anti-anxiety effect overlaps with sedation. The Cochrane review found more sleepiness on hydroxyzine than on active comparators (OR 1.74, 95% CI 0.86 to 3.53), although that difference was not statistically significant (Cochrane 2010).

  • Onset: sedation usually begins 15 to 30 minutes after a dose and lasts 4 to 6 hours (SmPC).
  • Half-life: about 14 to 20 hours in adults. In healthy older people it averaged 29.3 hours (range 20.2 to 53.3), and in liver impairment 36.6 hours. This is why the effects can build up and why older people get a lower maximum dose (SmPC 5.2).
  • Active metabolite: hydroxyzine is broken down in the liver into cetirizine, the familiar non-drowsy hay fever antihistamine, which is cleared by the kidneys (SmPC).

What it is prescribed for

Licensed uses

  • UK: "to assist in the management of anxiety in adults", and itching (pruritus) from acute and chronic urticaria and from atopic and contact dermatitis in adults and children (UK SmPC).
  • US: "symptomatic relief of anxiety and tension associated with psychoneurosis" and anxiety linked to physical illness; itching from allergic conditions; and as a sedative before and after general anaesthesia (FDA label).
  • Elsewhere in Europe: approved uses vary by country and may also include premedication before surgery and sleep disorders (EMA). It is not licensed for insomnia in the UK.

Where guidelines place it

  • Generalised anxiety disorder: NICE CG113 recommends psychological therapy or an SSRI, with sertraline first, then another SSRI or an SNRI, then pregabalin. Hydroxyzine is not among its recommended options (NICE CG113).
  • Panic disorder: "Sedating antihistamines or antipsychotics should not be prescribed for the treatment of panic disorder" (NICE CG113, 1.3.21).
  • Cochrane: "not possible to recommend hydroxyzine as a reliable first-line treatment in GAD" (Guaiana 2010).
  • Regulators: use "the lowest effective dose for as short a time as possible" (MHRA).

In practice, hydroxyzine tends to be used as a short-term, non-benzodiazepine option: for example while waiting for an SSRI to start working, or for people who cannot take benzodiazepines. That is a reasonable niche, but it rests more on its safety profile relative to benzodiazepines than on strong evidence of benefit.

What works and what does not

Use Verdict Why
Short-term generalised anxiety disorder Mixed Beats placebo in a Cochrane meta-analysis, but with five trials at high risk of bias, two of them industry-sponsored (Cochrane 2010)
Itching from urticaria or dermatitis Works Licensed UK and US use (SmPC); not reviewed in depth here
Long-term anxiety treatment (more than 4 months) Insufficient Not assessed in systematic clinical studies (FDA label)
Panic disorder Insufficient NICE advises against sedating antihistamines (NICE)
Compared with SSRIs or SNRIs Insufficient No head-to-head trials exist (Cochrane 2010)
Single dose for acute stress Insufficient No effect on lab-induced anxiety in one small study (Papadopoulos 2010)

Benefits by claim

Generalised anxiety disorder: the Cochrane review

The Cochrane review searched to March 2010 and found 39 studies, of which five randomised trials with 884 participants met its criteria (Guaiana, Barbui and Cipriani, Cochrane 2010):

  • Against placebo: hydroxyzine was more effective (OR 0.30, 95% CI 0.15 to 0.58). Dropout rates were similar (OR 1.00, 95% CI 0.63 to 1.58), and dropouts due to side effects did not differ significantly (OR 1.37, 95% CI 0.50 to 3.76; 3 trials, 505 people).
  • Against benzodiazepines and buspirone: no significant difference in efficacy (against chlordiazepoxide, OR 0.75, 95% CI 0.35 to 1.62; against buspirone, OR 0.76, 95% CI 0.40 to 1.42).
  • Against antidepressants: no trials, so no comparison was possible.
  • Quality: "high risk of bias", two very old trials with vague diagnostic criteria, possible selective reporting, and two trials sponsored by the manufacturer. The authors noted that "some of the most recent studies were also sponsored by the pharmaceutical company manufacturing hydroxyzine, which can be another source of bias" (full text).

The two largest trials

Llorca et al. 2002 (France): 334 outpatients with DSM-IV GAD were randomised to hydroxyzine 50 mg a day, bromazepam 6 mg a day, or placebo for 12 weeks. On the main anxiety scale (HAM-A), scores fell by 12.16 points on hydroxyzine and 9.64 on placebo, a difference of about 2.5 points (p = 0.019). Response and remission rates also favoured hydroxyzine. Hydroxyzine did not differ significantly from bromazepam, and drowsiness was more frequent with bromazepam (Llorca 2002).

Lader and Scotto 1998 (UK and France): 244 primary-care patients took hydroxyzine (12.5 mg morning and midday, 25 mg evening), buspirone or placebo for 4 weeks. HAM-A improved 10.75 points on hydroxyzine against 7.23 on placebo, about 3.5 points. Only hydroxyzine separated from placebo on the main measure (Lader 1998).

Is the effect clinically meaningful?

A 2.5 to 3.5 point advantage on the 56-point HAM-A scale is similar in size to the average drug–placebo differences reported for SSRIs and SNRIs in GAD trials. For example, a large network meta-analysis estimated about 2.5 points for escitalopram and 3.1 for duloxetine (Slee et al., Lancet 2019). These figures come from different trials, so they cannot be compared directly. An older pooled analysis of 21 GAD trials gave antihistamines (meaning hydroxyzine) a mean effect size of 0.45, against 0.36 for SSRIs, but it pooled only a handful of hydroxyzine trials (Hidalgo et al. 2007).

Two cautions stop us from rating this higher. First, placebo response was large: patients on placebo improved by 7 to 10 points. Second, a sedating drug can lower anxiety-scale scores partly by improving sleep and reducing tension, which are items on the scale, without treating the underlying worry. Neither point means the benefit is unreal. Both mean the evidence is thinner than the headline numbers suggest.

Risks and all side effects

Common side effects

The most common effect is central nervous system depression, "from slight drowsiness to deep sleep", including tiredness, dizziness and poor co-ordination. Sedation may lessen after a few days. Other common effects are headache, psychomotor impairment and antimuscarinic effects such as dry mouth, blurred vision, constipation and difficulty passing urine (UK SmPC). The US label describes side effects as "usually mild and transitory", with dry mouth and drowsiness the main ones (FDA label).

Serious and less common effects

Effect What the sources say Source
QT prolongation and torsade de pointes Hydroxyzine can block hERG and other cardiac channels. An EU review confirmed "a small risk" of QT prolongation and torsade de pointes, which can lead to cardiac arrest. Most cases had other risk factors, electrolyte problems or interacting medicines. EMA, MHRA
Excess sedation with alcohol, opioids or other sedatives Enhances response to alcohol, benzodiazepines, opioids, hypnotics and other CNS depressants; the US label tells prescribers to reduce the doses of these. SmPC 4.5, FDA label
Confusion, delirium and falls in older adults "Highly anticholinergic". Cumulative anticholinergic exposure is linked to falls, delirium and dementia. Beers: avoid. MHRA: avoid in the elderly. Beers 2023, MHRA
Serious skin reactions Acute generalised exanthematous pustulosis (AGEP), fixed drug eruptions; very rarely Stevens-Johnson syndrome, toxic epidermal necrolysis and erythema multiforme SmPC, FDA label
Seizures and involuntary movements Tremor and convulsions, usually at doses "considerably higher than those recommended"; dyskinesia may follow stopping after prolonged use SmPC
Allergic reactions Hypersensitivity, anaphylaxis and angioedema (frequency not known) SmPC
Paradoxical agitation Agitation, confusion, hallucinations, nightmares, increased anxiety; paradoxical stimulation "especially at high doses and in children and the elderly" SmPC
Anticholinergic effects Dry mouth, blurred vision, constipation, urinary retention; caution in glaucoma and enlarged prostate SmPC
Blood and liver Blood disorders including agranulocytosis and thrombocytopenia; liver dysfunction (frequency not known) SmPC
Other effects Low blood pressure, palpitations, fast heart rate, bronchospasm, nausea, weight gain, tinnitus, impotence, priapism SmPC

The 2015 QT review

In 2015, the EMA's Pharmacovigilance Risk Assessment Committee (PRAC) reviewed hydroxyzine after concerns about heart-rhythm problems. It "confirmed a previously known risk" of QT prolongation and torsade de pointes, found that the risk "did not differ between indications", and concluded that events were most likely in people with risk factors. EU member states' co-ordination group (CMDh) agreed the measures by consensus (EMA). The MHRA's April 2015 Drug Safety Update told UK prescribers (MHRA):

  • not to prescribe it to people with a prolonged QT interval or risk factors for it;
  • to avoid it in the elderly;
  • to consider the risk before prescribing to people taking medicines that lower heart rate or potassium;
  • the maximum daily dose is now 100 mg for adults, 50 mg for the elderly "if use cannot be avoided", and 2 mg per kg for children up to 40 kg;
  • to prescribe the lowest effective dose for as short a time as possible.

The MHRA listed these risk factors: other QT-prolonging medicines, cardiovascular disease, a family history of sudden cardiac death, significant electrolyte imbalance (low potassium or magnesium), and significant bradycardia.

A UK/US gap: the current US label still gives an anxiety dose of "50 to 100 mg q.i.d." (four times a day), which is up to 400 mg a day. It says to use hydroxyzine "with caution" in people with QT risk factors rather than contraindicating it. It does list a prolonged QT interval as a contraindication (FDA label). US readers should know that European regulators judged such doses unsafe.

Dependence and withdrawal

Unlike benzodiazepines, hydroxyzine is not a controlled drug. In the Cochrane review, withdrawal symptoms were not more common than on placebo (OR 1.43, 95% CI 0.62 to 3.30; one trial, 218 people), and older studies suggested no dependence or abuse potential (Cochrane 2010). The evidence on long-term use is limited, and dyskinesia (abnormal movements) "may follow termination of prolonged antihistamine therapy" (SmPC).

Overdose

Overdose can cause deep sedation, or agitation, hallucinations and seizures. Other effects include a fast heart rate, QRS widening and QT prolongation, heart block, coma and cardiorespiratory collapse. There is no specific antidote. People are usually observed for 6 hours with ECG monitoring (SmPC 4.9, FDA label).

All interactions

Medicine or substance What can happen Source
QT-prolonging medicines: class IA and III antiarrhythmics (quinidine, disopyramide, amiodarone, sotalol), some antipsychotics (haloperidol), some antidepressants (citalopram, escitalopram), some antibiotics (erythromycin, levofloxacin, moxifloxacin), mefloquine, pentamidine, prucalopride, toremifene, vandetanib, methadone Increased risk of dangerous heart rhythms. Contraindicated in the UK. SmPC 4.3, 4.5
Alcohol Increased sedation and impairment; avoid SmPC, FDA label
Opioids, benzodiazepines, hypnotics, barbiturates, antipsychotics, antidepressants, antiepileptics, muscle relaxants, other antihistamines, anaesthetics Additive central nervous system depression; doses may need adjusting SmPC, FDA label
Medicines that slow the heart or lower potassium (for example beta blockers, some diuretics) Use with caution because of QT risk MHRA, SmPC
Anticholinergic medicines (atropine, tricyclic antidepressants, MAOIs, bladder antimuscarinics) Additive anticholinergic effects; Beers advises counting total anticholinergic burden SmPC, Beers 2023
Strong CYP3A4/5 inhibitors; cimetidine May raise hydroxyzine levels SmPC
CYP2D6 substrates Hydroxyzine inhibits CYP2D6 and may raise their levels SmPC
Adrenaline Hydroxyzine can block and reverse adrenaline's blood-pressure effect; epinephrine should not be used to treat hypotension in overdose SmPC, FDA label
Anticholinesterase drugs; betahistine Hydroxyzine may oppose their effects SmPC
Ototoxic drugs (for example aminoglycoside antibiotics) Sedating antihistamines may mask warning signs of ear damage SmPC
Allergy skin tests; methacholine test Stop at least one week before skin testing and 96 hours before a methacholine test SmPC
Cetirizine or levocetirizine allergy Contraindicated (cetirizine is hydroxyzine's metabolite) SmPC, FDA label

Who should avoid hydroxyzine

Must not take it (UK contraindications)

  • Allergy to hydroxyzine, cetirizine, other piperazine derivatives, aminophylline or ethylenediamine
  • A known congenital or acquired prolonged QT interval, or a known QT risk factor: cardiovascular disease, significant low potassium or magnesium, family history of sudden cardiac death, significant bradycardia, or taking QT-prolonging drugs
  • Asthma with a previous serious antihistamine-induced breathing reaction
  • Porphyria
  • Pregnancy and breastfeeding

(UK SmPC 4.3)

Use with caution

Epilepsy and other seizure disorders, myasthenia gravis, dementia, glaucoma, urinary retention or enlarged prostate, slow gut movement, stenosing peptic ulcer, breathing problems such as emphysema or chronic bronchitis, overactive thyroid, heart disease and high blood pressure (SmPC 4.4).

Older adults

Both UK regulators and US geriatric experts say to avoid it. The MHRA says to "avoid use in the elderly", because they are more susceptible to side effects, and to use no more than 50 mg a day if it cannot be avoided (MHRA). The 2023 Beers Criteria list hydroxyzine among first-generation antihistamines to avoid. They cite its high anticholinergic activity, reduced clearance in older age, and risks of confusion, constipation and anticholinergic toxicity. Cumulative anticholinergic exposure is "associated with an increased risk of falls, delirium, and dementia, even in younger adults". Quality of evidence: moderate; strength of recommendation: strong. Hydroxyzine also appears on the Beers list of drugs with strong anticholinergic properties (AGS Beers Criteria 2023). In older volunteers the half-life averaged 29.3 hours, against 14 to 20 hours in younger adults (SmPC 5.2).

Pregnancy and breastfeeding

It is contraindicated in both in the UK. Human data are inadequate to establish safety in early pregnancy. Foetal abnormalities occurred in animals at doses well above human doses. Hydroxyzine crosses the placenta and may reach higher levels in the foetus than in the mother. Babies exposed late in pregnancy or during labour have had floppiness, movement disorders, CNS depression, breathing problems and urinary retention (SmPC 4.6). The US label contraindicates it in early pregnancy and says it should not be given to nursing mothers (FDA label).

Liver and kidney problems

With liver impairment, the daily dose should be cut by a third, and it should be avoided in severe liver disease because of the risk of coma and hepatic encephalopathy. With moderate or severe kidney impairment, the dose should be halved, because the active metabolite cetirizine builds up (SmPC 4.2, 4.4).

Dosage and how to take it

Your prescriber sets the dose. The ranges below are the official licensed adult doses, given for reference only.

Situation Licensed dose Source
Anxiety, adults (UK) 50–100 mg a day in divided doses; maximum 100 mg a day UK SmPC, MHRA
Older adults (UK) Avoid; if it cannot be avoided, maximum 50 mg a day MHRA
Liver impairment Reduce the total daily dose by 33%; avoid in severe liver disease SmPC
Moderate or severe kidney impairment Reduce the total daily dose by 50% SmPC
Anxiety, adults (US label) 50–100 mg four times a day. This exceeds the post-2015 UK and EU maximum. FDA label
  • How soon it works: sedative effects usually begin within 15 to 30 minutes (SmPC).
  • How long to take it: regulators advise the shortest possible duration (MHRA). The FDA says effectiveness beyond 4 months has not been assessed and should be reviewed periodically (FDA label).
  • Stopping: discuss with your prescriber. Withdrawal symptoms were not more common than placebo in trials (Cochrane), but anxiety may return and movement problems have followed long-term use (SmPC).
  • Driving: do not drive or use machinery if you feel drowsy or your judgement is affected (SmPC 4.7).

Follow the money: who makes it and who funded the evidence

Who made it

Hydroxyzine was developed by UCB, a Belgian company. UCB's own history describes Atarax as a breakthrough from its pharmaceutical research centre, founded in 1952, and says that licensing US distribution of Atarax to Pfizer, then a small, young company, helped Pfizer grow into a pharmaceutical giant (UCB history). This is the company's own account. The Cochrane review, citing a 1998 source, says hydroxyzine was "synthesised in Belgium and put on the market in 1955" (Cochrane 2010). Pfizer held the first US approvals in 1956 and 1957 (Drugs@FDA).

Who sells it now

  • UK: in September 2026, the UK medicines compendium listed hydroxyzine tablets only from Morningside Healthcare Ltd (Leicester, UK) and Ipca Laboratories UK Ltd (emc, Morningside SmPC). The 2015 MHRA alert named the Atarax and Ucerax brands. We did not verify their current UK licence status.
  • US: Atarax and Vistaril are discontinued as brands. Generic hydroxyzine is sold by many companies; openFDA lists 110 application records for hydroxyzine hydrochloride (openFDA).
  • Revenue: we found no documented current sales figure. As a cheap generic, it offers little incentive for new company-funded trials.

Who funded the evidence

  • The efficacy trials: Cochrane reports that two of the five included trials were sponsored by the manufacturer, among them some of the most recent (Cochrane full text). We could not confirm from the abstract records which two, or whether the sponsor was UCB, so we label the Llorca 2002 and Lader 1998 trials as "funding not verified" rather than assigning a sponsor.
  • The independent review: the Cochrane review had internal support from the University of Verona and no external funding. Declarations of interest: "none known" (Cochrane 2010).
  • The safety evidence: the QT restrictions came from a regulator-led EU review (EMA), and the older-adult warnings from the American Geriatrics Society, which reported "no sponsor" (Beers 2023).

In short, the benefit evidence is partly industry-sponsored and old, and the safety evidence is regulator-led and newer. Both point the same way: hydroxyzine is a short-term, second-line option to be used cautiously, not a mainstay.

Frequently asked questions

How long does hydroxyzine take to work for anxiety?

The sedative, calming effect usually begins within 15 to 30 minutes and lasts about 4 to 6 hours (SmPC). In the trials, anxiety-scale improvements were measured over 4 to 12 weeks (Lader 1998, Llorca 2002).

Is hydroxyzine addictive like Xanax or diazepam?

It is not a benzodiazepine and not a controlled drug. In trials, withdrawal symptoms were no more common than on placebo, and older studies found no dependence or abuse potential (Cochrane 2010). Long-term evidence is limited, so regulators still advise the shortest possible use (MHRA).

Can you drink alcohol on hydroxyzine?

No. The UK product information says alcohol with hydroxyzine "should be avoided", because it increases sedation and impairment. The US label warns that the effects of alcohol may be increased (SmPC, FDA label).

Can I take hydroxyzine with sertraline, citalopram or escitalopram?

Citalopram and escitalopram are named in the UK product information as QT-prolonging antidepressants that must not be combined with hydroxyzine (SmPC 4.5). The US label also lists fluoxetine among drugs to use cautiously with it (FDA label). Any antidepressant can add to sedation. Your prescriber and pharmacist need to check your full list.

Does hydroxyzine cause weight gain?

Weight gain is listed as a possible side effect, with frequency not known (SmPC). The Cochrane review looked at weight gain among its side-effect outcomes and found no significant difference from comparators (Cochrane 2010).

Is hydroxyzine safe for older people?

Regulators and geriatric experts say to avoid it. The MHRA advises avoiding it in the elderly, with a 50 mg daily maximum if it cannot be avoided. The Beers Criteria recommend avoiding it because of anticholinergic effects linked to confusion, falls and delirium (MHRA, Beers 2023).

Can hydroxyzine be used for sleep?

It causes drowsiness, and some EU countries license it for sleep disorders (EMA). It is not licensed for insomnia in the UK (SmPC). The Beers Criteria note that tolerance develops when first-generation antihistamines are used as sleeping aids (Beers 2023).

How do I stop hydroxyzine safely?

Talk to your prescriber first. Trials did not find more withdrawal symptoms than placebo (Cochrane 2010). After prolonged use, abnormal movements (dyskinesia) have been reported on stopping, and your original anxiety may return, so your prescriber may reduce it gradually and plan other treatment (SmPC).

Sources and funding notes

Last reviewed: 26 September 2026. Educational information from Pure City Research, not medical advice. Medicine decisions belong with a qualified prescriber.

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