Hydroxyzine Orion
Hydroxyzine hydrochloride — First-generation antihistamine with anxiolytic properties
Quick Facts About Hydroxyzine Orion
Key Takeaways About Hydroxyzine Orion
- Dual-purpose medication: Hydroxyzine Orion treats both anxiety and allergic pruritus, making it versatile for patients with overlapping symptoms
- Causes significant drowsiness: Sedation is the most common side effect — do not drive or operate machinery until you know how it affects you
- QT prolongation risk: Higher doses may prolong the QT interval; use the lowest effective dose, especially in elderly patients and those with cardiac risk factors
- Contraindicated in pregnancy: Hydroxyzine should not be used during pregnancy due to potential teratogenic effects demonstrated in animal studies
- Metabolised to cetirizine: The liver converts hydroxyzine into cetirizine, a well-known second-generation antihistamine, via the CYP3A4 enzyme system
What Is Hydroxyzine Orion and What Is It Used For?
Hydroxyzine Orion is a first-generation antihistamine containing hydroxyzine hydrochloride. It is primarily prescribed for the management of anxiety and tension in adults, the symptomatic relief of pruritus (itching) associated with allergic conditions, and as a premedication before surgical or diagnostic procedures.
Hydroxyzine belongs to the piperazine class of compounds and acts as a competitive antagonist at peripheral and central histamine H1 receptors. Unlike many antihistamines that are used purely for allergic conditions, hydroxyzine possesses significant anxiolytic (anti-anxiety) and sedative properties, which makes it a valuable option in clinical settings where both anxiety and allergic symptoms need to be addressed simultaneously. The medication was first synthesised in 1956 and has been used clinically for over six decades, establishing a well-documented safety and efficacy profile.
The anxiolytic effect of hydroxyzine is particularly noteworthy because it does not carry the risk of dependence or withdrawal symptoms associated with benzodiazepines. This makes it an attractive alternative for the short-term management of generalised anxiety disorder, particularly in patients who are at risk for substance misuse or in whom benzodiazepines are contraindicated. Clinical trials have demonstrated that hydroxyzine is effective in reducing anxiety symptoms, with an onset of action within 15 to 30 minutes of oral administration.
For allergic conditions, hydroxyzine is effective in relieving pruritus associated with chronic urticaria (hives), atopic dermatitis (eczema), and contact dermatitis. The antipruritic effect is mediated through blockade of H1 receptors in the skin, reducing histamine-mediated itching, redness, and swelling. The sedative component can be particularly beneficial for patients whose pruritus disrupts sleep, as the medication can be dosed at bedtime to provide overnight relief and improve sleep quality.
Hydroxyzine Orion is also used in perioperative settings as a premedication. Its combined sedative, anxiolytic, and antiemetic (anti-nausea) properties make it useful for reducing preoperative anxiety and contributing to smoother anaesthetic induction. In some protocols, it is administered alongside opioid analgesics to potentiate their pain-relieving effects while simultaneously reducing opioid-induced nausea and vomiting.
After oral administration, hydroxyzine is rapidly and completely absorbed from the gastrointestinal tract. Peak plasma concentrations are achieved within approximately 2 hours. It is extensively metabolised in the liver, primarily by the cytochrome P450 enzyme CYP3A4, yielding cetirizine as its principal active metabolite. Cetirizine itself is a widely used second-generation antihistamine. The elimination half-life of hydroxyzine in adults is approximately 14 to 20 hours, allowing for once- or twice-daily dosing depending on the indication.
What Should You Know Before Taking Hydroxyzine Orion?
Before taking Hydroxyzine Orion, you must inform your doctor about all medical conditions, particularly heart problems, liver or kidney disease, epilepsy, glaucoma, and prostate enlargement. Hydroxyzine is contraindicated in pregnancy, during breastfeeding, and in patients with known QT prolongation.
As with all prescription medications, there are important factors that must be considered before starting treatment with Hydroxyzine Orion. Your prescribing physician will need a complete medical history to determine whether hydroxyzine is appropriate for you and to select the correct dose. Open communication about your current medications, supplements, and health conditions is essential for safe prescribing.
Contraindications
Hydroxyzine Orion must not be used in the following circumstances:
- Hypersensitivity: Known allergy to hydroxyzine, cetirizine, other piperazine derivatives, or any of the tablet's excipients
- Pregnancy: Hydroxyzine is contraindicated throughout all trimesters of pregnancy due to potential teratogenic effects observed in animal studies
- Breastfeeding: Hydroxyzine and its metabolite cetirizine are excreted in breast milk and may cause sedation or irritability in the nursing infant
- Porphyria: Hydroxyzine may exacerbate acute attacks of porphyria
- Known QT prolongation: Patients with congenital or acquired long QT syndrome must not use hydroxyzine
- Significant cardiovascular disease: Patients with recent myocardial infarction, uncompensated heart failure, or clinically significant bradycardia
Warnings and Precautions
Special care is needed if you have any of the following conditions, as dose adjustments or additional monitoring may be required:
- Hepatic impairment: Hydroxyzine is extensively metabolised in the liver. Patients with reduced liver function may experience prolonged and intensified effects and should receive lower doses
- Renal impairment: Dose reduction is recommended in patients with moderate to severe kidney disease, as the clearance of the active metabolite cetirizine is reduced
- Elderly patients: Older adults are more susceptible to the anticholinergic and sedative effects of hydroxyzine. A lower starting dose (typically half the standard adult dose) is recommended, and the duration of treatment should be as short as possible
- Seizure disorders: Hydroxyzine may lower the seizure threshold. Use with caution in patients with epilepsy or a history of convulsions
- Angle-closure glaucoma: The anticholinergic properties of hydroxyzine can increase intraocular pressure, potentially worsening glaucoma
- Urinary retention and prostatic hyperplasia: Anticholinergic effects may worsen urinary obstruction
- Myasthenia gravis: Anticholinergic drugs may exacerbate muscle weakness in this condition
- Electrolyte imbalances: Hypokalaemia or hypomagnesaemia increases the risk of cardiac arrhythmias, including QT prolongation
Hydroxyzine has been associated with dose-dependent QT interval prolongation on electrocardiograms (ECGs). The risk increases at higher doses, in elderly patients, in patients with pre-existing cardiac conditions, and when co-administered with other QT-prolonging medications. Your doctor should use the lowest effective dose for the shortest possible duration. ECG monitoring may be appropriate for patients with cardiac risk factors.
Pregnancy and Breastfeeding
Hydroxyzine Orion is classified as contraindicated during pregnancy. Animal reproduction studies have demonstrated adverse effects on the foetus, including skeletal abnormalities at doses exceeding those used therapeutically. Although controlled human studies are limited, the potential risk to the developing foetus means that hydroxyzine should not be used at any stage of pregnancy. Women of childbearing potential should be advised to use effective contraception during treatment.
Hydroxyzine and its active metabolite cetirizine pass into breast milk. Given the potential for sedation, irritability, and anticholinergic effects in the nursing infant, breastfeeding should be discontinued if hydroxyzine treatment is necessary. If the condition being treated is primarily allergic pruritus, safer alternatives such as topical treatments or second-generation antihistamines with lower sedation profiles should be considered during breastfeeding.
If you are planning a pregnancy, are pregnant, or suspect you may be pregnant, contact your healthcare provider immediately for guidance on discontinuation and alternative treatment options. Hydroxyzine should be tapered gradually under medical supervision rather than stopped abruptly, particularly if it has been used for anxiety management.
How Does Hydroxyzine Orion Interact with Other Drugs?
Hydroxyzine Orion interacts significantly with CNS depressants (including alcohol, opioids, and benzodiazepines), anticholinergic agents, and drugs that prolong the QT interval. CYP3A4 inhibitors can increase hydroxyzine plasma levels. Always provide your doctor with a complete list of all medications you take.
Drug interactions are an important consideration when using hydroxyzine, as the medication affects multiple physiological pathways. The most clinically significant interactions involve other central nervous system (CNS) depressants, medications with anticholinergic properties, drugs that affect cardiac repolarisation (QT interval), and inhibitors of the CYP3A4 enzyme system. Understanding these interactions is critical for preventing potentially dangerous adverse effects.
Hydroxyzine is primarily metabolised by the hepatic cytochrome P450 enzyme CYP3A4. Drugs that inhibit this enzyme can significantly increase hydroxyzine plasma concentrations, potentially enhancing both therapeutic and adverse effects. Conversely, CYP3A4 inducers may reduce hydroxyzine efficacy by accelerating its metabolism. Your prescribing physician and pharmacist will review your medication list for potential interactions before starting treatment.
Major Interactions
| Drug / Class | Interaction Effect | Clinical Action |
|---|---|---|
| Alcohol (ethanol) | Marked potentiation of CNS depression; increased sedation, impaired coordination, respiratory depression risk | Avoid alcohol completely during treatment |
| Opioid analgesics (codeine, morphine, tramadol, oxycodone) | Additive CNS and respiratory depression; increased risk of fatal respiratory depression | Reduce opioid dose by 50%; monitor respiratory function closely |
| Benzodiazepines (diazepam, alprazolam, lorazepam) | Enhanced sedation, respiratory depression, psychomotor impairment | Avoid combination if possible; reduce doses of both drugs if concurrent use is essential |
| QT-prolonging drugs (amiodarone, sotalol, haloperidol, ondansetron) | Additive QT prolongation; risk of torsades de pointes and sudden cardiac death | Avoid combination; if unavoidable, perform ECG monitoring and use lowest doses |
| MAO inhibitors (phenelzine, tranylcypromine, moclobemide) | Potentiation of anticholinergic effects; risk of hypotension and excessive sedation | Avoid concurrent use; allow adequate washout period |
| CYP3A4 inhibitors (ketoconazole, itraconazole, erythromycin, clarithromycin) | Increased hydroxyzine plasma concentrations; enhanced sedation and QT prolongation risk | Reduce hydroxyzine dose; consider alternative antifungal or antibiotic |
Minor Interactions
| Drug / Class | Interaction Effect | Clinical Action |
|---|---|---|
| Anticholinergic drugs (atropine, ipratropium, oxybutynin) | Additive anticholinergic effects: dry mouth, constipation, urinary retention, blurred vision | Monitor for anticholinergic burden; consider alternatives |
| Phenytoin | Hydroxyzine may inhibit phenytoin metabolism, increasing phenytoin levels | Monitor phenytoin levels; adjust dose as needed |
| Betahistine | Hydroxyzine may partially counteract the effects of betahistine | Avoid concurrent use in patients being treated for vertigo |
| Cholinesterase inhibitors (donepezil, rivastigmine) | Anticholinergic properties of hydroxyzine may reduce efficacy of cholinesterase inhibitors | Avoid combination in patients with dementia |
This is not an exhaustive list of all possible interactions. Always inform your doctor and pharmacist about all prescription and over-the-counter medications, herbal supplements, and vitamins you are taking. Certain herbal remedies, including St John's wort (a CYP3A4 inducer) and valerian root (a CNS depressant), may also interact with hydroxyzine.
What Is the Correct Dosage of Hydroxyzine Orion?
The dosage of Hydroxyzine Orion is individualised based on the patient's age, condition being treated, and response to therapy. Adults typically start with 25–50 mg daily for anxiety and 25 mg at bedtime for pruritus, while elderly patients require reduced doses. The lowest effective dose should be used for the shortest possible duration.
Correct dosing of hydroxyzine is essential for achieving therapeutic benefit while minimising the risk of adverse effects, particularly sedation and QT prolongation. The European Medicines Agency (EMA) has issued recommendations to limit the maximum dose and duration of treatment, especially in vulnerable populations such as the elderly and patients with hepatic or renal impairment. Your doctor will determine the most appropriate dose based on your individual clinical circumstances.
Adults
Anxiety and Tension
Starting dose: 25–50 mg daily, divided into 2–3 doses or given as a single dose at bedtime.
Maintenance dose: 50–100 mg daily in divided doses, adjusted according to response.
Maximum dose: 100 mg per day (EMA recommendation). Individual doses should not exceed 50 mg.
Pruritus (Itching)
Starting dose: 25 mg at bedtime. May be increased to 25 mg 2–3 times daily.
Maintenance dose: 25–75 mg daily in divided doses.
Maximum dose: 100 mg per day.
Premedication (Before Surgery)
Dose: 50–100 mg as a single dose, administered 1 hour before the procedure.
Note: Given in addition to any other prescribed premedication agents.
Children
Hydroxyzine Orion may be prescribed to children for specific indications under specialist supervision. Dosing in children is based on body weight:
Children (Age 6–12 years)
Pruritus: 1 mg/kg/day in divided doses, up to a maximum of 50 mg daily.
Premedication: 1 mg/kg as a single dose, administered 1 hour before the procedure.
Children Under 6 Years
Use in children under 6 years of age is generally not recommended. When deemed necessary by a specialist, the dose is 1 mg/kg/day in divided doses, not to exceed 2 mg/kg/day.
Hydroxyzine Orion 10 mg film-coated tablets may not be suitable for achieving accurate dosing in very young children or those requiring doses below 10 mg. Liquid formulations may be more appropriate in such cases. Always follow your paediatrician's specific dosing instructions.
Elderly Patients
Elderly patients are particularly sensitive to the effects of hydroxyzine due to age-related changes in drug metabolism, increased blood-brain barrier permeability, and greater susceptibility to anticholinergic side effects. The EMA recommends the following precautions:
- Starting dose: Half the standard adult dose (e.g., 12.5 mg or one half of a 25 mg tablet, where available)
- Maximum dose: 50 mg per day
- Duration: Treatment should be as short as possible
- Monitoring: Regular assessment of cognitive function, fall risk, and cardiac rhythm is recommended
The anticholinergic burden in elderly patients is a significant concern. Hydroxyzine contributes to this burden and, when combined with other anticholinergic medications, can increase the risk of confusion, delirium, cognitive impairment, falls, and urinary retention. Healthcare providers should regularly review the total anticholinergic load in elderly patients and consider whether hydroxyzine remains necessary.
Missed Dose
If you miss a dose of Hydroxyzine Orion, take it as soon as you remember. However, if it is nearly time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are unsure about what to do, consult your pharmacist or doctor.
Overdose
Overdose with hydroxyzine can be serious and potentially life-threatening. Symptoms of overdose include profound sedation, coma, respiratory depression, seizures, hypotension, and cardiac arrhythmias (including QT prolongation and torsades de pointes). If overdose is suspected, seek emergency medical attention immediately. Treatment is primarily supportive, with cardiac monitoring and management of symptoms. There is no specific antidote for hydroxyzine overdose. Activated charcoal may be considered if the patient presents within 1 hour of ingestion.
What Are the Side Effects of Hydroxyzine Orion?
The most common side effects of Hydroxyzine Orion are drowsiness and sedation, affecting more than 1 in 10 patients. Other frequently reported effects include dry mouth, headache, fatigue, and dizziness. Serious but rare side effects include QT prolongation, severe allergic reactions, and seizures. Most side effects are dose-dependent and may diminish with continued use.
Like all medicines, Hydroxyzine Orion can cause side effects, although not everybody gets them. The side effects of hydroxyzine are primarily related to its pharmacological actions: histamine H1 receptor blockade, anticholinergic (antimuscarinic) effects, and central nervous system depression. Many of these effects are dose-dependent, meaning they are more likely to occur at higher doses and in susceptible populations such as the elderly.
It is important to distinguish between expected pharmacological effects (such as drowsiness, which is a predictable consequence of H1 blockade in the brain) and true adverse reactions. Drowsiness is often a desired therapeutic effect when hydroxyzine is used for anxiety or pruritus at bedtime, but it becomes an adverse effect when it impairs daytime functioning. Tolerance to the sedative effect typically develops within the first few days of treatment.
Very Common (more than 1 in 10 patients)
- Drowsiness and sedation
- Fatigue and lethargy
Common (1 in 10 to 1 in 100 patients)
- Dry mouth (xerostomia)
- Headache
- Dizziness
- Nausea
- Blurred vision
- Constipation
- Difficulty with urination (urinary retention)
Uncommon (1 in 100 to 1 in 1,000 patients)
- Skin rash or urticaria
- Insomnia (paradoxical reaction)
- Agitation or restlessness
- Tremor
- Increased sweating
- Tachycardia (fast heart rate)
- Weight gain
Rare (fewer than 1 in 1,000 patients)
- QT prolongation and cardiac arrhythmias
- Severe allergic reactions (anaphylaxis, angioedema)
- Seizures (particularly in predisposed individuals)
- Hepatic dysfunction (elevated liver enzymes)
- Fixed drug eruption
- Hallucinations or confusion (mainly in elderly)
- Acute generalised exanthematous pustulosis (AGEP)
If you experience any serious side effects, particularly chest pain, palpitations, fainting, difficulty breathing, or severe skin reactions, discontinue hydroxyzine immediately and seek emergency medical attention. For less serious side effects that are bothersome or persistent, contact your prescribing physician to discuss dose adjustment or alternative treatments.
You can help ensure the safe use of medications by reporting any side effects to your national pharmacovigilance authority. In the EU, side effects can be reported through the national reporting systems listed on the EMA website. In the UK, you can report via the Yellow Card Scheme. In the US, contact the FDA MedWatch programme.
How Should You Store Hydroxyzine Orion?
Store Hydroxyzine Orion at room temperature below 25°C (77°F), in the original packaging to protect from moisture and light. Keep out of the sight and reach of children. Do not use after the expiry date printed on the packaging.
Proper storage of medications is essential to maintain their potency, safety, and effectiveness throughout the stated shelf life. Hydroxyzine Orion film-coated tablets should be stored under controlled conditions to prevent degradation of the active ingredient and excipients. Exposure to excessive heat, humidity, or light can alter the chemical composition of the tablets, potentially reducing their efficacy or creating harmful degradation products.
Store the tablets in their original blister packaging or container at a temperature not exceeding 25°C (77°F). Do not store in the bathroom, kitchen, or other areas subject to temperature fluctuations and high humidity. The tablets should be kept in a secure location that is inaccessible to children and pets. If you notice any visible changes in the appearance of the tablets, such as discolouration, crumbling, or unusual odour, do not take them and return them to your pharmacy for safe disposal.
Do not use Hydroxyzine Orion after the expiry date stated on the carton and blister strips. The expiry date refers to the last day of that month. Unused or expired medications should not be disposed of via household waste or wastewater. Return them to a pharmacy or local medication take-back programme for environmentally responsible disposal. This helps prevent environmental contamination and accidental ingestion by others.
What Does Hydroxyzine Orion Contain?
Each Hydroxyzine Orion film-coated tablet contains 10 mg of hydroxyzine hydrochloride as the active ingredient, along with several inactive excipients that form the tablet core and film coating. The excipients include lactose monohydrate, microcrystalline cellulose, and other standard pharmaceutical ingredients.
Understanding the full composition of your medication is important, particularly if you have known allergies or intolerances to specific pharmaceutical excipients. The complete qualitative and quantitative composition of Hydroxyzine Orion 10 mg film-coated tablets is as follows:
Active substance: Each film-coated tablet contains 10 mg of hydroxyzine hydrochloride, equivalent to approximately 8.5 mg of hydroxyzine base.
Tablet core excipients (typical):
- Lactose monohydrate — filler/diluent (important for patients with lactose intolerance)
- Microcrystalline cellulose — binder and filler
- Colloidal anhydrous silica — glidant (aids tablet flow during manufacturing)
- Magnesium stearate — lubricant
- Sodium starch glycolate — disintegrant (helps the tablet break down after swallowing)
Film coating excipients (typical):
- Hypromellose — film-forming agent
- Titanium dioxide (E171) — opacifier and white colourant
- Macrogol — plasticiser for the coating
Hydroxyzine Orion tablets contain lactose monohydrate. Patients with rare hereditary problems of galactose intolerance, total lactase deficiency, or glucose-galactose malabsorption should not take this medicine. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product.
Frequently Asked Questions About Hydroxyzine Orion
Hydroxyzine Orion is a first-generation antihistamine used to treat anxiety and tension in adults, pruritus (itching) associated with allergic conditions such as urticaria and dermatitis, and as a premedication before surgical or diagnostic procedures. It works by blocking H1 histamine receptors in the body and has additional sedative and anxiolytic properties.
Hydroxyzine Orion is rapidly absorbed after oral administration and typically begins to take effect within 15 to 30 minutes. Peak plasma concentrations are reached approximately 2 hours after ingestion. The sedative and anti-anxiety effects may be felt within 30 minutes, while antipruritic effects usually develop within 1 hour.
Yes, drowsiness and sedation are the most common side effects of Hydroxyzine Orion, reported in more than 1 in 10 patients. Because of this, you should not drive or operate machinery until you know how the medicine affects you. The sedative effect is usually most pronounced during the first few days of treatment and may diminish with continued use.
Hydroxyzine Orion should not be used during pregnancy. Animal studies have shown potential teratogenic effects, and hydroxyzine crosses the placental barrier. It is classified as contraindicated in pregnancy by the EMA. Women of childbearing potential should use effective contraception during treatment. If pregnancy is suspected, the medication should be discontinued and a healthcare provider consulted immediately.
Cetirizine is actually the main active metabolite of hydroxyzine. When you take hydroxyzine, your liver converts it into cetirizine through the CYP3A4 enzyme system. The key difference is that hydroxyzine crosses the blood-brain barrier and causes significant sedation, while cetirizine is a second-generation antihistamine that causes much less drowsiness. Hydroxyzine has anxiolytic (anti-anxiety) properties that cetirizine lacks, making hydroxyzine useful for anxiety, while cetirizine is preferred for long-term allergy treatment without sedation.
No, you should avoid alcohol completely while taking Hydroxyzine Orion. Alcohol significantly enhances the sedative effects of hydroxyzine, potentially causing excessive drowsiness, impaired coordination, dangerously slowed reflexes, and respiratory depression. This combination also increases the risk of QT prolongation. If you have questions about alcohol consumption during treatment, consult your prescribing physician.
References and Medical Sources
This article is based on the following internationally recognised medical sources and guidelines. All medical claims are evidence-based and peer-reviewed:
- European Medicines Agency (EMA). Hydroxyzine-containing medicinal products — Referral under Article 31 of Directive 2001/83/EC. EMA/224192/2015. Published 2015. Available at: www.ema.europa.eu
- World Health Organization (WHO). WHO Model List of Essential Medicines — 23rd List. Geneva: WHO; 2023.
- British National Formulary (BNF). Hydroxyzine hydrochloride: drug monograph. National Institute for Health and Care Excellence (NICE). Updated 2025.
- Guaiana G, Barbui C, Cipriani A. Hydroxyzine for generalised anxiety disorder. Cochrane Database of Systematic Reviews. 2010;(12):CD006815. doi:10.1002/14651858.CD006815.pub2
- Simons FER, Simons KJ. Histamine and H1-antihistamines: celebrating a century of progress. Journal of Allergy and Clinical Immunology. 2011;128(6):1161–1174. doi:10.1016/j.jaci.2011.09.005
- 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;5(3):e00309. doi:10.1002/prp2.309
- 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. Journal of Clinical Psychiatry. 2002;63(11):1020–1027.
- FDA Drug Safety Communication. Antihistamines and cardiac risk: safety review. U.S. Food and Drug Administration. Updated 2024.
About the Medical Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, consisting of licensed physicians specialising in clinical pharmacology, internal medicine, and evidence-based therapeutics. Our editorial process follows international medical writing standards, and all content is reviewed according to the GRADE evidence framework.
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