Atarax® - (IR): composition and pharmaceutical form
Atarax® - (IR) comes as film-coated tablets. One tablet contains 10 mg or 25 mg of hydroxyzine hydrochloride — two strengths that allow the dose to be adjusted in small steps.
The tablets contain lactose, so they are unsuitable for patients with hereditary galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption syndrome.
How Atarax® - (IR) works
Hydroxyzine hydrochloride does not depress the activity of the cerebral cortex: its action appears to be linked to inhibition of the activity of certain subcortical areas of the central nervous system. The antihistamine and bronchodilator effects are confirmed experimentally and clinically, and the antiemetic action has been shown in the apomorphine and veratrole tests.
In healthy adult volunteers and in children the medicine reduced the wheal-and-flare reaction after intradermal administration of histamine or antigens, and also proved able to reduce itching in various forms of urticaria, eczema and dermatitis. At therapeutic doses hydroxyzine does not increase the production or acidity of gastric juice and in most cases produces a mild antisecretory effect. In hepatic impairment the antihistamine action of a single dose may last up to 96 hours.
Indications
The medicine is used for the symptomatic treatment of anxiety in adults, the symptomatic treatment of itching and premedication before surgical procedures.
In every case this is symptomatic help: hydroxyzine reduces anxiety and itching but does not remove their cause. That is precisely why the lowest effective dose is used and the course is kept as short as possible.
Method of use and dosage
The dose is chosen individually within the recommended range, guided by the patient's response. In adults and children with a body weight above 40 kg the maximum daily dose is 100 mg.
| Situation | Dose |
|---|---|
| Symptomatic treatment of anxiety in adults | 50 mg a day in 2–3 intakes; in severe cases up to 100 mg a day |
| Symptomatic treatment of itching | Start with 25 mg before sleep and, if needed, increase to 25 mg 3–4 times a day |
| Premedication before an operation | 50 mg in two intakes or 100 mg as a single oral dose |
| Children from 12 months: itching | From 1 to 2 mg per kg of body weight a day in several intakes |
| Children from 12 months: premedication | 0.6 mg per kg of body weight orally as a single dose, no more than 2 mg/kg a day in total |
Special patient groups
In children and adolescents weighing up to 40 kg the maximum daily dose is 2 mg per kg and, above 40 kg, 100 mg. Hydroxyzine is not recommended for elderly people: elimination in them is slower and the risk of adverse reactions, above all anticholinergic ones, is higher; if the doctor does prescribe treatment, it begins with half the usual dose and the maximum daily dose is 50 mg. In hepatic impairment the daily dose is reduced by a third. In moderate and severe renal impairment the dose is also lowered, because of the slowed elimination of the metabolite, cetirizine.
Contraindications
The medicine is not prescribed in the following cases:
- hypersensitivity to hydroxyzine or to any excipient, to cetirizine, to other piperazine derivatives, to aminophylline or to ethylenediamine;
- porphyria;
- known congenital or acquired prolongation of the QT interval;
- known risk factors for QT prolongation: cardiovascular disease, significant electrolyte disturbances (hypokalaemia, hypomagnesaemia), cases of sudden cardiac death in the family, marked bradycardia;
- concomitant use of medicines that prolong the QT interval or cause torsade de pointes arrhythmia;
- pregnancy and the breastfeeding period.
Special warnings and precautions
The main cardiac problem with hydroxyzine is prolongation of the QT interval. After the medicine reached the market, cases of QT prolongation and of torsade de pointes arrhythmia were recorded; most of those patients had additional risk factors — electrolyte disturbances and the concomitant use of other medicines. The lowest effective dose and the shortest possible course are therefore used and, if symptoms appear that may be linked to a rhythm disturbance, treatment is stopped and a doctor contacted immediately. The patient is warned in advance that any cardiac complaint must be reported straight away.
- caution is needed with a heightened tendency to seizures: in children seizures were recorded more often than in adults, and small children are in general more vulnerable to the medicine's effect on the central nervous system;
- because of its anticholinergic action, caution is required in glaucoma, difficulty emptying the bladder, weakened intestinal peristalsis, myasthenia and dementia;
- with the concomitant use of other agents that depress the central nervous system, or of medicines with anticholinergic properties, a dose adjustment may be needed;
- alcohol is excluded during treatment — it enhances the action of hydroxyzine;
- the medicine is not recommended for elderly patients, and in hepatic and moderate or severe renal impairment the dose is reduced;
- before skin allergy tests and the bronchial provocation test with methacholine the medicine is stopped at least 5 days beforehand, otherwise the results will be distorted.
No specific studies of the influence on the ability to drive have been carried out, but hydroxyzine causes fatigue, dizziness, sedation and visual disturbances and therefore has a moderate or considerable influence on reaction speed and concentration — especially at high doses and together with alcohol or sedatives. Every patient is warned about this.
Drug interactions
Combination is contraindicated with medicines that prolong the QT interval or cause torsade de pointes arrhythmia: class IA antiarrhythmics (quinidine, disopyramide) and class III (amiodarone, sotalol), some antihistamines and antipsychotics, for example haloperidol, certain antidepressants (citalopram, escitalopram), antimalarials (mefloquine, hydroxychloroquine), a number of antibiotics (erythromycin, levofloxacin, moxifloxacin), pentamidine, prucalopride, some antineoplastic agents (toremifene, vandetanib) and methadone. Caution is also needed with medicines that cause bradycardia or hypokalaemia.
Agents that depress the central nervous system and medicines with anticholinergic action enhance the effect of hydroxyzine, and in such cases the dose is chosen individually; alcohol also enhances its action. Hydroxyzine itself acts as an antagonist of betahistine and of cholinesterase inhibitors and weakens the pressor action of adrenaline. Concomitant use with MAO inhibitors should be avoided. Cimetidine at 600 mg twice a day raised the serum concentration of hydroxyzine by 36% and lowered the concentration of cetirizine by 20%. Hydroxyzine inhibits CYP2D6 and at high doses may interact with the substrates of that enzyme; it is itself metabolised by alcohol dehydrogenase and CYP3A4/5, so strong inhibitors of those enzymes raise its blood concentration.
Pregnancy and breastfeeding
Hydroxyzine is contraindicated in pregnancy, and women of childbearing age must use reliable contraception during treatment. Animal studies have revealed reproductive toxicity; the medicine crosses the placenta and reaches a higher concentration in the foetus than in the mother. There are at present no significant epidemiological data on use in pregnancy.
In newborns whose mothers received hydroxyzine late in pregnancy or during labour, muscular hypotonia, movement disorders including extrapyramidal ones, clonic movements, depression of the central nervous system, hypoxia and urinary retention were seen immediately or a few hours after birth. Cetirizine, the main metabolite of hydroxyzine, passes into breast milk; standard studies of the excretion of hydroxyzine itself in milk have not been carried out, but severe adverse reactions were seen in children breastfed by mothers taking the medicine. Hydroxyzine is therefore contraindicated while breastfeeding and, if treatment is necessary, breastfeeding is stopped.
Adverse effects
Adverse reactions relate above all to the depressant or, conversely, paradoxically stimulating action on the central nervous system, to the anticholinergic action and to hypersensitivity reactions. In placebo-controlled studies at a dose of 50 mg a day, the most frequent were drowsiness, headache, dry mouth and fatigue.
- common — sedation;
- uncommon — agitation, confusion, dizziness, insomnia, tremor;
- rare — disorientation, hallucinations, seizures, dyskinesia, disturbances of accommodation, blurred vision, tachycardia, hypersensitivity reactions;
- very rare — anaphylactic shock;
- frequency not known — fainting, ventricular rhythm disturbances including torsade de pointes, and prolongation of the QT interval;
- reactions known for cetirizine and possible with hydroxyzine — thrombocytopenia, aggression, depression, tics, dystonia, paraesthesia, oculogyric crises;
- also for cetirizine — diarrhoea, difficulty passing urine and urinary incontinence, asthenia, oedema, weight gain.
Overdose
The symptoms of a significant overdose relate mainly to excessive anticholinergic action and to depression or paradoxical excitation of the central nervous system: nausea, vomiting, tachycardia, fever, drowsiness, disturbed pupillary reflex, tremor, confusion or hallucinations. Then a fall in the level of consciousness, respiratory depression, seizures, a fall in blood pressure, heart rhythm disturbances including bradycardia, deepening coma and cardiovascular collapse are possible.
With a significant overdose, strict control of the airway, breathing and circulation is needed, with continuous ECG recording and sufficient oxygen; monitoring of heart rhythm and blood pressure continues for 24 hours, until the symptoms disappear. In patients with disturbed consciousness it is established whether other medicines or alcohol were taken at the same time and, if necessary, oxygen, naloxone, glucose and thiamine are given. If a vasoconstrictor is needed, noradrenaline or metaraminol is used; adrenaline is contraindicated. Emetics are not used where consciousness is disturbed, in coma or with seizures because of the danger of aspiration pneumonia, and gastric lavage, with a clinically significant intake, is performed after tracheal intubation.
How to get a prescription for Atarax® - (IR) online
Hydroxyzine is a prescription-only medicine: before prescribing it the doctor must assess the state of the heart, the medicines being taken and the risk factors for QT prolongation.
During the online consultation the doctor will go through your symptoms, choose the dose and the length of the course and, if there are no contraindications, issue an electronic prescription — the medicine can be collected at a pharmacy with its code.
