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- ATARAX / ATARAX Composition Active ingredient: Hydroxyzine hydrochloride 25mg. Excipients: Lactose monohydrate 54.80mg, microcrystalline cellulose 28.00mg, magnesium stearate 1.50mg, colloidal silicon dioxide (anhydrous) 0.70mg. Coating: Opadry® Y-1-7000 3.30mg (titanium dioxide 0.21mg, hypromellose 2.06mg, macrogol 400 1.03mg). Description Film-coated, oblong, white tablets, with a cross score on both sides. Pharmacotherapeutic group: Anxiolytic agent (tranquilizer). ATC code: N05BB01. See blog: What is Atarax used for and what should we know about this preparation Pharmacological properties Pharmacodynamics Diphenylmethane derivative, suppresses the activity of certain subcortical zones. It has H1-antihistamine, bronchodilatory, and antiemetic effects, and moderately affects gastrointestinal secretion. Hydroxyzine significantly reduces itching in patients with urticaria, eczema, and dermatitis. In liver failure, after a single dose, the H1-antihistamine effect can be prolonged up to 96 hours. It has moderate anxiolytic activity and a sedative effect. Polysomnography in patients with insomnia and anxiety reveals an increase in sleep duration and a reduction in nocturnal arousal after single or repeated administration of hydroxyzine at a dose of 50mg. In patients with anxiety, a reduction in muscle tension is observed when the preparation is taken at a dose of 50mg 3 times a day. It does not cause psychological dependence or addiction. Long-term use does not lead to withdrawal syndrome or cognitive impairment. The H1-antihistamine effect occurs approximately 1 hour after taking the tablet. The sedative effect appears after 30-45 minutes. It has antispasmodic and sympatholytic effects, as well as moderate analgesic action. Pharmacokinetics Absorption Absorption is high after oral administration. Time to reach maximum concentration (Tmax) is 2 hours. After a single dose of 25mg in adults, Tmax is 30ng/ml, and 70ng/ml after taking 50mg of hydroxyzine. Bioavailability after oral administration is 80%. Distribution Hydroxyzine is more concentrated in tissues than in plasma. The distribution coefficient is 7-16 L/kg in adults. After oral administration, hydroxyzine penetrates the skin well, with its concentration in the skin greatly exceeding its concentration in the blood, both after single and multiple doses. Hydroxyzine crosses the blood-brain barrier and the placenta, and is more concentrated in fetal than in maternal tissues. Metabolism Hydroxyzine is metabolized in the liver. Cetirizine, the main metabolite (45%), is a peripheral H1-histamine receptor blocker. Metabolites are detected in lactate. Elimination Half-life (T1/2) in adults is 14 hours (range: 7-20 hours). The total clearance of hydroxyzine is 13 ml/min/kg. Only 0.8% of hydroxyzine is excreted unchanged by the kidneys. The main metabolite, cetirizine, is mainly excreted in the urine unchanged (25% of the administered dose). Pharmacokinetics in Special Patient Groups In elderly patients, T1/2 was 29 hours, and the volume of distribution was 22.5 L/kg. When administered to elderly patients, a reduction in the daily dose of hydroxyzine is recommended. In children, total clearance is 2.5 times higher than in adults. The half-life (T1/2) is shorter than in adults: 11 hours in children aged 14 years and 4 hours at 1 year of age. Dose adjustment should be made when used in children. In patients with liver failure, in patients with secondary liver dysfunction due to primary biliary cirrhosis, total clearance is approximately 66% of the value registered in healthy volunteers. In patients with liver disease, T1/2 increased up to 37 hours, and the concentration of metabolites in serum is higher than in young patients with normal liver function. In patients with liver failure, it is recommended to reduce the daily dose or duration of administration. In patients with renal failure, the pharmacokinetics of hydroxyzine were studied in 8 patients with severe renal failure (creatinine clearance 24 ± 7 ml/min). The duration of hydroxyzine exposure (AUC) did not change significantly, while the exposure to the carboxylated metabolite, cetirizine, increased. Hemodialysis is ineffective for the excretion of this metabolite. To prevent the accumulation of the metabolite cetirizine after repeated administration of hydroxyzine in patients with impaired renal function, it is recommended to reduce the daily dose of hydroxyzine. Indications • Symptomatic treatment of anxiety in adults • As a sedative agent during premedication • Symptomatic treatment of itching of allergic origin Contraindications • Hypersensitivity to any component of the preparation, to cetirizine and other piperazine derivatives, aminophylline or ethylenediamine • Porphyria • Children under 3 years of age • Pregnancy, childbirth or lactation period • Hereditary galactose intolerance, lactase deficiency or glucose-galactose malabsorption syndrome (as the tablets contain lactose). • Prolonged QT interval in history. Precautions In myasthenia gravis, with difficulty urinating due to benign prostatic hyperplasia, constipation, glaucoma, dementia, predisposition to seizures, predisposition to arrhythmias, including electrolyte imbalance (hypokalemia, hypomagnesemia) in patients with a history of heart disease or when using preparations that can cause arrhythmias. Method of administration and dosage Oral Children For symptomatic treatment of itching of allergic origin: In children aged 3 to 6 years: 1mg/kg per day - 2.5mg/kg/day in several doses. In children aged 6 years and older: 1mg/kg/day - 2.0mg/kg/day in several doses. For premedication - 1mg/kg at night before anesthesia. The number of tablets is determined by the doctor based on the child's weight, according to the recommended doses. Adults For symptomatic treatment of anxiety: Standard dose 50mg per day, divided into 3 doses (½ tablet (12.5mg) in the morning, ½ tablet (12.5mg) in the afternoon, and 1 tablet (25mg) at night). In severe cases, the dose can be increased up to 12 tablets (300mg) per day. For symptomatic treatment of itching of allergic origin: Initial dose 1 tablet (25mg) before bedtime, if necessary, the dose can be increased to 1 tablet (25mg) 3-4 times a day. For premedication in surgical practice: 2-8 tablets (50-200mg) at night before anesthesia. The maximum single dose for an adult should not exceed 8 tablets (200mg), the maximum daily dose should not exceed 12 tablets (300mg). Use in Special Patient Groups The dose is selected individually, depending on the patient's response to treatment, within the recommended dosage range. Use in the elderly In elderly patients, treatment is started with half the dose. For symptomatic treatment of anxiety: ½ tablet (12.5mg) in the morning and ½ tablet (12.5mg) in the evening. For symptomatic treatment of itching of allergic origin: Initial dose ½ tablet (12.5mg) before bedtime, if necessary, the dose can be increased to ½ tablet (12.5mg) 3-4 times a day. For premedication in surgical practice: 1-4 tablets (25-100mg) at night before anesthesia. Use in patients with renal failure and impaired liver function In patients with moderate and severe renal failure, as well as liver failure, dose reduction is necessary. In patients with liver failure, a 33% reduction in the daily dose is recommended. In patients with moderate renal failure, dose reduction is recommended due to decreased excretion of the main metabolite of hydroxyzine, cetirizine. It is necessary to reduce the dose of hydroxyzine or increase the interval between administrations in proportion to the decrease in creatinine clearance, for example: half the daily dose in moderate renal failure and a quarter in severe failure. Safety precautions When using preparations with M-cholinergic blocking properties and in combination with CNS depressants, it is necessary to reduce the dose of hydroxyzine. In case of renal and/or liver failure, doses should be reduced. If allergy tests and methacholine tests are necessary, the administration of the preparation should be discontinued 5 days before the examination to avoid distorted results. Alcohol consumption should be avoided during hydroxyzine treatment. Overdose Symptoms observed after significant overdose of the preparation are related to strong M-cholinergic blocking action, CNS depression or paradoxical stimulation. These symptoms include nausea, vomiting, tachycardia, hyperthermia, drowsiness, impaired pupillary reflex, tremor, confusion, or hallucinations. This can lead to depression of consciousness, respiratory depression, seizures, decreased blood pressure, and arrhythmias. Deepening of coma and cardiopulmonary collapse may occur. It is necessary to monitor the condition of the respiratory tract, monitor respiration and circulation, with ECG monitoring, and ensure adequate oxygenation. Monitoring of heart function and blood pressure is necessary for 24 hours after the disappearance of symptoms. In case of mental status disorder, other preparations or alcohol intake should be excluded. If necessary, the patient should receive oxygen inhalation, naloxone, dextrose (glucose), and thiamine. If a vasopressor effect is needed, norepinephrine or metaraminol should be administered. Epinephrine should not be used. In case of ingestion of a large amount of the preparation, gastric lavage may be performed after endotracheal intubation. Activated charcoal may be used, but data on its effectiveness are insufficient. There is no specific antidote. Hemodialysis is ineffective. Literature data indicate that in severe, life-threatening, difficult-to-treat M-cholinergic blocking effects that are not controlled by other preparations, therapeutic doses of physostigmine may be used. Physostigmine should not be used solely to restore consciousness. If the patient has taken tricyclic antidepressants, the use of physostigmine may provoke a seizure and cause irreversible cardiac arrest. Physostigmine should also be avoided in patients with conduction disorders of the heart. Side effects Possible side effects are listed below by system organ class and frequency of occurrence: very common (≥1/10), common (≥1/100, <1/10), uncommon (≥1/1000, <1/100), rare (≥ 1/10000, <1/1000), very rare (<1/10000), frequency unknown (cannot be estimated from available data). Nervous system: Very common: drowsiness. Common: headache, slowed thinking. Uncommon: dizziness, insomnia, tremor. Rare: seizures, dyskinesia. Mental disorders: Uncommon: agitation, confusion. Rare: hallucinations, disorientation. Eye disorders: Rare: accommodation disorders, visual disturbances. Cardiac disorders: Rare: tachycardia. Frequency unknown: QT interval prolongation on electrocardiogram, ventricular tachycardia of the "pirouette" type. Respiratory, thoracic and mediastinal disorders: Very rare: bronchospasm. Gastrointestinal disorders: Common: dry mouth. Uncommon: nausea. Rare: vomiting, constipation. Hepatobiliary disorders: Rare: impaired liver function tests. Frequency unknown: hepatitis. General disorders: Common: weakness. Rare: hyperthermia, impaired self-feeling. Renal and urinary disorders: Rare: urinary retention. Skin and subcutaneous tissue disorders: Rare: itching, rash (erythematous, maculopapular), urticaria, dermatitis. Very rare: angioneurotic edema, increased sweating, fixed drug eruption, acute generalized exanthematous pustulosis, erythema multiforme, Stevens-Johnson syndrome. Immune system disorders: Rare: hypersensitivity. Very rare: anaphylactic shock. Vascular disorders: Rare: decreased blood pressure. The following side effects have been observed with the administration of cetirizine, the main metabolite of hydroxyzine: thrombocytopenia, aggression, depression, tics, dystonia, paresthesia, oculogyric crisis, diarrhea, dysuria, enuresis, asthenia, edema, weight gain, and may also occur during hydroxyzine administration. Interactions with other medicinal products The potential effect of hydroxyzine should be considered when used in combination with central nervous system depressants, such as narcotic analgesics, barbiturates, tranquilizers, hypnotics, and alcohol. In this case, their doses should be selected individually. Combination with monoamine oxidase (MAO) inhibitors and cholinoblockers should be avoided. The preparation counteracts the pressor effect of epinephrine and the anticonvulsant activity of phenytoin, and also counteracts the action of betahistine and cholinesterase inhibitors. It has been established that the use of cimetidine 600mg twice daily increases the concentration of hydroxyzine by 36% and reduces the maximum concentration of the metabolite cetirizine by 20%. The effects of atropine, belladonna alkaloids, cardiac glycosides, hypotensive agents, H2-histamine receptor blockers are not altered by hydroxyzine. Hydroxyzine is an inhibitor of the CYP D6 isoenzyme and at high doses can cause drug interactions with substrates of the CYP2D6 isoenzyme. Since hydroxyzine is metabolized in the liver, an increase in its concentration in the blood may be expected when used with inhibitors of hepatic microsomal enzymes. Since hydroxyzine is metabolized by alcohol dehydrogenase and the CYP3A4/5 isoenzyme, an increase in its plasma concentration may occur with preparations that inhibit the CYP3A4/5 isoenzyme (telithromycin, clarithromycin, delavirdine, stiripentol, ketoconazole, voriconazole, itraconazole, posaconazole, and some HIV protease inhibitors including atazanavir, indinavir, nelfinavir, ritonavir, saquinavir, lopinavir/ritonavir/saquinavir/ritonavir, and tipranavir/ritonavir). However, the inhibition of one metabolic pathway may be partially compensated by the action of another pathway. The use of hydroxyzine with preparations that can cause arrhythmias may increase the risk of QT interval prolongation and the possibility of ventricular tachycardia of the "pirouette" type. Pregnancy and lactation The preparation is contraindicated during pregnancy, childbirth, and lactation. Effect on ability to drive and operate machinery Hydroxyzine may impair concentration and psychomotor reaction ability. The intake of other sedatives may enhance this effect. Therefore, it is necessary to refrain from driving and other potentially dangerous activities that require increased concentration and rapid psychomotor reactions. Dosage form Film-coated tablets 25mg. 25 tablets in a PVC-aluminum foil blister. 1 blister with instructions for use in a cardboard box. Storage conditions In a dry place, at a temperature not exceeding 25°C. Keep out of reach of children. Shelf life 5 years. The preparation must not be used after the expiry date. Dispensing conditions Prescription only
- Active
- hydroxyzine
What is it?
ATARAX / ATARAX Composition Active ingredient: Hydroxyzine hydrochloride 25mg. Excipients: Lactose monohydrate 54.80mg, microcrystalline cellulose 28.00mg, magnesium stearate 1.50mg, colloidal silicon dioxide (anhydrous) 0.70mg. Coating: Opadry® Y-1-7000 3.30mg (titanium dioxide 0.21mg, hypromellose 2.06mg, macrogol 400 1.03mg). Description Film-coated, oblong, white tablets, with a cross score on both sides. Pharmacotherapeutic group: Anxiolytic agent (tranquilizer). ATC code: N05BB01. See blog: What is Atarax used for and what should we know about this preparation Pharmacological properties Pharmacodynamics Diphenylmethane derivative, suppresses the activity of certain subcortical zones. It has H1-antihistamine, bronchodilatory, and antiemetic effects, and moderately affects gastrointestinal secretion. Hydroxyzine significantly reduces itching in patients with urticaria, eczema, and dermatitis. In liver failure, after a single dose, the H1-antihistamine effect can be prolonged up to 96 hours. It has moderate anxiolytic activity and a sedative effect. Polysomnography in patients with insomnia and anxiety reveals an increase in sleep duration and a reduction in nocturnal arousal after single or repeated administration of hydroxyzine at a dose of 50mg. In patients with anxiety, a reduction in muscle tension is observed when the preparation is taken at a dose of 50mg 3 times a day. It does not cause psychological dependence or addiction. Long-term use does not lead to withdrawal syndrome or cognitive impairment. The H1-antihistamine effect occurs approximately 1 hour after taking the tablet. The sedative effect appears after 30-45 minutes. It has antispasmodic and sympatholytic effects, as well as moderate analgesic action. Pharmacokinetics Absorption Absorption is high after oral administration. Time to reach maximum concentration (Tmax) is 2 hours. After a single dose of 25mg in adults, Tmax is 30ng/ml, and 70ng/ml after taking 50mg of hydroxyzine. Bioavailability after oral administration is 80%. Distribution Hydroxyzine is more concentrated in tissues than in plasma. The distribution coefficient is 7-16 L/kg in adults. After oral administration, hydroxyzine penetrates the skin well, with its concentration in the skin greatly exceeding its concentration in the blood, both after single and multiple doses. Hydroxyzine crosses the blood-brain barrier and the placenta, and is more concentrated in fetal than in maternal tissues. Metabolism Hydroxyzine is metabolized in the liver. Cetirizine, the main metabolite (45%), is a peripheral H1-histamine receptor blocker. Metabolites are detected in lactate. Elimination Half-life (T1/2) in adults is 14 hours (range: 7-20 hours). The total clearance of hydroxyzine is 13 ml/min/kg. Only 0.8% of hydroxyzine is excreted unchanged by the kidneys. The main metabolite, cetirizine, is mainly excreted in the urine unchanged (25% of the administered dose). Pharmacokinetics in Special Patient Groups In elderly patients, T1/2 was 29 hours, and the volume of distribution was 22.5 L/kg. When administered to elderly patients, a reduction in the daily dose of hydroxyzine is recommended. In children, total clearance is 2.5 times higher than in adults. The half-life (T1/2) is shorter than in adults: 11 hours in children aged 14 years and 4 hours at 1 year of age. Dose adjustment should be made when used in children. In patients with liver failure, in patients with secondary liver dysfunction due to primary biliary cirrhosis, total clearance is approximately 66% of the value registered in healthy volunteers. In patients with liver disease, T1/2 increased up to 37 hours, and the concentration of metabolites in serum is higher than in young patients with normal liver function. In patients with liver failure, it is recommended to reduce the daily dose or duration of administration. In patients with renal failure, the pharmacokinetics of hydroxyzine were studied in 8 patients with severe renal failure (creatinine clearance 24 ± 7 ml/min). The duration of hydroxyzine exposure (AUC) did not change significantly, while the exposure to the carboxylated metabolite, cetirizine, increased. Hemodialysis is ineffective for the excretion of this metabolite. To prevent the accumulation of the metabolite cetirizine after repeated administration of hydroxyzine in patients with impaired renal function, it is recommended to reduce the daily dose of hydroxyzine. Indications • Symptomatic treatment of anxiety in adults • As a sedative agent during premedication • Symptomatic treatment of itching of allergic origin Contraindications • Hypersensitivity to any component of the preparation, to cetirizine and other piperazine derivatives, aminophylline or ethylenediamine • Porphyria • Children under 3 years of age • Pregnancy, childbirth or lactation period • Hereditary galactose intolerance, lactase deficiency or glucose-galactose malabsorption syndrome (as the tablets contain lactose). • Prolonged QT interval in history. Precautions In myasthenia gravis, with difficulty urinating due to benign prostatic hyperplasia, constipation, glaucoma, dementia, predisposition to seizures, predisposition to arrhythmias, including electrolyte imbalance (hypokalemia, hypomagnesemia) in patients with a history of heart disease or when using preparations that can cause arrhythmias. Method of administration and dosage Oral Children For symptomatic treatment of itching of allergic origin: In children aged 3 to 6 years: 1mg/kg per day - 2.5mg/kg/day in several doses. In children aged 6 years and older: 1mg/kg/day - 2.0mg/kg/day in several doses. For premedication - 1mg/kg at night before anesthesia. The number of tablets is determined by the doctor based on the child's weight, according to the recommended doses. Adults For symptomatic treatment of anxiety: Standard dose 50mg per day, divided into 3 doses (½ tablet (12.5mg) in the morning, ½ tablet (12.5mg) in the afternoon, and 1 tablet (25mg) at night). In severe cases, the dose can be increased up to 12 tablets (300mg) per day. For symptomatic treatment of itching of allergic origin: Initial dose 1 tablet (25mg) before bedtime, if necessary, the dose can be increased to 1 tablet (25mg) 3-4 times a day. For premedication in surgical practice: 2-8 tablets (50-200mg) at night before anesthesia. The maximum single dose for an adult should not exceed 8 tablets (200mg), the maximum daily dose should not exceed 12 tablets (300mg). Use in Special Patient Groups The dose is selected individually, depending on the patient's response to treatment, within the recommended dosage range. Use in the elderly In elderly patients, treatment is started with half the dose. For symptomatic treatment of anxiety: ½ tablet (12.5mg) in the morning and ½ tablet (12.5mg) in the evening. For symptomatic treatment of itching of allergic origin: Initial dose ½ tablet (12.5mg) before bedtime, if necessary, the dose can be increased to ½ tablet (12.5mg) 3-4 times a day. For premedication in surgical practice: 1-4 tablets (25-100mg) at night before anesthesia. Use in patients with renal failure and impaired liver function In patients with moderate and severe renal failure, as well as liver failure, dose reduction is necessary. In patients with liver failure, a 33% reduction in the daily dose is recommended. In patients with moderate renal failure, dose reduction is recommended due to decreased excretion of the main metabolite of hydroxyzine, cetirizine. It is necessary to reduce the dose of hydroxyzine or increase the interval between administrations in proportion to the decrease in creatinine clearance, for example: half the daily dose in moderate renal failure and a quarter in severe failure. Safety precautions When using preparations with M-cholinergic blocking properties and in combination with CNS depressants, it is necessary to reduce the dose of hydroxyzine. In case of renal and/or liver failure, doses should be reduced. If allergy tests and methacholine tests are necessary, the administration of the preparation should be discontinued 5 days before the examination to avoid distorted results. Alcohol consumption should be avoided during hydroxyzine treatment. Overdose Symptoms observed after significant overdose of the preparation are related to strong M-cholinergic blocking action, CNS depression or paradoxical stimulation. These symptoms include nausea, vomiting, tachycardia, hyperthermia, drowsiness, impaired pupillary reflex, tremor, confusion, or hallucinations. This can lead to depression of consciousness, respiratory depression, seizures, decreased blood pressure, and arrhythmias. Deepening of coma and cardiopulmonary collapse may occur. It is necessary to monitor the condition of the respiratory tract, monitor respiration and circulation, with ECG monitoring, and ensure adequate oxygenation. Monitoring of heart function and blood pressure is necessary for 24 hours after the disappearance of symptoms. In case of mental status disorder, other preparations or alcohol intake should be excluded. If necessary, the patient should receive oxygen inhalation, naloxone, dextrose (glucose), and thiamine. If a vasopressor effect is needed, norepinephrine or metaraminol should be administered. Epinephrine should not be used. In case of ingestion of a large amount of the preparation, gastric lavage may be performed after endotracheal intubation. Activated charcoal may be used, but data on its effectiveness are insufficient. There is no specific antidote. Hemodialysis is ineffective. Literature data indicate that in severe, life-threatening, difficult-to-treat M-cholinergic blocking effects that are not controlled by other preparations, therapeutic doses of physostigmine may be used. Physostigmine should not be used solely to restore consciousness. If the patient has taken tricyclic antidepressants, the use of physostigmine may provoke a seizure and cause irreversible cardiac arrest. Physostigmine should also be avoided in patients with conduction disorders of the heart. Side effects Possible side effects are listed below by system organ class and frequency of occurrence: very common (≥1/10), common (≥1/100, <1/10), uncommon (≥1/1000, <1/100), rare (≥ 1/10000, <1/1000), very rare (<1/10000), frequency unknown (cannot be estimated from available data). Nervous system: Very common: drowsiness. Common: headache, slowed thinking. Uncommon: dizziness, insomnia, tremor. Rare: seizures, dyskinesia. Mental disorders: Uncommon: agitation, confusion. Rare: hallucinations, disorientation. Eye disorders: Rare: accommodation disorders, visual disturbances. Cardiac disorders: Rare: tachycardia. Frequency unknown: QT interval prolongation on electrocardiogram, ventricular tachycardia of the "pirouette" type. Respiratory, thoracic and mediastinal disorders: Very rare: bronchospasm. Gastrointestinal disorders: Common: dry mouth. Uncommon: nausea. Rare: vomiting, constipation. Hepatobiliary disorders: Rare: impaired liver function tests. Frequency unknown: hepatitis. General disorders: Common: weakness. Rare: hyperthermia, impaired self-feeling. Renal and urinary disorders: Rare: urinary retention. Skin and subcutaneous tissue disorders: Rare: itching, rash (erythematous, maculopapular), urticaria, dermatitis. Very rare: angioneurotic edema, increased sweating, fixed drug eruption, acute generalized exanthematous pustulosis, erythema multiforme, Stevens-Johnson syndrome. Immune system disorders: Rare: hypersensitivity. Very rare: anaphylactic shock. Vascular disorders: Rare: decreased blood pressure. The following side effects have been observed with the administration of cetirizine, the main metabolite of hydroxyzine: thrombocytopenia, aggression, depression, tics, dystonia, paresthesia, oculogyric crisis, diarrhea, dysuria, enuresis, asthenia, edema, weight gain, and may also occur during hydroxyzine administration. Interactions with other medicinal products The potential effect of hydroxyzine should be considered when used in combination with central nervous system depressants, such as narcotic analgesics, barbiturates, tranquilizers, hypnotics, and alcohol. In this case, their doses should be selected individually. Combination with monoamine oxidase (MAO) inhibitors and cholinoblockers should be avoided. The preparation counteracts the pressor effect of epinephrine and the anticonvulsant activity of phenytoin, and also counteracts the action of betahistine and cholinesterase inhibitors. It has been established that the use of cimetidine 600mg twice daily increases the concentration of hydroxyzine by 36% and reduces the maximum concentration of the metabolite cetirizine by 20%. The effects of atropine, belladonna alkaloids, cardiac glycosides, hypotensive agents, H2-histamine receptor blockers are not altered by hydroxyzine. Hydroxyzine is an inhibitor of the CYP D6 isoenzyme and at high doses can cause drug interactions with substrates of the CYP2D6 isoenzyme. Since hydroxyzine is metabolized in the liver, an increase in its concentration in the blood may be expected when used with inhibitors of hepatic microsomal enzymes. Since hydroxyzine is metabolized by alcohol dehydrogenase and the CYP3A4/5 isoenzyme, an increase in its plasma concentration may occur with preparations that inhibit the CYP3A4/5 isoenzyme (telithromycin, clarithromycin, delavirdine, stiripentol, ketoconazole, voriconazole, itraconazole, posaconazole, and some HIV protease inhibitors including atazanavir, indinavir, nelfinavir, ritonavir, saquinavir, lopinavir/ritonavir/saquinavir/ritonavir, and tipranavir/ritonavir). However, the inhibition of one metabolic pathway may be partially compensated by the action of another pathway. The use of hydroxyzine with preparations that can cause arrhythmias may increase the risk of QT interval prolongation and the possibility of ventricular tachycardia of the "pirouette" type. Pregnancy and lactation The preparation is contraindicated during pregnancy, childbirth, and lactation. Effect on ability to drive and operate machinery Hydroxyzine may impair concentration and psychomotor reaction ability. The intake of other sedatives may enhance this effect. Therefore, it is necessary to refrain from driving and other potentially dangerous activities that require increased concentration and rapid psychomotor reactions. Dosage form Film-coated tablets 25mg. 25 tablets in a PVC-aluminum foil blister. 1 blister with instructions for use in a cardboard box. Storage conditions In a dry place, at a temperature not exceeding 25°C. Keep out of reach of children. Shelf life 5 years. The preparation must not be used after the expiry date. Dispensing conditions Prescription only