Zyrtec 10 mg Tablets

Brand name

The trade name of the drug is Zyrtec. Under this name it is registered and available in pharmacies for medical use.

International Nonproprietary Name (INN)

The international nonproprietary name is cetirizine. This name denotes the active active ingredient and is used in pharmacology worldwide.

Form of release

Zyrtec is available in several forms to meet the needs of different age groups: film-coated tablets, 10 mg in blisters of 7, 10 or 20 pieces, drops for oral administration with a concentration of 10 mg / ml in bottles of 10 ml or 20 ml with a dropper; syrup with a concentration of 5 mg / 5 ml in bottles of 100 ml with a measuring spoon. Tablets are intended for adults and older children, while drops and syrup are convenient for younger patients.

Composition

Acting substance

The active ingredient is cetirizine hydrochloride. One tablet contains 10 mg of cetirizine hydrochloride, 1 ml of drops - 10 mg, and 5 ml of syrup - 5 mg.

Auxiliary Components

Tablets include lactose monohydrate, microcrystalline cellulose, crospovidone, magnesium stearate, and a coating of hypromellose, titanium dioxide, and macrogol. The drops contain glycerin, propylene glycol, sodium acetate, acetic acid and purified water. The syrup consists of sorbitol, glycerin, sodium benzoate, banana flavoring and water.

Pharmacologic Properties

Pharmacodynamics

Cetirizine, the active ingredient of Zyrtec, is a selective second-generation H1-histamine receptor antagonist. Its mechanism of action is to prevent the binding of histamine to receptors on the surface of cells, which blocks the development of allergic reactions such as swelling, hyperemia and mucus secretion. The drug effectively reduces vascular permeability, reduces the migration of eosinophils into the foci of inflammation and inhibits the release of allergy mediators such as leukotrienes and prostaglandins. This provides a pronounced anti-inflammatory and anti-allergic action.

In contrast to first-generation antihistamines, cetirizine has a low ability to penetrate the blood-brain barrier, which minimizes the sedative effect, although some patients may still experience mild sedation. The therapeutic effect begins 20-60 minutes after administration and lasts up to 24 hours, which allows using the drug once a day. Zyrtec also demonstrates the ability to reduce itching in skin allergic reactions, which makes it particularly useful in chronic urticaria.

Pharmacokinetics

Absorption

Cetirizine is rapidly absorbed from the gastrointestinal tract after oral administration. Maximum concentration in blood plasma is reached in 0.5-1 hour, and bioavailability is about 70%. Food intake does not significantly affect the total absorption, although it may slightly slow the rate of absorption.

Distribution

The drug binds to blood plasma proteins, mainly albumin, by 93%. The volume of distribution is about 0.5 L/kg, indicating limited tissue penetration and minimal accumulation in the central nervous system. This property contributes to the low incidence of CNS-related side effects.

Metabolism

Cetirizine undergoes minimal metabolism in the liver. The bulk of the substance is excreted unchanged, which distinguishes it from many other antihistamines. A small proportion is metabolized by O-dealkylation to form inactive metabolites, which does not affect the therapeutic effect.

Excretion

The half-life of cetirizine is 7-11 hours in adults, in children it is shorter (about 5-7 hours), and in elderly patients it may increase up to 12-14 hours. The drug is excreted mainly through the kidneys (about 70% in unchanged form), the rest is excreted through the intestine. Complete excretion from the body occurs within 3-4 days.

Indications for Use

Zyrtec is prescribed for the treatment of the following conditions:

• Seasonal allergic rhinitis caused by plant pollen (pollinosis);
• Year-round allergic rhinitis associated with household allergens (dust, animal hair, mold);
• Chronic idiopathic urticaria with itching and skin rashes;
• Allergic conjunctivitis with symptoms of itching and lacrimation (as part of complex therapy);
• Dermatoses of allergic nature accompanied by itching and skin irritation.

The drug is effective for rapid relief of acute symptoms and long-term control of allergic manifestations.

Contraindications

The use of Zyrtec is prohibited in the following cases:

• Individual intolerance to cetirizine or auxiliary components;
• Severe renal insufficiency (creatinine clearance less than 10 ml/min);
• Hereditary lactose intolerance or lactase deficiency (for tablets);
• Children less than 6 months of age (for drops) or less than 6 years of age (for tablets);
• Pregnancy and breastfeeding period.

With caution, the drug is prescribed in epilepsy, chronic hepatic insufficiency or tendency to urinary retention.

Method of Administration and Dosage

How to take

Zyrtec tablets are taken orally, drinking a small amount of water (50-100 ml). Drops are diluted in a small volume of water (5-10 ml) before taking, and syrup is measured with a measuring spoon and taken orally. Food intake does not affect the effectiveness, so the drug can be used at any time of day, preferably at the same time.

Dosages for adults and children

Adults and children over 12 years of age

The standard dose is 10 mg (1 tablet, 10 drops or 10 ml of syrup) once a day.

Children 6 to 12 years of age

Recommended is 5 mg (5 drops, 5 ml syrup or half a tablet) twice daily or 10 mg once.

Children 2 to 6 years of age

Dosage is 2.5 mg (2.5 mL of syrup or 5 drops) twice daily or 5 mg once.

Children 6 months to 2 years of age

Prescribe 2.5 mg (5 drops) once daily.

Dose adjustment for certain conditions

In moderate renal insufficiency (creatinine clearance 30-49 ml/min) the dose is reduced to 5 mg per day. In severe renal failure, the drug is contraindicated. Hepatic insufficiency usually does not require dose adjustment if renal function is preserved.

Side Effects

Zyrtec is well tolerated, but the following reactions may occur:

• Nervous system: drowsiness, fatigue, headache, dizziness;
• Gastrointestinal tract: dry mouth, nausea, abdominal discomfort;
• Respiratory system: pharyngitis, dry nose;
• Allergic reactions: rash, itching, rarely - angioedema;
• Other: weight gain, irritability (especially in children).

The side effects are usually mild and pass independently.

Overdose

Symptoms of overdose

Doses above 50 mg may cause drowsiness, confusion, tremor, tachycardia, urinary retention.

First aid measures

In case of overdose, stop taking the drug and consult a doctor. Prior to medical attention, the stomach can be washed (if less than an hour has passed) and activated charcoal can be given.

Drug Interactions

Influence on the effects of other drugs

Cetirizine has no significant effect on the metabolism of other drugs. Co-administration with theophylline may slightly slow the excretion of cetirizine, but no dose adjustment is required.

Compatibility with alcohol and food

Alcohol may increase the mild sedative effect of Zyrtec in sensitive patients. Food does not affect pharmacokinetics.

Special Precautions

Use in pregnancy and breastfeeding

Zyrtec is not recommended in pregnancy due to insufficient data. Cetirizine penetrates into breast milk, so breastfeeding should be discontinued for the duration of treatment.

Effects on driving and mechanisms

The drug may cause drowsiness in some patients, so caution is required when driving or operating machinery.

Particularities of use in elderly people and children

In the elderly, the dose is adjusted in case of impaired renal function. In children, the drug is safe if the age dosage is observed.