Cetirizine

Cetirizine is a drug that blocks the H1 histamine receptors. It is effective at the early stage of allergic manifestations and also reduces the amount of released allergy conductors. The drug is used to eliminate different types of allergies.

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Indications Cetirizine

It is used to eliminate the following types of pathologies:

• hay fever;
• allergic rhinitis;
• dermatitis;
• conjunctivitis;
• angioedema and urticaria.

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Release form

The product is released in tablets, on a blister of 10 pieces. Inside the package there are 1-2 blister plates.

Cetirizine hexal

Cetirizine hexal is an antihistamine for systemic use. It is available as an oral solution.

Cetirizine-astrapharm

Cetirizine-astrapharm is a general-purpose antihistamine, a derivative of piperazine.

Cetirizine-Norton

Cetirizine-Norton is used to relieve symptoms of seasonal allergic rhinitis or its chronic form, as well as chronic idiopathic urticaria.

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Pharmacodynamics

Cetirizine is a breakdown product of hydroxyzine in the human body. It is a potent selective antagonist of peripheral H1 terminals. During synthesis with receptors in vitro studies, no affinity for other terminals that differ from H1 receptors arose.

In addition to the antagonist effect on H1 receptors, the substance has antiallergic properties. In the case of the drug administration in a dose of 10 mg once/twice a day, it slows down the last stage of the involvement of inflammatory cells (especially eosinophils) in the process of spreading inside the conjunctiva and skin of people who have been administered an antigen. At a daily dose of 30 mg, the drug slows the entry of eosinophils together with bronchoalveolar fluid during the late stage of bronchial narrowing, which occurs when an allergen is inhaled by a person suffering from bronchial asthma.

Cetirizine also slows down the late stage of the inflammatory reaction caused by intradermal injection of kallikrein in people with chronic urticaria. At the same time, it reduces the strength of molecular adhesion (elements of ICAM-1, as well as VCAM-1, which act as markers of allergy-induced inflammation).

There is information that the drug in dosages of 5 and 10 mg can slow down the appearance of redness and blisters that occur due to excessively high histamine levels in the skin. With a single use of 10 mg of the drug, the effect begins after 20 minutes / 1 hour. The effect of its use lasts at least 24 hours with a single dose.

There is information that children aged 5-12 years do not show tolerance to the antihistamine properties of Cetirizine (suppression of the development of redness and blisters). After completion of repeated treatment with cetirizine, the normal skin reaction to histamine is restored in about 3 days.

In people with allergic rhinitis and concomitant bronchial asthma (mild or moderate severity), taking the drug in a dose of 10 mg once a day helped improve the condition in the presence of signs of rhinitis, without affecting the functioning of the lungs. These data confirm the safety of using the drug in bronchial asthma of moderate or mild severity.

There is evidence that the use of large daily doses of cetirizine (60 mg) did not induce significant prolongation of the QT interval.

Taking the medicine in the recommended dose improves the health of people with seasonal or year-round allergic rhinitis.

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Pharmacokinetics

The peak equilibrium level of the substance in plasma is almost 300 ng/ml, and it takes about 1±0.5 hours to achieve this indicator. There was no accumulation of the substance in the case of taking the drug in the amount of 10 mg over a period of 10 days.

The volume of absorption of the substance does not decrease in the case of combined intake with food, but its rate decreases. The volumes of bioavailability indicators are similar when using the substance in the form of capsules, solution or tablets. The apparent distribution volume is 0.5 l / kg. Synthesis of the substance with plasma proteins is 93 ± 0.3%. At the same time, cetirizine does not affect the processes of synthesis of warfarin with blood protein.

The substance does not undergo extensive first-pass metabolism. About 2/3 of the dose is excreted unchanged in the urine. The terminal half-life is approximately 10 hours. Cetirizine has linear pharmacokinetics when administered in doses of 5-60 mg.

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Dosing and administration

Teenagers aged 12 and over, as well as adults, should take the medicine in the amount of 10 mg once in the evening with dinner or twice a day (morning and evening) at 5 mg. For children aged 2-6 years, the dose is 5 mg (or 10 drops) once a day or 2.5 mg (or 5 drops) twice a day (morning and evening).

People with kidney failure require half the standard dose.

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Use Cetirizine during pregnancy

Contraindicated during pregnancy.

Since Cetirizine passes into breast milk, it should not be administered during lactation.

Contraindications

Among the contraindications:

• intolerance to cetirizine, hydroxyzine, and other components of the drug;
• decreased renal function indicators (creatinine clearance level within 30-49 ml/minute);
• chronic renal failure;
• children under 6 years of age.

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Side effects Cetirizine

Cetirizine is often well tolerated. Side effects are rare and short-lived. The main manifestations are:

• reactions of the digestive system: dyspeptic symptoms and dryness of the oral mucosa;
• manifestations from the nervous system: headaches, migraines, dizziness, feelings of excitement, drowsiness or fatigue;
• allergic reactions: skin rash, Quincke's edema, urticaria and itching.

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Overdose

After a single use of the drug in the amount of 50 mg, the following signs of overdose develop: a feeling of drowsiness, severe irritability or anxiety, as well as constipation, dry mouth mucous membranes and delayed urination.

Gastric lavage and symptomatic treatment will be required to eliminate the disorder. There is no specific antidote. Hemodialysis will be ineffective.

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Interactions with other drugs

Combined use with theophylline (at a daily dose of 400 mg) causes a decrease in the level of the total clearance coefficient of cetirizine (while the properties of theophylline do not change).

Myelotoxic drugs increase the hematotoxic effect of the drug.

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Storage conditions

Cetirizine should be kept in a place protected from sunlight and moisture, out of reach of children. Temperature conditions – no more than 25ºС.

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Shelf life

Cetirizine is suitable for use for a period of 2 years from the date of manufacture of the tablets.

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