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Tsetrilev
Tsetrilev is an antihistamine systemic drug, a substance derivative piperazine.
Pharmacodynamics
Levocetirizine is an active R-enantiomer of cetirizine with stable properties. An integral element of the group of competitive histamine antagonists. Its medicinal properties are determined by blocking the endings of histamine H1. The affinity for these elements in levocetirizine is twice that of cetirizine.
It affects the histamine-dependent stage of development of allergy manifestations, reduces vascular permeability, eosinophil migration activity, and also limits the release of inflammatory conductors. Prevents the appearance of an allergic response, and, together with this, facilitates the flow of already existing symptoms. The component also has anti-inflammatory, anti-allergenic and anti-exsudative properties, with almost no antiserotonin and holinolytic effect.
At reception in medicinal doses practically does not possess a calming effect.
Pharmacokinetics
The pharmacokinetics of levocetirizine is linear and practically does not differ from the properties of cetirizine.
When taken orally, the medicine is absorbed intensively and quickly. At the same time, the degree of absorption does not change with the use of food and the size of the dose taken, although a decrease in the peak concentration and an extension of the time of its attainment are observed. The level of bioavailability is 100%.
In 5% of patients treated, the drug begins 12 minutes after a single use, and the rest 95% after 0.5-1 hour. Plasma peak level is observed after 50 minutes after oral single dose of drug, and its duration is 2 days. The peak value is 270 ng / ml for a single dose, as well as 308 ng / ml for 5 mg of the drug again.
There is no information about the distribution of the drug inside the tissues and its passage through the BBB. Tests have shown that the highest concentration is observed in the kidneys with the liver, and the lowest - inside the tissues of the central nervous system. The distribution volume is 0.4 l / kg. The synthesis of a substance with a plasma protein is 90%.
Inside the body, approximately 14% of levocetirizine is metabolized. During this process, there is a connection with taurine, oxidation, also N- and O-dealkylation. The latter are carried out with the help of the hemoprotein CYP 3A4, while the oxidative processes are assisted by numerous or unknown isoforms of the CYP element.
Levocetirizine has no effect on the activity of hemoprotein isoenzymes 1A2 with 2C9, as well as 2C19 and 2D6, together with 2E1 and 3A4 at rates that exceed the maximum level by oral intake of 5 mg of the drug at times. Since the metabolism is quite low, and the ability to inhibit this process is absent, the likelihood of interaction of levocetirizine and other medicinal components is extremely small.
Excretion of the substance is mainly performed by filtration of glomeruli and active secretion of the tubules. The half-life from plasma (adults) is 7.9 + 1.9 hours. This segment is shorter in children. The total clearance rate (adults) is 0.63 ml / minute / kg. Excretion of the active ingredient and decay products mainly occurs in the urine (the average is 85.4% of the dose used). Only 12.9% of the substance is excreted with feces.
The apparent coefficient of purification of levocetirizine in the body is in correlation with the KK index. Because of this, people with severe or moderate degree of disorders in the work of the kidneys need to select the intervals between the use of levocetirizine, given the QC values. In the presence of anuria in the final stage of the terminal stage of renal pathology, the overall level of clearance in such people, in comparison with similar indicators in persons without similar disorders, is reduced by approximately 80%.
The amount of active substance released during hemodialysis (the standard procedure lasting 4 hours) is equal to <10%.
Contraindications
The main contraindications:
- intolerance of levocetirizine or other elements of the drug, as well as various derivatives of piperazine;
- chronic form of kidney failure in severe degree (CC level is <10 ml / minute);
- prescribe levocetirizine to newborns, and children up to six months are prohibited, since information on the use of drugs at this age is very limited;
- tablets should not be taken to children younger than 6 years of age.
Side effects of the tsetrileva
The constituent elements of methylparaben syrup with propyl parahydroxybenzoate can cause the following side effects (may have delayed reaction):
- manifestations from the NA: a feeling of weakness, drowsiness, severe fatigue, the appearance of headaches, fainting, seizures, tremors, paresthesias and dizziness, as well as the development of dysgeusia or asthenia;
- mental disorders: a sense of excitement, aggression, the appearance of hallucinations, thoughts about suicide, depression, insomnia and other sleep disorders;
- heart reactions: development of tachycardia or increased heart rate;
- visual organs: blurred vision and other disorders;
- auditory disorders: development of the vertigo;
- bile duct and liver: development of hepatitis;
- urinary organs and kidneys: retention of urination and the appearance of dysuria;
- immunity reactions: manifestations of hypersensitivity, among which anaphylaxis;
- organs of the respiratory system, mediastinum and sternum: the emergence of dyspnea;
- reactions of the gastrointestinal tract: the appearance of constipation, nausea, diarrhea, vomiting, abdominal pains and dryness of the mucous membranes of the mouth;
- subcutaneous layers and skin: the appearance of a persistent drug-induced rash, other rashes and itching, and in addition the development of urticaria or Quincke edema;
- muscular structure and bones: the onset of myalgia;
- indications of laboratory tests: weight gain, change in normal parameters of hepatic function;
- disorders of metabolic processes: increased appetite;
- systemic disorders: the appearance of edemas.
Dosing and administration
Syrup should be taken orally (children from six months and adults) regardless of eating. Such sizes are recommended:
- Infants 0.5-1 year - once a day for 1.25 mg (or 2.5 ml);
- age 1-2 years - twice a day for 1.25 mg (daily dose will be 2.5 mg);
- age 2-6 years - twice a day to take 1.25 mg (or 2.5 ml) of the drug;
- age 6-12 years - for a day of 5 mg (or 10 ml) of drugs;
- adolescents from 12 years, and in addition adults - once a day for 5 mg (or 10 ml) of syrup.
People who have disorders in the work of the kidneys need to calculate the dosages in accordance with the QC indices. The calculation is as follows:
- with normal kidney function (CC level ≥80 ml / minute) - 5 mg once a day;
- in disorders of mild severity (KK value of 50-79 ml / minute) - a single dose of 5 mg LS;
- disorders of moderate severity (level of CK 30-49 ml / minute) - take 5 mg once every other day;
- severe disorder (CC level <30 ml / minute) - taking 5 mg of syrup once every 3 days;
- the final stage of renal pathology (level of CC <10 ml / minute) and persons on dialysis - the reception of drugs is prohibited.
The duration of syrup intake for people with a periodic form of allergic rhinitis (signs of the disease appear during <4 days per week or less than 1 month) is determined taking into account the history and course of the pathology. Stop the therapy can be on the disappearance of symptoms and resume, if the allergy begins again.
With a stable form of an allergic rhinitis (signs of the disease appear> 4 days a week or in a period longer than the 1st month) during constant contact with allergens - permanent treatment is possible.
To eliminate chronic pathologies (hives or allergic rhinitis), a course up to 1 year may be needed (this information was obtained through tests using a racemate).
Tablets should be consumed orally, washed down with water and not chewed. In the case of fasting, the onset of drug exposure occurs more quickly.
The daily dose for children from 6 years and adults - 5 mg once a day (1 tablet). In the treatment of pollinosis, the course lasts an average of 1-6 weeks. To eliminate allergic diseases of a chronic type, a course up to 1 year may be needed.
Overdose
The appearance of an overdose is a feeling of drowsiness, but in children this symptom is preceded by increased irritability and agitation.
Levocetirizine does not have a specific antidote. In the development of violations it is necessary to provide assistance to the victim, aimed at maintaining the condition and eliminating symptoms. A variant with gastric lavage is possible, if the medicine was taken recently. The procedure of hemodialysis will not work.
Interactions with other drugs
Tests for the interaction of levocetirizine were not performed.
Testing the same interactions of cetirizine (in combination with the racemate) demonstrated that the combination with cimetidine, antipyrine, and in addition ketoconazole and pseudoephedrine, as well as substances azithromycin, erythromycin and glipizide or diazepam does not cause drug-related side effects.
When combined with theophylline (daily dose of 400 mg), the overall clearance of levocetirizine is reduced (by 16%), and the theophylline properties remain unchanged.
Testing of multiple-dose ritonavir (twice daily for 600 mg) with cetirizine (10 mg per day) demonstrated that the exposure index of the latter increased by about 40%, while the volume of ritonavir distribution slightly changed (-11%) before combination with cetirizine.
Food does not affect the degree of absorption of the drug, but it lowers its speed.
Medical expert editor
Portnov Alexey Alexandrovich
Education: Kiev National Medical University. A.A. Bogomolets, Specialty - "General Medicine"
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Attention!
To simplify the perception of information, this instruction for use of the drug "Tsetrilev" translated and presented in a special form on the basis of the official instructions for medical use of the drug. Before use read the annotation that came directly to medicines.
Description provided for informational purposes and is not a guide to self-healing. The need for this drug, the purpose of the treatment regimen, methods and dose of the drug is determined solely by the attending physician. Self-medication is dangerous for your health.