Zoster

Zestra is a system antihistamine drug, the active ingredient of which is cetirizine.

Indications Zoster

It is shown in the treatment of the common cold, as well as allergic conjunctivitis (regular or seasonal), and in addition to the recurrent form of urticaria (chronic stage).

Release form

Available in tablet form, 10 pieces per blister. In one package contains 1 blister plate.

Pharmacodynamics

Zestra is a combined medicine, its properties are determined by the action of the components that make up its composition.

Cetirizine hydrochloride is an antihistamine substance of the second generation, an selective receptor blocker (H1); has a prolonged action. Also has weak anticholinergic properties, has no interaction with dopamine and serotonergic receptors, as well as H2 and α-adrenoreceptors.

The pronounced synthesis with a plasma protein, as well as the polarity of cetirizine, are the reason that it passes poorly through the BBB and has almost no effect on the CNS, which is what distinguishes this drug from the 1st generation antihistamine drugs. Such properties are mainly the result of its lipophilicity.

The active component acts on the early histamine-dependent stage of the development of allergic manifestations, and in addition inhibits the release of histamine from basophilic leukocytes to fat cells and reduces the frequency of movement of inflammatory cells that are participants in allergic responses (slows the movement of eosinophils and inhibits the release of mast cells from inflammatory conductors ). It also weakens the effect of the conductors of the allergic response (histamine and PG D2), and at the same time inhibits the movement of eosinophils in people who have atopic reactions. In addition, it reduces histamine-induced bronchoconstriction (in the presence of bronchial asthma) and provokes a prolonged selective effect on the receptors (H1).

The drug begins 2 hours after use and lasts for 24 hours.

Pseudoephedrine hydrochloride is a β-agonist with vasoconstrictor properties. It reduces the swelling of the mucosa of the upper respiratory tract (especially in the nasal adnexal and nasopharynx) during symptomatic therapy of infectious-inflammatory and allergic pathologies in this area.

[1]

Pharmacokinetics

The active ingredient is rapidly absorbed from the digestive tract. Peak serum concentration at equilibrium is 300 ng / ml (observed after 0.5-1 hour after use). When applied on an empty stomach, approximately 70% of the substance is absorbed. Eating does not have an effect on suction volumes, but slows down the speed of this process. Peak medicinal effect begins after 4-8 hours and lasts about 24 hours. Approximately 93% of the active component is synthesized with a plasma protein.

The distribution volume is 0.56-0.8 l / kg (adults), as well as 0.7 l / kg (children). The substance is partially metabolized. With an everyday drug intake of 10 mg for 10 days cumulation of cetirizine was not detected.

Approximately 60% of the dosage is excreted in urine over the next 24 hours, and then in the next 4 days, about 10% of the substance is released in the same way. In this case, children within 24 hours are excreted only 40% of the drug. For 5 days about 10% of the dosage (including under the guise of a decay product) is excreted with feces.

The half-life of the active ingredient is 7.4 hours. In the case of kidney failure in the patient, elimination will occur more slowly. With weak disorders of kidney function, this period sometimes increases until 19-21 hours.

The coefficient of cleansing of the substance in the kidneys is 70 ml / minute (with healthy kidney function), if there are mild violations of the function, this figure is 7 ml / min; with a moderate expression - 1.5 ml / minute. To eliminate the component is not suitable method of hemodialysis.

Pseudoephedrine hydrochloride is absorbed fairly quickly through the digestive tract, starting to act half an hour after the drug is consumed. In general, its action lasts 4 hours.

Partial metabolism of pseudoephedrine is carried out through the liver with the help of N-demethylation - it is converted into the active product of the decomposition of norpseudoephedrine.

The pseudoephedrine component together with its decay products is excreted together with the urine; about 55-75% of a single dose is displayed unchanged. The rate of excretion of a substance increases in the case of urine oxidation, and when it is alkalized, it decreases.

The half-life is 7 hours. A small part of the pseudoephedrine passes into the breast milk (within a period of 24 hours, about 0.5-0.7% of the unit dosage of the drug consumed by the mother falls into the milk).

[2], [3],

Dosing and administration

The medicine is used inside. For children over 12 years of age and adults, the dosage is 1 tablet per day, which should be taken with water. The duration of the course is determined by the treating doctor - it depends on the severity of the pathology, as well as on the patient's condition.

[5], [6]

Use Zoster during pregnancy

The medicine is forbidden to be given to pregnant women, and also during lactation.

Contraindications

Among the contraindications:

• intolerance of the constituent components of the drug;
• marked disorders of renal function (creatinine clearance less than 10 10 ml / minute);
• insomnia;
• uncontrolled increase in blood pressure, as well as tachycardia;
• obstructive form of HCM;
• IHD;
• presence in the patient of pheochromocytoma, hyperthyroidism or diabetes mellitus;
• severe forms of hepatic pathologies;
• ventricular fibrillation;
• use of MAO inhibitors in the previous period before using drugs for 2 weeks;
• age less than 12 years.

Side effects Zoster

The use of drugs can cause such adverse reactions:

• organs of the digestive system: weight gain, dyspepsia, eating disorder and its delay; anorexia, stomatitis, gastritis, diabetes mellitus, and liver function disorder (an increase in the activity of liver enzymes, Y-glutamyltransferase, as well as alkaline phosphatase, and also an increase in the activity of the bilirubin component). In addition, there are single appear - dryness in the mouth, thirst, swelling and discoloration of the tongue, nausea, bloating, abdominal pain, and vomiting;
• organs of the National Assembly: a feeling of drowsiness and dizziness; occasionally develop headaches, tremor with migraine, hyper- and hypersthesia with paresthesias, seizures and fainting, and in addition excessive aggressiveness, asthenia, confusion, a feeling of excitement or malaise, a state of depression, severe fatigue, insomnia and the appearance of hallucinations;
• organs of the cardiovascular system: dystonia appears alone, tachycardia and the blood pressure level increases;
• organs of the hematopoietic system: development of thrombocytopenia;
• visual organs: blurred vision, as well as a disorder of accommodation and involuntary movements of the eyes;
• respiratory organs: nosebleeds, runny nose with cough, spasms of the bronchi, development of pharyngitis, inflammation of the lungs, bronchitis and dysphonia;
• organs of the immune system: rashes and itching, as well as urticaria; edema, allergic manifestations, anaphylaxis and Quincke edema are observed singly;
• bone structure and musculature: arthritis, pain in muscles and joints, muscle weakness and dyskinesia;
• organs of the urinary system: dysuria, problems with urination, and also enuresis.

Side effects provoked by pseudoephedrine hydrochloride:

• organs of the cardiovascular system: development of brady, steno- or tachycardia, palpitations, increase / decrease in blood pressure, the appearance of swelling, heart failure, arrhythmia, and chest pain;
• organs of the National Assembly: dizziness and headaches, anxiety, nervousness, agitation, development of tremors and emotional lability. In addition to this disorder of thought or attention, as well as psychoneurological disorders (memory problems, disorientation, development of psychomotor agitation, panic or aggression, paranoia, schizophrenia disorders, and the appearance of hallucinations (all due to the central effect of pseudoephedrine), along with this - a state of insomnia, sleep disorders, the appearance of convulsions and twitching of muscles, hyperkinesis, a sense of euphoria or amnesia, and in addition a state of depression);
• organs of the digestive system: increased appetite, constipation, increased salivation, nausea, bloating, abdominal pain, vomiting, diabetes and liver function disorder;
• organs of the genitourinary system: pain or difficulty with urination (in the case of prostate hyperplasia), as well as its delay, the development of cystitis, polyuria, pyelitis, hematuria or dysuria. In addition, the appearance of vaginitis or dysmenorrhea, as well as a decrease in libido;
• allergic manifestations: development of erythema polyforma;
• sensory organs: eye pain or bleeding, vision disorders, tinnitus or glaucoma, development of deafness, ptosis and xerophthalmia;
• Other: the appearance of chills, feelings of weakness, the development of fever, hypokalemia or lymphadenopathy, as well as increased sweating. These manifestations disappeared after drug withdrawal.

[4]

Overdose

Manifestations of an overdose, as a rule, are related to the effect on the central nervous system or due to the anticholinergic properties of drugs. Among them: a feeling of embarrassment, the appearance of dizziness, psychoemotional agitation, a feeling of irritation, nervousness, and in addition, severe fatigue, drowsiness or insomnia, severe headaches and a state of stupor. In addition, there are delays in urination, impaired circulation, sweating. Along with this, convulsions, tremors, tachycardia and trembling of the limbs may occur. Lack of appetite, vomiting, dry mouth, nausea and diarrhea, increased blood pressure, itching with rashes and mydriasis are also possible.

To get rid of these signs, the patient needs to rinse the stomach and continue taking enterosorbents.

In addition, to eliminate the above-described manifestations, methods are used to correct the functioning of the cardiovascular system, and also to support the external respiratory process. If necessary, anticonvulsants are used and bladder catheterization is performed. An effective option for accelerating the elimination of pseudoephedrine is dialysis or urine acidification. There is no specific antidote.

[7]

Interactions with other drugs

The active component of Zestra does not interact with other drugs (such as cimetidine, pseudoephedrine, and erythromycin with ketoconazole and diazepam with azithromycin). In case of consumption with a large amount of alcohol (the blood concentration is greater than 0.8 ‰), suppression of the CNS function is possible. It is necessary to combine with caution with drugs that suppress the work of the central nervous system.

Combined use with medications that exert ototoxic effects (such as gentamicin), can mask the manifestations of ototoxicity (dizziness and tinnitus).

Simultaneous admission with theophylline (daily dosage - 400 mg once) reduces the indicator of cetirizine clearance (-16%), but there was no change in theophylline elimination.

In the case of Zestra (in connection with the presence of pseudoephedrine in its composition), it is required to abandon other sympathomimetics (such as mezaton or naphthysine), tricyclics (among them imipramine with amitriptyline), anorexigenic drugs (mazindol with desopimonone), MAO inhibitors (pyrazidol nialamide) and furazolidone - this combination can dramatically increase the level of blood pressure.

Pseudoephedrine can weaken the action of sympatholytics (such as octadine with reserpine), as well as blockers of β-adrenergic receptors (among them pindolol with nadolol).

In the case of a combination of pseudoephedrine and levodopa, as well as cardiac glycosides, the likelihood of developing ventricular arrhythmias in severe form is increased.

[8],

Storage conditions

Keep the medicine required in a place that is closed from moisture and sun, inaccessible to young children. Storage temperature should not exceed 25  ^o  C.

[9]

Shelf life

Zestra is suitable for use for 3 years from the date of manufacture of the medicine.