Antihistamines description. Antihistamines

There are several groups of medicines used for allergic diseases. This:

• antihistamines;
• membrane stabilizing drugs - preparations of cromoglycic acid () and ketotifen;
• topical and systemic glucocorticosteroids;
• intranasal decongestants.

In this article, we will only talk about the first group - antihistamines. These are drugs that block H1-histamine receptors and, as a result, reduce the severity of allergic reactions. Today, there are more than 60 antihistamines for systemic use. Depending on the chemical structure and the effects on the human body, these drugs are combined into groups, which we will talk about below.

What are histamine and histamine receptors, the principle of action of antihistamines

There are several types of histamine receptors in the human body.

Histamine is a biogenic compound formed as a result of a number of biochemical processes, and is one of the mediators involved in the regulation of vital body functions and playing a leading role in the development of many diseases.

Under normal conditions, this substance is in an inactive, bound state in the body, however, with various pathological processes (hay fever, and so on), the amount of free histamine increases many times, which is manifested by a number of specific and nonspecific symptoms.

Free histamine has the following effects on the human body:

• causes a spasm of smooth muscles (including the muscles of the bronchi);
• expands capillaries and lowers blood pressure;
• causes stagnation of blood in the capillaries and an increase in the permeability of their walls, which entails thickening of the blood and edema of the tissues surrounding the affected vessel;
• reflexively stimulates the cells of the adrenal medulla - as a result, adrenaline is released, which contributes to the narrowing of the arterioles and an increase in the heart rate;
• enhances the secretion of gastric juice;
• plays the role of a neurotransmitter in the central nervous system.

Outwardly, these effects are manifested as follows:

• bronchospasm occurs;
• the nasal mucosa swells - nasal congestion appears and mucus is released from it;
• itching, redness of the skin appears, all sorts of elements of the rash form on it - from spots to blisters;
• the digestive tract responds to an increase in the level of histamine in the blood with a spasm of the smooth muscles of the organs - there are pronounced cramping pains throughout the abdomen, as well as an increase in the secretion of digestive enzymes;
• on the part of the cardiovascular system, and can be noted.

In the body, there are special receptors for which histamine has an affinity - H1, H2 and H3-histamine receptors. In the development of allergic reactions, mainly H1-histamine receptors play a role, located in the smooth muscles of the internal organs, in particular, the bronchi, in the inner shell - the endothelium - of the vessels, in the skin, as well as in the central nervous system.

Antihistamines affect precisely this group of receptors, blocking the action of histamine in the form of competitive inhibition. That is, the drug does not displace the histamine already bound to the receptor, but occupies the free receptor, preventing histamine from attaching to it.

If all receptors are occupied, the body recognizes this and gives a signal to reduce the production of histamine. Thus, antihistamines prevent the release of new portions of histamine, and are also a means of preventing the occurrence of allergic reactions.

Classification of antihistamines

Several classifications of drugs in this group have been developed, but none of them is generally accepted.

Depending on the characteristics of the chemical structure, antihistamines are divided into the following groups:

• ethylenediamines;
• ethanolamines;
• alkylamines;
• quinuclidine derivatives;
• derivatives of alphacarboline;
• derivatives of phenothiazine;
• piperidine derivatives;
• derivatives of piperazine.

In clinical practice, the classification of antihistamines by generation has become more widely used, which today are distinguished by 3:

1. 1st generation antihistamines:

• diphenhydramine (diphenhydramine);
• doxylamine (donormil);
• clemastine (tavegil);
• chloropyramine (suprastin);
• mebhydrolin (diazolin);
• promethazine (pipolfen);
• quifenadine (fencarol);
• cyproheptadine (peritol) and others.

1. 2nd generation antihistamines:

• acrivastine (semprex);
• dimetindene (fenistil);
• terfenadine (histadine);
• azelastine (allergodil);
• loratadine (lorano);
• cetirizine (cetrin);
• bamipin (soventol).

1. 3rd generation antihistamines:

• fexofenadine (telfast);
• desloratodine (erius);
• levocetirizine.

1st generation antihistamines

Antihistamines of the 1st generation have a pronounced sedative effect.

For the predominant side effect, drugs in this group are also called sedatives. They interact not only with histamine receptors, but also with a number of other receptors, which determines their individual effects. They act for a short time, which is why they require repeated admission during the day. The effect comes quickly. Available in different dosage forms - for oral administration (in the form of tablets, drops) and parenteral administration (in the form of a solution for injection). Affordable.

With prolonged use of these drugs, their antihistamine effectiveness is significantly reduced, which necessitates a periodic - 1 time in 2-3 weeks - change of the drug.

Some 1st generation antihistamines are included in combination medicines for colds, as well as sleeping and anxiety medications.

The main effects of 1st generation antihistamines are:

• local anesthetic - associated with a decrease in membrane permeability to sodium; the most powerful local anesthetic agents in this group are promethazine and diphenhydramine;
• sedative - due to the high degree of penetration of drugs of this group through the blood-brain barrier (that is, into the brain); the severity of this effect is different for different drugs, it is most pronounced in doxylamine (it is often used as a hypnotic); the sedative effect increases with the simultaneous use of alcoholic beverages or the use of psychotropic drugs; when taking extremely high doses of the drug, instead of the effect of sedation, pronounced agitation is noted;
• anti-anxiety, sedative effect is also associated with the penetration of the active substance into the central nervous system; the most pronounced in hydroxyzine;
• anti-pumping and antiemetic - some representatives of this group of drugs inhibit the function of the labyrinth of the inner ear and reduce the stimulation of the receptors of the vestibular apparatus - they are sometimes used for Meniere's disease and motion sickness in transport; this effect is most pronounced in drugs such as diphenhydramine, promethazine;
• atropine-like action - cause dryness of the mucous membranes of the oral and nasal cavities, increased heart rate, visual impairment, urinary retention, constipation; can aggravate bronchial obstruction, lead to exacerbation of glaucoma and obstruction when - with these diseases are not used; these effects are most pronounced in ethylenediamines and ethanolamines;
• antitussive - drugs in this group, in particular, diphenhydramine, have an effect directly on the cough center located in the medulla oblongata;
• the antiparkinsonian effect is obtained by inhibiting the effects of acetylcholine with an antihistamine;
• antiserotonin effect - the drug binds to serotonin receptors, alleviating the condition of patients suffering from migraines; especially pronounced in cyproheptadine;
• expansion of peripheral vessels - leads to a decrease in blood pressure; the most pronounced in phenothiazine preparations.

Since drugs in this group have a number of undesirable effects, they are not the drugs of choice for treating allergies, but they are still often used for it.

Below are some of the most commonly used representatives of the drugs in this group.

Diphenhydramine (diphenhydramine)

One of the first antihistamines. It has a pronounced antihistamine activity, in addition, it has a local anesthetic effect, and also relaxes the smooth muscles of internal organs and is a weak antiemetic agent. Its sedative effect is similar in strength to the effects of antipsychotics. In high doses, it also has a hypnotic effect.

It is rapidly absorbed when taken orally, penetrates the blood-brain barrier. Its half-life is about 7 hours. Undergoes biotransformation in the liver, excreted by the kidneys.

It is used for all kinds of allergic diseases, as a sedative and hypnotic, as well as in the complex therapy of radiation sickness. Less commonly used for vomiting of pregnant women, seasickness.

Inside it is prescribed in the form of tablets of 0.03-0.05 g 1-3 times a day for 10-14 days, or one tablet at bedtime (as a sleeping pill).

Intramuscularly inject 1-5 ml of a 1% solution, intravenously drip - 0.02-0.05 g of the drug in 100 ml of 0.9% sodium chloride solution.

It can be used in the form of eye drops, rectal suppositories, or creams and ointments.

Side effects of this drug are: short-term numbness of the mucous membranes, headache, dizziness, nausea, dry mouth, weakness, drowsiness. Side effects pass on their own, after dose reduction or complete withdrawal of the drug.

Contraindications are pregnancy, lactation, prostatic hypertrophy, angle-closure glaucoma.

Chloropyramine (Suprastin)

It has antihistaminic, anticholinergic, myotropic antispasmodic activity. It also has antipruritic and sedative effects.

It is rapidly and completely absorbed when taken orally, the maximum concentration in the blood is observed 2 hours after ingestion. Penetrates the blood-brain barrier. Biotransformed in the liver, excreted by the kidneys and with feces.

It is prescribed for all kinds of allergic reactions.

It is used orally, intravenously and intramuscularly.

Inside, you should take 1 tablet (0.025 g) 2-3 times a day, with meals. The daily dose can be increased to a maximum of 6 tablets.

In severe cases, the drug is administered parenterally - intramuscularly or intravenously, 1-2 ml of a 2% solution.

When taking the drug, side effects are possible such as general weakness, drowsiness, a decrease in the speed of reactions, impaired coordination of movements, nausea, dry mouth.

Strengthens the effect of hypnotics and sedatives, as well as narcotic analgesics and alcohol.

Contraindications are similar to those of diphenhydramine.

Clemastine (tavegil)

In terms of structure and pharmacological properties, it is very close to diphenhydramine, but it acts for a longer period (within 8-12 hours after ingestion) and is more active.

The sedative effect is moderate.

It is applied orally 1 tablet (0.001 g) before meals with plenty of water, 2 times a day. In severe cases, the daily dose can be increased by 2, maximum - 3 times. The course of treatment is 10-14 days.

It can be used intramuscularly or intravenously (within 2-3 minutes) - 2 ml of a 0.1% solution per dose, 2 times a day.

Side effects are rare with this drug. Headache, drowsiness, nausea and vomiting, constipation are possible.

It is prescribed with caution to persons whose profession requires intense mental and physical activity.

Contraindications are standard.

Mebhydrolin (diazolin)

In addition to the antihistamine, it has an anticholinergic and. The sedative and hypnotic effects are extremely weak.

Ingestion is slowly absorbed. The half-life is only 4 hours. Biotransformed in the liver, excreted in the urine.

It is applied orally, after meals, in a single dose of 0.05-0.2 g, 1-2 times a day for 10-14 days. The maximum single dose for an adult is 0.3 g, the daily dose is 0.6 g.

Generally well tolerated. Sometimes it can cause dizziness, irritation of the gastric mucosa, blurred vision, urinary retention. In especially rare cases - when taking a large dose of the drug - a slowdown in the speed of reactions and drowsiness.

Contraindications are inflammatory diseases of the gastrointestinal tract, angle-closure glaucoma and prostatic hypertrophy.

2nd generation antihistamines

Antihistamines of the second generation are characterized by high efficacy, rapid onset of action and a minimum of side effects, but some of their representatives can cause life-threatening arrhythmias.

The purpose of the development of drugs in this group was to minimize sedative and other side effects while maintaining or even stronger antiallergic activity. And it succeeded! Antihistamines of the 2nd generation have a high affinity specifically for H1-histamine receptors, practically without affecting choline and serotonin receptors. The advantages of these drugs are:

• rapid onset of action;
• long duration of action (the active substance binds to the protein, which ensures its longer circulation in the body; in addition, it accumulates in organs and tissues, and is also slowly excreted);
• additional mechanisms of antiallergic effects (suppress the accumulation of eosinophils in the respiratory tract, which is associated with the intake of an allergen, and also stabilize the membranes of mast cells), which determine a wider range of indications for their use (,);
• with prolonged use, the effectiveness of these drugs does not decrease, that is, the effect of tachyphylaxis is absent - there is no need to periodically change the drug;
• since these drugs do not penetrate or penetrate in extremely small quantities through the blood-brain barrier, their sedative effect is minimal and is observed only in patients who are especially sensitive in this regard;
• do not interact with psychotropic drugs and ethyl alcohol.

One of the most adverse effects of 2nd generation antihistamines is their ability to cause fatal arrhythmias. The mechanism of their occurrence is associated with the blocking of the potassium channels of the heart muscle by the antiallergic agent, which leads to an extension of the QT interval and the occurrence of arrhythmias (as a rule, fibrillation or flutter of the ventricles). This effect is most pronounced in drugs such as terfenadine, astemizole and ebastine. The risk of its development increases significantly with an overdose of these drugs, as well as in the case of a combination of their intake with antidepressants (paroxetine, fluoxetine), antifungal (intraconazole and ketoconazole) and some antibacterial agents (antibiotics from the macrolide group - clarithromycin, oleandomycin), erythromycin (disopyramide, quinidine), when the patient consumes grapefruit juice and expressed.

The main form of release of 2nd generation antihistamines is tableted, while parenteral drugs are absent. Some drugs (such as levocabastine, azelastine) are available in the form of creams and ointments and are intended for topical administration.

Let's consider the main drugs in this group in more detail.

Acrivastin (Semprex)

It is well absorbed when taken orally, begins to act within 20-30 minutes after ingestion. The half-life is 2-5.5 hours, it penetrates the blood-brain barrier in an insignificant amount, is excreted in the urine unchanged.

Blocks H1-histamine receptors, to a small extent has a sedative and anticholinergic effect.

It is used for all kinds of allergic diseases.

On the background of admission, in some cases, drowsiness and a decrease in the reaction rate are possible.

The drug is contraindicated during pregnancy, lactation, with severe, severe coronary and, as well as children under 12 years of age.

Dimetindene (fenistil)

In addition to the antihistamine, it has weak anticholinergic, anti-bradykinin and sedative effects.

It is quickly and completely absorbed when taken orally, the bioavailability (degree of assimilation) is about 70% (in comparison, when using the cutaneous forms of the drug, this figure is much lower - 10%). The maximum concentration of the substance in the blood is observed 2 hours after ingestion, the half-life is 6 hours for the usual and 11 hours for the retard form. It penetrates through the blood-brain barrier, is excreted in bile and urine in the form of metabolic products.

Apply the drug internally and topically.

Inside, adults take 1 retard capsule at night or 20-40 drops 3 times a day. The course of treatment is 10-15 days.

The gel is applied to the affected skin 3-4 times a day.

Side effects are rare.

Only the 1st trimester of pregnancy is a contraindication.

Strengthens the effect on the central nervous system of alcohol, sleeping pills and tranquilizers.

Terfenadine (histadine)

In addition to antiallergic, it has a weak anticholinergic effect. It has no pronounced sedative effect.

It is well absorbed when taken orally (bioavailability is 70%). The maximum concentration of the active substance in the blood is noted after 60 minutes. It does not penetrate the blood-brain barrier. Biotransformed in the liver with the formation of fexofenadine, excreted in feces and urine.

The antihistamine effect develops in 1-2 hours, reaches a maximum in 4-5 hours, and lasts for 12 hours.

The indications are the same as for other drugs in this group.

Assign 60 mg 2 times a day or 120 mg 1 time a day in the morning. The maximum daily dose is 480 mg.

In some cases, when taking this drug, the patient develops such side effects as erythema, fatigue, headache, drowsiness, dizziness, dry mucous membranes, galactorrhea (milk flow from the mammary glands), increased appetite, nausea, vomiting, in case of an overdose - ventricular arrhythmias.

Contraindications are pregnancy and lactation.

Azelastine (allergodil)

Blocks histamine H1 receptors, and also prevents the release of histamine and other allergy mediators from mast cells.

It is rapidly absorbed in the digestive tract and from the mucous membranes, the half-life is as much as 20 hours. It is excreted in the form of metabolites in the urine.

They are used, as a rule, for allergic rhinitis and.

When taking the drug, side effects are possible such as dryness and irritation of the nasal mucosa, bleeding from it and taste disturbances with intranasal use; irritation of the conjunctiva and a feeling of bitterness in the mouth - when using eye drops.

Contraindications: pregnancy, lactation, children under 6 years of age.

Loratadin (lorano, claritin, lorizal)

Long-acting histamine H1 receptor blocker. The effect after a single dose of the drug lasts for a day.

There is no pronounced sedative effect.

When taken orally, it is absorbed quickly and completely, reaches a maximum concentration in the blood after 1.3-2.5 hours, half is excreted from the body after 8 hours. Biotransformed in the liver.

The indications are any allergic diseases.

It is generally well tolerated. In some cases, dry mouth, increased appetite, nausea, vomiting, sweating, pain in joints and muscles, hyperkinesis are possible.

Contraindication is hypersensitivity to loratadine and lactation.

Prescribe with caution to pregnant women.

Bamipin (soventol)

Topical H1-histamine receptor blocker. It is prescribed for allergic skin lesions (urticaria), contact allergies, as well as for frostbite and burns.

The gel is applied in a thin layer to the affected skin. After half an hour, reapplication of the drug is possible.

Cetirizine (cetrin)

Metabolite of hydroxyzine.

It has the ability to freely penetrate the skin and quickly accumulate in it - this determines the rapid onset of action and high antihistamine activity of this drug. There is no arrhythmogenic effect.

It is rapidly absorbed when taken orally, its maximum concentration in the blood is noted 1 hour after ingestion. The half-life is 7-10 hours, but in case of impaired renal function, it lengthens to 20 hours.

The range of indications for use is the same as for other antihistamines. However, due to the peculiarities of cetirizine, it is the drug of choice in the treatment of diseases manifested by skin rashes - urticaria and allergic dermatitis.

Take 0.01 g in the evening or 0.005 g twice a day.

Side effects are rare. These are drowsiness, dizziness and headache, dry mouth, nausea.

3rd generation antihistamines

Antihistamines of the third generation have high antiallergic activity and are devoid of arrhythmogenic effect.

These drugs are active metabolites (metabolic products) of the previous generation. They lack the cardiotoxic (arrhythmogenic) effect, but retained the advantages of their predecessors. In addition, 3rd generation antihistamines have a number of effects that enhance their antiallergic activity, which is why their effectiveness in treating allergies is often higher than that of the substances from which they are produced.

Fexofenadine (Telfast, Allegra)

It is a metabolite of terfenadine.

Blocks H1-histamine receptors, prevents the release of allergy mediators from mast cells, does not interact with cholinergic receptors, does not inhibit the central nervous system. It is excreted unchanged with feces.

The antihistamine effect develops within 60 minutes after a single dose of the drug, reaches a maximum after 2-3 hours, lasts for 12 hours.

Side effects such as dizziness, headache, weakness are rare.

Desloratadine (Erius, Eden)

It is an active metabolite of loratadine.

It has anti-allergic, anti-edematous and antipruritic effects. When taken in therapeutic doses, it practically does not have a sedative effect.

The maximum concentration of the drug in the blood is reached 2-6 hours after ingestion. The half-life is 20-30 hours. Does not penetrate the blood-brain barrier. It is metabolized in the liver, excreted in the urine and feces.

In 2% of cases, while taking the drug, a headache, increased fatigue and dry mouth may appear.

With renal failure, appoint with caution.

Contraindications are hypersensitivity to desloratadine. As well as periods of pregnancy and lactation.

Levocetirizine (Aleron, L-cet)

Derivative of cetirizine.

The affinity for H1-histamine receptors in this drug is 2 times higher than that of its predecessor.

Facilitates the course of allergic reactions, has a decongestant, anti-inflammatory, antipruritic effect. Practically does not interact with serotonin and cholinergic receptors, does not have a sedative effect.

When taken orally, it is rapidly absorbed, its bioavailability tends to 100%. The drug develops in 12 minutes after a single dose. The maximum concentration in blood plasma is observed after 50 minutes. It is excreted mainly by the kidneys. Excreted in breast milk.

Contraindicated in case of hypersensitivity to levocetirizine, severe renal failure, severe galactose intolerance, lactase enzyme deficiency or impaired absorption of glucose and galactose, as well as during pregnancy and lactation.

Side effects are rare: headache, drowsiness, weakness, fatigue, nausea, dry mouth, muscle pain, palpitations.

Antihistamines and pregnancy, lactation

Therapy for allergic diseases in pregnant women is limited, since many drugs are dangerous for the fetus, especially in the first 12-16 weeks of pregnancy.

When prescribing antihistamines for pregnant women, the degree of their teratogenicity should be taken into account. All medicinal substances, in particular antiallergic ones, are divided into 5 groups depending on how dangerous they are to the fetus:

A - special studies have shown that there is no harmful effect of the drug on the fetus;

B - during experiments on animals, no negative effects on the fetus were found, special studies on humans were not carried out;

C - experiments on animals revealed a negative effect of the drug on the fetus, however, in relation to humans, it has not been proven; drugs in this group are prescribed to a pregnant woman only when the expected effect exceeds the risk of its harmful effects;

D - the negative effect of this drug on the human fetus has been proven, however, its appointment is justified in certain situations that threaten the life of the mother, when safer drugs were ineffective;

X - the drug is certainly dangerous to the fetus, and its harm exceeds any theoretically possible benefit to the mother's body. These drugs are absolutely contraindicated in pregnant women.

Systemic antihistamines during pregnancy are used only when the expected benefit outweighs the potential risk to the fetus.

Of the drugs in this group, none are included in category A. Category B includes drugs of the 1st generation - tavegil, diphenhydramine, peritol; 2nd generation - loratadine, cetirizine. Category C includes allergodil, pipolfen.

The drug of choice for the treatment of allergic diseases during pregnancy is cetirizine. Loratadine and fexofenadine are also recommended.

The use of astemizole and terfenadine is unacceptable due to their pronounced arrhythmogenic and embryotoxic effects.

Desloratadine, suprastin, levocetirizine cross the placenta, therefore it is categorically contraindicated for use by pregnant women.

With regard to the lactation period, we can say the following ... Again, uncontrolled intake of these drugs by a nursing mother is unacceptable, since no studies have been conducted on the degree of their penetration into breast milk. If it is necessary for these drugs, a young mother is allowed to take one that is allowed for her child (depending on age).

In conclusion, I would like to note that even despite the fact that this article describes in detail the drugs most often used in therapeutic practice and indicates their dosages, the patient should start taking them only after consulting a doctor!

Many home first-aid kits contain medicines, the purpose and mechanism of action of which people do not understand. Antihistamines are also such drugs. Most allergy sufferers choose their own medicines, calculate the dosage and course of therapy, without consulting a specialist.

Antihistamines - what are they in simple terms?

The term is often misinterpreted. Many people think that these are just drugs for allergies, but they are intended to treat other diseases as well. Antihistamines are a group of medicines that block the immune response to external stimuli. These include not only allergens, but also viruses, fungi and bacteria (infectious agents), toxins. The medications in question prevent the occurrence of:

• swelling of the mucous membranes of the nose and throat;
• redness, blisters on the skin;
• itching;
• excessive secretion of gastric juice;
• narrowing of blood vessels;
• muscle spasms;
• swelling.

How do antihistamines work?

The main protective role in the human body is played by leukocytes or white blood cells. There are several types of them, one of the most important is mast cells. After maturation, they circulate through the bloodstream and integrate into connective tissues, becoming part of the immune system. When hazardous substances enter the body, mast cells release histamine. It is a chemical essential for the regulation of digestive processes, oxygen metabolism, and blood circulation. Its excess leads to allergic reactions.

In order for histamine to provoke negative symptoms, it must be absorbed by the body. For this, there are special H1 receptors located in the inner lining of blood vessels, smooth muscle cells and the nervous system. How antihistamines work: The active ingredients in these medicines trick the H1 receptors. Their structure and structure is very similar to the substance in question. Medicines compete with histamine and are absorbed by receptors instead of it, without causing allergic reactions.

As a result, the chemical that triggers the unwanted symptoms remains inactive in the blood and is later excreted naturally. The antihistamine effect depends on how many H1 receptors the drug has been able to block. For this reason, it is important to start treatment as soon as the first allergy symptoms appear.

The duration of therapy depends on the generation of the drug and the severity of pathological signs. How long to take antihistamines is up to the doctor to decide. Some drugs can be used no more than 6-7 days, modern pharmacological agents of the latest generation are less toxic, therefore, they can be used for 1 year. It is important to consult a specialist before taking it. Antihistamines can build up in the body and cause poisoning. Some people subsequently become allergic to these medicines.

How often can antihistamines be taken?

Most of the manufacturers of the described products release them in a convenient dosage, which involves the use of only 1 time per day. The question of how to take antihistamines, depending on the frequency of occurrence of negative clinical manifestations, is decided with the doctor. The presented group of medicines refers to symptomatic methods of therapy. They must be used whenever signs of illness appear.

New antihistamines can also be used as prophylaxis. If contact with an allergen cannot be definitely avoided (poplar fluff, ragweed flowering, etc.), you should use the medicine in advance. Taking antihistamines first will not only alleviate negative symptoms, but eliminate their appearance. The H1 receptors will already be blocked when the immune system tries to initiate a defense response.

Antihistamines - list

The very first drug of this group was synthesized in 1942 (Fenbenzamine). From that moment on, a massive study of substances capable of blocking H1 receptors began. To date, there are 4 generations of antihistamines. Early drug options are rarely used due to unwanted side effects and toxic effects on the body. Modern medicines are characterized by maximum safety and quick results.

Antihistamines of the 1st generation - list

This type of pharmacological agent has a short-term effect (up to 8 hours), can be addictive, sometimes it provokes poisoning. Antihistamines of the 1st generation remain popular only because of their low cost and pronounced sedative (sedative) effect. Names:

• Daedalon;
• Bicarfen;
• Suprastin;
• Tavegil;
• Diazolin;
• Clemastine;
• Diprazine;
• Loredix;
• Pipolfen;
• Setastin;
• Dimebon;
• Cyproheptadine;
• Fenkarol;
• Peritol;
• Quifenadine;
• Dimetindene;
• other.

Antihistamines 2nd generation - list

35 years later, the first H1 receptor blocker without sedation and toxic effects on the body was released. Unlike their predecessors, 2nd generation antihistamines work much longer (12-24 hours), do not cause addiction and do not depend on food and alcohol intake. They provoke fewer dangerous side effects and do not block other receptors in tissues and blood vessels. New generation antihistamines - list:

• Taldan;
• Astemizole;
• Terfenadine;
• Bronal;
• Allergodil;
• Fexofenadine;
• Rupafin;
• Trexil;
• Loratadine;
• Histadil;
• Zyrtec;
• Ebastine;
• Astemisan;
• Clarisens;
• Histalong;
• Cetrin;
• Semprex;
• Kestin;
• Acrivastine;
• Gismanal;
• Cetirizine;
• Levocabastine;
• Azelastine;
• Histimet;
• Lorahexal;
• Claridol;
• Rupatadine;
• Lomilan and analogues.

Antihistamines 3rd generation

Based on previous drugs, scientists have obtained stereoisomers and metabolites (derivatives). At first, these antihistamines were marketed as a new subgroup of medicines, or 3rd generation:

• Glenzet;
• Ksizal;
• Ceser;
• Suprastinex;
• Fexofast;
• Zodak Express;
• L-Cet;
• Loratek;
• Feksadin;
• Erius;
• Desal;
• NeoClaritin;
• Lordestine;
• Telfast;
• Fexofen;
• Allegra.

Later, this classification caused controversy and controversy in the scientific community. To make a final decision on the listed funds, a group of experts was assembled for independent clinical trials. According to the evaluation criteria, third-generation allergy drugs should not affect the functioning of the central nervous system, produce a toxic effect on the heart, liver and blood vessels, and interact with other medications. According to the research results, none of the indicated drugs meets these requirements.

Antihistamines 4 generations - list

In some sources, Telfast, Suprastinex and Erius are referred to this type of pharmacological agent, but this is an erroneous statement. Antihistamines of the 4th generation have not yet been developed, as well as the third. There are only improved forms and derivatives of the previous drug options. The most modern drugs are still 2 generations.

The selection of funds from the described group should be carried out by a specialist. Some people are better off with 1st generation allergy medications due to the need for sedation; others do not. Similarly, the doctor recommends the form of release of the medication, depending on the symptoms. Systemic drugs are prescribed with pronounced signs of the disease, in other cases, local remedies can be dispensed with.

Antihistamine tablets

Oral medications are necessary for the rapid removal of clinical manifestations of pathology that affect several body systems. Internal antihistamines begin to act within an hour and effectively relieve swelling of the throat and other mucous membranes, relieve a runny nose, lacrimation and skin symptoms of the disease.

Effective and safe allergy pills:

• Fexofen;
• Alersis;
• Tsetrilev;
• Altiva;
• Rolinoz;
• Telfast;
• Amertil;
• Eden;
• Fexofast;
• Cetrin;
• Allergomax;
• Zodak;
• Tigofast;
• Allertek;
• Cetrinal;
• Eridez;
• Trexil Neo;
• Zilola;
• L-Cet;
• Alerzin;
• Glenzet;
• Ksizal;
• Aleron Neo;
• Lordes;
• Erius;
• Allergostop;
• Fribris and others.

Antihistamine drops

In this dosage form, both local and systemic drugs are produced. Allergy drops for oral administration;

• Zyrtec;
• Desal;
• Fenistil;
• Zodak;
• Ksizal;
• Parlazin;
• Backorder;
• Allergonix and analogues.

Topical antihistamines for the nose:

• Tizine Allergy;
• Allergodil;
• Lekrolin;
• Cromohexal;
• Sanorin Anallergin;
• Vibrocil and others.

Currently, in the special literature, opinions differ as to which antiallergic drugs should be classified as the second and third generation. In this regard, the list of 2nd generation antihistamines will have its own characteristics, depending on the point of view of modern pharmacists.

By what criteria are antihistamines classified into the second group?

According to the first point of view, second-generation drugs are all those anti-allergic drugs that are devoid of sedation because they do not enter the brain through the blood-brain barrier.

The second and most common point of view is that the second generation of antihistamines should include only those that, although they do not affect the nervous system, are capable of causing changes in the heart muscle. Medicines that do not act on the heart and nervous system have been classified as the third generation of antihistamines.

According to the third point of view, only one drug with antihistaminic properties, ketotifen, belongs to the second generation, because it has a membrane stabilizing effect. And all those drugs that stabilize the mast cell membrane, but do not cause sedation, make up the third generation of antihistamines.

Why are antihistamines so named?

Histamine is an essential substance that is predominantly found in the mast cells of connective tissue and blood basophils. Released under the influence of various factors from these cells, it binds to the H 1 and H 2 receptors:

• H 1 -receptors, when interacting with histamine, cause bronchospasm, contraction of smooth muscles, expand capillaries and increase their permeability.
• H 2 -receptors stimulate an increase in acidity in the stomach, affect the heart rate.

Indirectly, histamine can cause severe itching, stimulating the release of catecholamines from adrenal cells, increasing the secretion of the salivary and lacrimal glands, and accelerating intestinal motility.

Antihistamines bind to H 1 and H 2 receptors and block the action of histamine.

List of drugs of the second group

According to the most common classification of antihistamines, the second generation includes:

• dimethindene,
• loratadine,
• ebastine,
• cyproheptadine,
• azelastine,
• acrivastine.

All of these drugs do not enter the brain and therefore do not induce sedation. However, the possible development of cardiotoxic action limits the use of this group of drugs in the elderly and those who suffer from heart disease.

Enhances myocardial damage when treated with second-generation antihistamines, the simultaneous administration of antifungal agents and some antibiotics, for example, clarithromycin, erythromycin, itraconazole and ketoconazole. You should also refrain from consuming grapefruit juice and antidepressants.

Dimetindene (fenistil)

It is available in the form of drops, gel and capsules for oral administration. It is one of the few drugs that can be used in children in the first year of life, with the exception of the neonatal period.

Fenistil is well absorbed internally and has a pronounced antiallergic effect, lasting after 1 dose for about 6-11 hours.

The drug is effective for pruritus, eczema, drug and food allergies, insect bites, itchy dermatoses and exudative-catarrhal diathesis in children. Its other purpose is to remove mild household and sunburns.

Features of the application. It is one of the few second-generation drugs that still crosses the blood-brain barrier, so it can slow down the response while driving. In this connection, it should be prescribed with extreme caution to drivers, and even more so not to use it during work that requires a quick reaction.

When applying the gel to the skin, protect the area from direct sunlight.

Dimetindene is contraindicated during the first trimester of pregnancy and in the neonatal period. It is used with caution in the second and third trimesters of pregnancy, with prostate adenoma, angle-closure glaucoma.

Loratadin (claritin, lomilan, lotaren)

Like other drugs in this group, it effectively treats all kinds of allergic diseases, especially allergic rhinitis, conjunctivitis, nasopharyngitis, angioedema, urticaria, endogenous itching. The drug is available in the form of tablets and syrup for oral administration, and is also part of multicomponent antiallergic gels and ointments for local treatment.

Effective for pseudo-allergic reactions, hay fever, urticaria, itchy dermatoses. As an aid, it is prescribed for bronchial asthma.

Features of the application. May cause sedation in the elderly, not recommended during pregnancy and breastfeeding. Many drugs reduce the effectiveness of loratadine or increase its side effects, so you should definitely consult your doctor before taking it.

Ebastin (Kestin)

Also belongs to the group of second generation antihistamines. Its distinctive feature is the lack of interaction with ethanol, so it is not contraindicated for the use of medicines containing alcohol. Simultaneous administration with ketoconazole increases the toxic effect on the heart, which can lead to fatal consequences.

Ebastine is prescribed for allergic rhinitis, urticaria and other diseases accompanied by excess histamine release.

Cyproheptadine (peritol)

This drug for the treatment of allergic reactions can be prescribed to children from 6 months. Like other drugs in this group, cyproheptadine has a strong and long-term effect, eliminating allergy symptoms. A distinctive feature of peritol is the relief of migraine headaches, a sedative effect, a decrease in excess secretion of growth hormone in acromegaly. Cyproheptadine is prescribed for toxicoderma, neurodermatitis, in the complex therapy of chronic pancreatitis, serum sickness.

Azelastine (allergodil)

This drug works well for allergy manifestations such as allergic rhinitis and conjunctivitis. Available as a nasal spray and eye drops. In pediatrics, it is prescribed for children from 4 years old (eye drops) and from 6 years old (spray). The duration of the course of treatment with azelastine, on the recommendation of a doctor, can last up to 6 months.

From the nasal mucosa, the drug is well absorbed into the general bloodstream and has a systemic effect on the body.

Acrivastin (Semprex)

The drug weakly penetrates the blood-brain barrier, therefore it does not have a sedative effect, however, vehicle drivers and those whose work requires quick and accurate action should refrain from taking it.

Acrivastin differs from other representatives of this group in that it begins to act within the first 30 minutes, and the maximum effect on the skin is observed within 1.5 hours after ingestion.

Drugs of the second group, about which there is disagreement in scientific circles

Mebhydrolin (diazolin)

Most experts classify diazolin as the first generation of antihistamines, while others, due to the minimally pronounced sedative effect, classify this agent as the second. Be that as it may, diazolin is widely used not only in adults, but also in pediatric practice, being considered one of the most inexpensive and available medicines.

Desloratadine (edem, erius)

It is most often referred to as the third generation of antihistamines because it is an active metabolite of loratadine.

Cetirizine (zodak, cetrin, paralazin)

Most researchers classify this drug as the second generation of antihistamines, although some confidently classify it as the third, because it is an active metabolite of hydroxyzine.

Zodak is well tolerated and rarely causes side effects. It is available in the form of drops, tablets and syrup for oral administration. With a single dose of the drug, it has a therapeutic effect throughout the day, so it can be taken only once a day.

Cetirizine relieves allergy symptoms, does not cause sedation, prevents the development of smooth muscle spasm and swelling of surrounding tissues. It is effective for hay fever, allergic conjunctivitis, urticaria, eczema, and removes itching well.

Features of the application. If the drug is prescribed in large doses, then you should refrain from driving vehicles, as well as work that requires a quick response. When used together with alcohol, cetirizine can increase its negative effects.

The duration of the course of treatment with this drug can be from 1 to 6 weeks.

Fexofenadine (Telfast)

Most researchers also belong to the third generation of antihistamines, because it is an active metabolite of terfenadine. It can be used by those whose activities are related to driving vehicles, as well as those suffering from heart disease.

Content

A small number of people are fortunate enough to never feel allergic reactions in their lives. Most have to deal with them periodically. To cope with allergies for both adults and children, effective antihistamines will help. Such funds help to eliminate negative reactions in the body to certain stimuli. There is a wide range of anti-allergenic medicines on the market. It is desirable for each person to be able to understand them.

What are antihistamines

These are drugs that work to suppress the action of free histamine. This substance is released from the cells of the connective tissue, which enter the immune system, when an allergen enters the human body. When histamine interacts with certain receptors, edema, itching, and rashes begin. These are all symptoms of allergies. Antihistamine drugs block the aforementioned receptors, making the patient's condition easier.

Indications for use

A doctor must prescribe antihistamines, making an accurate diagnosis. As a rule, their reception is advisable in the presence of such symptoms and diseases:

• early atopic syndrome in a child;
• seasonal or perennial rhinitis;
• negative reaction to plant pollen, animal hair, household dust, some medications;
• severe bronchitis;
• angioedema;
• anaphylactic shock;
• food allergies;
• enteropathy;
• bronchial asthma;
• atopic dermatitis;
• conjunctivitis caused by exposure to allergens;
• chronic, acute and other forms of urticaria;
• allergic dermatitis.

Antihistamines - list

There are several generations of anti-allergic medicines. Their classification:

1. New generation drugs. The most modern medicines. They act very quickly, and the effect of their use lasts for a long time. Block H1 receptors, suppressing allergy symptoms. Antihistamines of this group do not impair heart function, therefore they are considered one of the safest.
2. 3rd generation drugs. Active metabolites with very few contraindications. They provide a fast, stable result, and they are gentle on the heart.
3. Preparations of the 2nd generation. Non-sedative medications. They have a small list of side effects, they put a lot of stress on the heart. Does not affect mental or physical performance. Antiallergic drugs of the second generation are often prescribed when a rash, itching occurs.
4. 1st generation drugs. Sedatives that last up to several hours. They eliminate allergy symptoms well, but they have many side effects and contraindications. From their use always tends to sleep. At the present time, such drugs are prescribed very rarely.

Antiallergic drugs of a new generation

It is not possible to list all the drugs in this group. It is worth taking apart a few of the best ones. This list opens with the following drug:

• name: Fexofenadine (analogues - Allegra (Telfast), Fexofast, Tigofast, Altiva, Fexofen-Sanovel, Kestin, Norastemizol);
• action: blocks H1-histamine receptors, relieves all allergy symptoms;
• pluses: it acts quickly and for a long time, is available in tablets and suspensions, is well tolerated by patients, has not too many side effects, is dispensed without a prescription;
• cons: not suitable for children under six years old, pregnant women, nursing mothers, incompatible with antibiotics.

Another drug worthy of attention:

• name: Levocetirizine (analogs - Aleron, Zilola, Alerzin, Glenzet, Aleron Neo, Rupafin);
• action: antihistamine, blocks H1 receptors, reduces vascular permeability, has antipruritic and antiexudative effects;
• pluses: there are tablets, drops, syrup on sale, the drug acts in just a quarter of an hour, there are not many contraindications, there is compatibility with many drugs;
• cons: a wide range of strong side effects.

• name: Desloratadine (analogs - Lordes, Allergostop, Alersis, Fribris, Edem, Eridez, Alergomax, Erius);
• action: antihistamine, antipruritic, decongestant, relieves rash, runny nose, nasal congestion, reduces bronchial hyperactivity;
• pluses: a new generation of allergy medicine is well absorbed and works quickly, relieves allergy symptoms for a day, does not have a negative effect on the central nervous system and the speed of reactions, does not harm the heart, joint administration with other drugs is allowed;
• cons: not suitable for pregnancy and lactation, prohibited for children under 12 years old.

Antihistamines 3 generations

The following drug is popular and has many good reviews:

• name: Desal (analogues - Ezlor, Nalorius, Eliza);
• action: antihistamine, relieves swelling and spasms, relieves itching, rash, allergic rhinitis;
• pluses: it is available in tablets and solution, does not give a sedative effect and does not affect the speed of reactions, quickly works and acts for about a day, is quickly absorbed;
• cons: bad for the heart, many side effects.

Experts respond well to such a drug:

• name: Suprastinex;
• action: antihistamine, prevents the appearance of allergic manifestations and facilitates their course, helps with itching, peeling, sneezing, edema, rhinitis, lacrimation;
• pluses: it is available in drops and tablets, there is no sedative, anticholinergic and antiserotonergic effect, the drug acts in an hour and continues to work for a day;
• cons: there are a number of strict contraindications.

The group of third-generation drugs also includes the following:

• name: Ksizal;
• action: a pronounced antihistamine, not only relieves allergy symptoms, but also prevents their appearance, reduces the permeability of the walls of blood vessels, fights sneezing, lacrimation, edema, urticaria, inflammation of the mucous membranes;
• pluses: sold in tablets and drops, does not have a sedative effect, is well absorbed;
• cons: has a wide range of side effects.

Antiallergenic drugs of the 2nd generation

A well-known series of drugs, represented by tablets, drops, syrups:

• name: Zodak;
• action: prolonged anti-allergic, helps against itching, flaking of the skin, relieves swelling;
• pluses: subject to the dosages and rules of admission, it does not cause drowsiness, quickly begins to act, does not cause addiction;
• cons: prohibited for pregnant women and children.

The next second generation drug:

• name: Cetrin;
• action: antihistamine, good for edema, hyperemia, itching, peeling, rhinitis, urticaria, reduces capillary permeability, relieves spasms;
• pluses: there are drops and syrup on sale, low cost, lack of anticholinergic and antiserotonin effects, if the dosage is observed, it does not affect concentration, does not cause addiction, side effects are extremely rare;
• cons: there are a number of strict contraindications, overdose is very dangerous.

Another very good drug in this category:

• name: Lomilan;
• action: a systemic blocker of H1 receptors, relieves all allergy symptoms: itching, peeling, swelling;
• pluses: does not affect the heart and the central nervous system, is completely excreted from the body, helps to overcome allergies well and quickly, is suitable for constant use;
• cons: many contraindications and side effects.

1st generation tools

Antihistamines of this group appeared a very long time ago and are now used less often than others, nevertheless they deserve attention. Here is one of the most famous:

• name: Diazolin;
• action: antihistamine, H1-receptor blocker;
• pluses: gives an anesthetic effect, lasts a long time, helps well with dermatoses with itchy skin, rhinitis, cough, food and drug allergies, insect bites, is cheap;
• cons: there is a moderately pronounced sedative effect, many side effects, contraindications.

This one also belongs to the drugs of the 1st generation:

• name: Suprastin;
• action: anti-allergic;
• pluses: available in tablets and ampoules;
• cons: pronounced sedative effect, the effect is short-lived, there are a lot of contraindications, side effects.

The last representative of this group:

• name: Fenistil;
• action: histamine blocker, antipruritic;
• pluses: available in the form of a gel, emulsion, drops, tablets, relieves skin irritation well, relieves a little pain, inexpensive;
• cons: the effect after application passes quickly.

Allergy tablets for children

Most antihistamines have strict age-related contraindications. The question would be quite reasonable: how to treat very young allergy sufferers who suffer at least as often as adults? As a rule, children are prescribed drugs in the form of drops, suspensions, and not tablets. Means allowed for the treatment of infants and persons under 12 years of age:

• Diphenhydramine;
• Fenistil (drops are suitable for babies over a month old);
• Peritol;
• Diazolin;
• Suprastin (suitable for babies);
• Klarotadin;
• Tavegil;
• Tsetrin (suitable for newborns);
• Zyrtec;
• Clarisens;
• Cinnarizine;
• Loratadine;
• Zodak;
• Claritin;
• Erius (allowed from birth);
• Lomilan;
• Fenkarol.

The mechanism of action of antihistamines

Under the influence of an allergen, an excess of histamine is produced in the body. When it is associated with certain receptors, negative reactions are caused (edema, rash, itching, runny nose, conjunctivitis, etc.). Antihistamines reduce the release of this substance into the bloodstream. In addition, they block the action of histamine H1 receptors, thereby preventing them from binding and reacting with histamine itself.

Side effects

Each drug has its own list. The specific list of side effects also depends on which generation the agent belongs to. Here are some of the most common ones:

• headache;
• drowsiness;
• confusion of consciousness;
• decreased muscle tone;
• fast fatiguability;
• constipation;
• concentration disorders;
• blurred vision;
• abdominal pain;
• dizziness;
• dry mouth.

Contraindications

Each antihistamine has its own list, indicated in the instructions. Almost every one of them is forbidden to be taken by pregnant girls and lactating mothers. In addition, the list of contraindications for therapy may include:

• individual intolerance to the components;
• glaucoma;
• stomach or duodenal ulcer;
• prostate adenoma;
• obstruction of the bladder;
• children or old age;
• lower respiratory tract diseases.

The best allergy remedies

TOP 5 most effective drugs:

1. Erius. A fast-acting medicine that well eliminates a runny nose, itching, and rashes. It's expensive.
2. Eden. Preparation with desloratadine. Does not have a hypnotic effect. Copes well with lacrimation, itching, puffiness.
3. Zyrtec. The drug is based on cetirizine. Fast acting and efficient.
4. Zodak. An excellent allergy medicine that instantly relieves symptoms.
5. Cetrin. A drug that rarely gives side effects. Eliminates allergy symptoms quickly.

The price of antihistamines

All medicines are available for purchase, and you can easily choose the most suitable one. Sometimes they give good discounts on funds. You can buy them in pharmacies in Moscow, St. Petersburg and other cities, order their delivery by mail from online pharmacies. For an approximate price range for antihistamines, see the table:

Drug name, release form, volume	Approximate cost in rubles
Suprastin tablets, 20 pcs.
Zyrtec drops, 10 ml
Fenistil drops, 20 ml
Erius, tablets, 10 pcs.
Zodak, tablets, 30 pcs.
Claritin tablets, 30 pcs.
Tavegil, tablets, 10 pcs.
Cetrin, tablets, 20 pcs.
Loratadin tablets, 10 pcs.

Antihistamines (or in simple words, drugs for allergies) belong to a group of drugs whose action is based on blocking histamine, which is the main mediator of inflammation and a provocateur of allergic reactions. As you know, an allergic reaction is the body's immune response to the effects of foreign proteins - allergens. Antihistamines are designed to relieve these symptoms and prevent them from occurring in the future.

In the modern world, antiallergic drugs are widespread, representatives of this group can be found in the medicine cabinet of any family. The pharmaceutical industry expands its range every year and releases more and more new drugs, the action of which is aimed at combating allergies.

Antihistamines of the 1st generation are gradually becoming a thing of the past, they are being replaced by new drugs, which are advantageously distinguished by their ease of use and safety. It can be difficult for an ordinary consumer to understand such a variety of medicines, so in this article we will present the best antihistamines of different generations and talk about their advantages and disadvantages.

The main job of allergy medications is to interfere with the production of histamine, which is produced by the cells of the immune system. Histamine in the body accumulates in mast cells, basophils and platelets. A large number of these cells are concentrated in the skin, mucous membranes of the respiratory system, next to blood vessels and nerve fibers. Under the action of an allergen, histamine is released, which penetrates into the extracellular space and the circulatory system, causing allergic reactions from the most important systems of the body (nervous, respiratory, integumentary).

All antihistamines inhibit the release of histamine and prevent it from attaching to the end of nerve receptors. Medicines in this group have antipruritic, antispastic and decongestant effects, effectively eliminating allergy symptoms.

To date, several generations of antihistamines have been developed, differing from each other in the mechanism of action and the duration of the therapeutic effect. Let us dwell in more detail on the most popular representatives of each generation of antiallergic drugs.

1st generation antihistamines - list

The first drugs with antihistamine action were developed back in 1937 and since then have been widely used in therapeutic practice. Medicines enter into a reversible relationship with H1 receptors, additionally encompassing cholinergic muscarinic receptors.

Medicines of this group have a quick and pronounced therapeutic effect, have an antiemetic and anti-pumping effect, but it does not last long (from 4 to 8 hours). This explains the need for frequent high doses of the drug. 1st generation antihistamines are able to effectively cope with allergy symptoms, but their positive qualities are largely offset by significant disadvantages:

• A distinctive characteristic of all drugs in this group is sedation. Means of the 1st generation are able to penetrate the blood-brain barrier to the brain, causing drowsiness, muscle weakness, and inhibiting the activity of the nervous system.
• Addictiveness quickly develops on the action of drugs, which significantly reduces their effectiveness.
• First generation drugs have quite a few side effects. Taking pills can cause tachycardia, visual impairment, dry mouth, constipation, urinary retention and increase the negative effects of alcohol on the body.
• Due to the sedative effect, the medication should not be taken by persons who drive vehicles, as well as those whose professional activities require a high concentration of attention and speed of reaction.

First generation antihistamines include:

1. Diphenhydramine (from 20 to 110 rubles)
2. Diazolin (from 18 to 60 rubles)
3. Suprastin (from 80 to 150 rubles)
4. Tavegil (from 100 to 130 rubles)
5. Fenkarol (from 95 to 200 rubles)

Diphenhydramine

The drug has a fairly high antihistamine activity, has an antitussive and antiemetic effect. Effective for hay fever, vasomotor rhinitis, urticaria, seasickness, allergic reactions caused by medication.

Diphenhydramine has a local anesthetic effect, so it can be replaced with Lidocaine or Novocaine in case of intolerance.

The disadvantages of the drug include a pronounced sedative effect, the short duration of the therapeutic effect and the ability to cause rather serious side reactions (tachycardia, disturbances in the functioning of the vestibular apparatus).

Diazolin

Indications for use are the same as for Diphenhydramine, but the sedative effect of the drug is much weaker.

However, when taking medication, patients may notice drowsiness and a slowdown in psychomotor reactions. Diazolin can cause side effects: dizziness, irritation of the gastrointestinal mucosa, fluid retention in the body.

Suprastin

It can be used to treat symptoms of urticaria, atopic dermatitis, allergic conjunctivitis, rhinitis, itching. The drug can help with severe complications by warning.

Possesses high antihistaminic activity, has a quick effect, which allows the drug to be used to relieve acute allergic conditions. The disadvantages include the short duration of the therapeutic effect, lethargy, drowsiness, dizziness.

Tavegil

The drug has a longer antihistamine effect (up to 8 hours) and has a less pronounced sedative effect. However, taking the drug may cause dizziness and lethargy. Tavegil in the form of injections is recommended for such serious complications as Quincke's edema and anaphylactic shock.

Fenkarol

It is taken when it is necessary to replace an antihistamine that has lost its effectiveness due to addiction. This drug is less toxic, does not have a depressing effect on the nervous system, but retains weak sedative properties.

Currently, doctors try not to prescribe 1st generation antihistamines due to the abundance of side effects, preferring more modern drugs of 2-3 generations.

2nd generation antihistamines - list

Unlike drugs of the 1st generation, more modern antihistamines do not have a sedative effect, are not able to penetrate the blood-brain barrier and have a depressing effect on the nervous system. The 2nd generation drugs do not reduce physical and mental activity, they have a quick healing effect that lasts a long time (up to 24 hours), which allows you to take just one dose of the drug per day.

Among other advantages, the absence of addiction is distinguished, due to which medicines can be used for a long time. The therapeutic effect of taking medications lasts for 7 days after the drug is discontinued.

The main disadvantage of this group is the cardiotoxic effect, which develops as a result of blocking the potassium channels of the heart muscle. Therefore, drugs of the 2nd generation are not prescribed to patients with cardiovascular problems and elderly patients. In other patients, taking medications should be accompanied by monitoring of cardiac activity.

Here is a list of the most popular 2nd generation antihistamines and their prices:

• Allergodil (Azelastin) - from 250 to 400 rubles.
• Claritin (Loratadin) - price from 40 to 200 rubles.
• Semprex (Aktivastin) - from 100 to 160 rubles.
• Kestin (Ebastin) - from the price of 120 to 240 rubles.
• Fenistil (Dimetinden) - from 140 to 350 rubles.

Claritin (Loratadin)

This is one of the most popular second generation drugs. Differs in high antihistaminic activity, lack of sedative effect. The medicine does not enhance the effects of alcohol, it goes well with other medicines.

The only drug in the group that does not have an adverse effect on the heart. Does not cause addiction, lethargy and drowsiness, which allows you to prescribe Loratadin (Claritin) to drivers. Available in the form of tablets and syrup for children.

Kestin

The drug is used to treat allergic rhinitis, conjunctivitis, urticaria. The advantages of the drug are the absence of sedation, the rapid onset of the therapeutic effect and its duration, which lasts for 48 hours. Of the minuses - side reactions (insomnia, dry mouth, abdominal pain, weakness, headache).

Fenistil(drops, gel) - differs from 1st generation drugs in high antihistaminic activity, duration of therapeutic effect and less pronounced sedative effect.

Semprex- has a minimal sedative effect with pronounced antihistamine activity. The therapeutic effect comes quickly, but in comparison with other drugs in this group, it is more short-lived.

3rd generation - a list of the best drugs

Antihistamines of the 3rd generation act as active metabolites of drugs of the second generation, but unlike them, they do not have a cardiotoxic effect and do not affect the work of the heart muscle. They have practically no sedative effect, which makes it possible to use medications in persons whose activities are associated with increased concentration of attention.

Due to the absence of side effects and negative effects on the nervous system, these drugs are recommended for long-term treatment, for example, with seasonal exacerbations of long-term allergies. The drugs of this group are used in different age categories, for children they produce convenient forms (drops, syrup, suspension), which make it easier to take.

Antihistamines of the new generation are distinguished by their speed and duration of action. The therapeutic effect occurs within 15 minutes after administration and lasts up to 48 hours.

Medicines can cope with the symptoms of chronic allergies, year-round and seasonal rhinitis, conjunctivitis, bronchial asthma, urticaria, dermatitis. They are used to relieve acute allergic reactions, are prescribed as part of the complex treatment of bronchial asthma, dermatological diseases, in particular psoriasis.

The most popular representatives of this group are the following drugs:

• Zyrtek (price from 150 to 250 rubles)
• Zodak (price from 110 to 130 rubles.)
• Tsetrin (from 150 to 200 rubles)
• Cetirizine (from 50 to 80 rubles)

Cetrin (Cetirizine)

This drug is rightfully considered the "gold standard" in the treatment of allergic manifestations. It is successfully used in adults and children to eliminate severe allergies and bronchial asthma.

Cetrin is used for the treatment and prevention of conjunctivitis, allergic rhinitis, pruritus, urticaria, angioedema. After a single dose, relief occurs within 15-20 minutes and continues throughout the day. With the course application, addiction to the drug does not occur, and after the termination of therapy, the therapeutic effect persists for 3 days.

Zyrtek (Zodak)

The drug is able not only to enclose the course of allergic reactions, but also to prevent their occurrence. By reducing capillary permeability, effectively eliminates edema, relieves skin symptoms, relieves itching, allergic rhinitis, inflammation of the conjunctiva.

Taking Zyrtek (Zodak) allows you to stop attacks of bronchial asthma and prevent the development of serious complications (Quincke's edema, anaphylactic shock). At the same time, non-compliance with the dosage can lead to migraines, dizziness, drowsiness.

Antihistamines of the 4th generation are the latest drugs that can have an immediate effect in the absence of side effects. These are modern and safe remedies, the action of which lasts for a long time, without affecting in any way the state of the cardiovascular and nervous system.

Despite the minimum of side effects and contraindications, before you start taking it, you should consult with your doctor, since the latest generation drugs have certain restrictions for use in children and are not recommended for use in pregnant and lactating women.

The list of the latest drugs includes:

• Telfast (Fexofenadine) - price from 180 to 360 rubles.
• Erius (Desloratadin) - from 350 to 450 rubles.
• Ksizal (Levocetirizine) - from 140 to 240 rubles.

Telfast

It is highly effective against pollinosis, urticaria, and prevents acute reactions (Quincke's edema). Due to the absence of a sedative effect, it does not affect the speed of reactions and does not cause drowsiness. If the recommended dosage is observed, it has practically no side effects, when taken in high doses, dizziness, headache, and nausea may occur. High efficiency and duration of action (more than 24 hours) allow you to take only 1 tablet of the drug per day.

Erius

The medicine is produced in the form of film-coated tablets and syrup, intended for children over 12 months of age. The maximum therapeutic effect is achieved 30 minutes after taking the drug and lasts for 24 hours.

Therefore, it is recommended to take only 1 Erius tablet per day. The dosage of the syrup is determined by the doctor and depends on the age and weight of the child. The drug has practically no contraindications (except for the period of pregnancy and lactation) and does not affect the concentration of attention and the state of the vital systems of the body.

Ksizal

The effect of using the drug occurs within 10-15 minutes after taking it and lasts for a long time, and therefore it is enough to take only 1 dose of the drug per day.

The drug effectively eliminates mucosal edema, skin itching and rashes, prevents the development of acute allergic reactions. Ksizal can be treated for a long time (up to 18 months), it is not addictive and has practically no side effects.

Antihistamines of the 4th generation have proven their effectiveness and safety in practice, they are gaining popularity and are available to a wide range of consumers.

Nevertheless, one should not engage in self-medication; before purchasing a drug, it is necessary to consult a doctor who will select the best option, taking into account the severity of the disease and possible contraindications.

Children are much more susceptible to allergic diseases than adults. Antihistamines for children should be effective, have a milder effect and a minimum of contraindications. They should be selected by a qualified specialist - an allergist, since many medications can cause unwanted side reactions.

A child's body, with not yet formed immunity, can react sharply to taking the drug, therefore, a doctor should be observed during the period of treatment of the child. For children, medicines are produced in convenient dosage forms (in the form of syrup, drops, suspension), which facilitates the dosage and does not cause disgust in the child when taken.

Suprastin, Fenistil will help to quickly relieve acute symptoms; for longer treatment, modern drugs Zyrtec or Ketotifen are usually used, which are approved for use from 6 months of age. Of the latest generation drugs, Erius is the most popular, which in the form of a syrup can be prescribed to children from 12 months. Medicines such as Claritin, Diazolin can be used from 2 years old, but the latest generation drugs (Telfast and Ksizal) - only from 6 years old.

The most common drug for the treatment of infants is Suprastin, the doctor prescribes it in the minimum dosage that can have a therapeutic effect and provide a mild sedative and hypnotic effect. Suprastin is completely safe not only for babies, but also for nursing mothers.

Of the more modern drugs to eliminate allergic manifestations in children, Zyrtec and Claritin are most often used. These remedies last longer, so you can take one dose of medication per day.

Allergy medications during pregnancy

Antihistamines during pregnancy should not be taken in the first trimester. Subsequently, they are prescribed only according to indications and taken under the supervision of a doctor, since no medication is completely safe.

Medicines of the last, 4th generation are absolutely contraindicated in any trimester of pregnancy and during breastfeeding. The safest medicines for allergies during pregnancy include Claritin, Suprastin, Zyrtec.