What is the difference between antihistamine and antiallergic? Antihistamines - generations, principles of action, review of drugs
Allergic reactions are divided into immediate, developing immediately after exposure to the antigen, and delayed, appearing after several days or even weeks. At immediate type allergies, antihistamines are most effective. The principle of their action is based on blocking free histamine, which is released in the body in response to a physical or chemical irritant. Having a structure similar to a biogenic amine, the active substance blocks histamine receptors, preventing the amine itself from performing the functions of a mediator of allergic reactions.
There are three generations of antihistamines. Designed in different time, they differ in their selectivity of action. Each of the subsequent pharmaceutical lines is more selective, that is, the active substance of the drug binds predominantly to one type of receptor. This increases the safety of the drug and reduces the risk of side effects.
The first generation was created in 1936, its representatives are Diphenhydramine, Diazolin, Tavegil, Suprastin, Fenkarol. They show good results as histamine blockers: they eliminate allergic manifestations in the form of rashes, swelling, itching. However, all these drugs have a short-term effect (3-4 hours), and with long-term use they reduce their activity, and also give quite a lot of side effects:
- due to low selectivity, they have an undesirable effect on the cellular structures of many organs, and are therefore contraindicated in peptic ulcer, renal, hepatic and cardiovascular pathologies, glaucoma, epilepsy;
- being anticholinergics, they can cause dysfunction of the central nervous system, headache, dizziness, falling blood pressure;
- reduce muscle tone;
- have a hypnotic effect;
- cause an increase in body weight.
Important information!
Due to the pronounced sedative effect antihistamines first generation, if they are used, driving, as well as performing other work that requires increased attention or quick reaction, is possible only 12 hours after taking the medicine.
Second generation drugs - Hexal, Clarisens, Kestin, Claritin, Clarotadine, Lomilan, Zirtec, Rupafin and others - appeared in the 80s of the last century. They act more selectively, affecting mainly histamine receptors, and therefore have fewer side effects.
Another advantage is the lack of addiction and the duration of action is up to 24 hours. This allows you to take the medicine once a day and not increase the dose during long-term use. However, due to the cardiotoxic effect, when taking most of these drugs, constant monitoring of cardiac activity is required, and in patients with serious cardiovascular pathologies, 2nd generation antihistamines are contraindicated.
In recent years, drugs whose active ingredients belong to the category of prodrugs have been successfully used to treat all types of allergies, that is, they are converted into pharmacologically active compounds in the body as a result of metabolic processes. The effectiveness of these products is several times higher than that of their predecessors. They also have high selectivity, and therefore do not produce either sedative or cardiotoxic effects, and, therefore, are the safest.
The list of new generation antihistamines is still relatively small, but they all have a common advantage: they can be taken for diseases of the heart, gastrointestinal tract, kidney and liver pathologies, as well as for people whose work requires a high concentration of attention. Some of the drugs in this group are not contraindicated during pregnancy and childhood.
Comparative characteristics of 3rd generation drugs
Indications for the use of this category of drugs are:
- food allergies;
- seasonal and chronic allergic conjunctivitis and rhinitis;
- hives;
- exudative diathesis;
- contact and atopic dermatitis.
Drugs with the same active ingredient can be produced under different names trademarks(these are so-called synonymous drugs).
Allegra
It is also produced under the names Fexadine, Fexofenadine, Telfast, Fexofast, Tigofast. The active ingredient is fexofenadine hydrochloride. Release form: film-coated tablets of 120 and 180 mg.
The initial effect occurs within an hour after administration, reaches the maximum concentration in the blood after 3 hours, the half-life is about 12 hours, the duration of action is a day. A single dose is 180 mg, the course of treatment is determined individually. Because the clinical researches the effect of fexofenadine on the fetus and children's body have not been carried out, during pregnancy, children under 12 years of age and breastfeeding women, it is prescribed only in cases of special need.
The cost of a drug depends on the content of the main substance and the manufacturer. For example, 10 tablets of 120 mg of Fexadine Ranbaxy (India) cost 220 rubles, the same package of Allegra from Sanofi-Aventis (France) costs 550 rubles, and 10 tablets of 180 mg of Telfast Sanofi-Aventis cost 530 rubles.
Cetirizine
Other trade names: Cetrin, Cetrinal, Parlazin, Zodak, Amertil, Allertek, Zirtek. A substance that is active against histamine is cetirizine dihydrochloride. Available in tablets containing active substance 10 mg, as well as in the form of drops, solutions and syrup.
The initial effect is observed 1 – 1.5 hours after administration, the total duration of action is up to a day, metabolites are excreted within 10-15 hours in the urine. Single (and daily) dose of 10 mg. The drug is not addictive and can be used for long-term therapy. It is not recommended for children under 1 year of age and pregnant women to take it.
Approximate cost of cetirizine and its analogues:
- Cetirizine, manufacturer Vertex, Russia (10 tablets) – 66 rubles;
- Tsetrin, manufacturer Dr. Reddy, India (20 tables) – 160 rubles;
- Zodak, manufacturer Zentiva, Czech Republic (10 tablets) – 140 rubles;
- Zirtek, manufacturer USB Farshim, Belgium (drops in 10 ml bottles) – 320 rubles.
Xizal
Synonyms: Suprastinex, Levocetirizine, Glencet, Zilola, Alerzin. Active ingredient: Levocetirizine dihydrochloride. The medicine is available in 5 mg tablets and drops; the dosage form for children is syrup.
The affinity for histamine receptors of this drug is several times higher than that of other representatives of this series, so its effect lasts for 2 days. Metabolic products are excreted by the kidneys; the half-life is 8–10 hours. The daily dose for adults and children over 6 years of age is 5 mg. Contraindications to the use of levocetirizine are congenital disorders carbohydrate metabolism.
Estimated cost of drugs:
- Xyzal, manufacturer USB Farshim, Belgium (drops in 10 ml bottles) – 440 rubles;
- Levocetirizine, manufacturer Teva, France (10 tablets) – 270 rubles;
- Alerzin, manufacturer Eric, Hungary (14 tables) – 300 rubles;
- Suprastinex, manufacturer Eric, Hungary (7 tables) – 150 rubles.
Desloratadine
Other trade names: Erius, Dezal, Allergostop, Fribris, Alersis, Lordestin. The bioactive substance is desloratadine. Release forms: film-coated tablets of 5 mg, solution containing active substance 5 mg/ml and syrup.
The maximum concentration in the blood is observed after 3–4 hours, the half-life is 20–30 hours, the total duration of action is 24 hours. A single dose for adults and children over 12 years of age is 5 mg; the dosage for children from 2 to 12 years of age is determined individually. For pregnant and lactating women, the drug is prescribed for life-threatening conditions.
Cost of desloratadine and its synonyms:
- Desloratadine, manufacturer Vertex, Russia (10 tablets) – 145 rubles;
- Lordestin, Bayer, USA, manufacturer Gedeon Richter, Hungary (10 tablets) – 340 rubles;
- Erius, manufacturer Bayer, USA (7 tablets) – 90 rubles.
All antiallergic drugs are prescribed by a doctor, taking into account the specifics of their action, the causes of allergies, the age and characteristics of the patient’s body. When taking antihistamines, you should strictly adhere to the rules specified in the instructions.
New generation antihistamines are the most effective drugs in the treatment of allergies
Medicines that block histamine receptors in the body and thereby inhibit the effects they cause are called antihistamines.
What is histamine
Histamine is a mediator that, during allergic reactions, is released from connective tissue and has a negative effect on the organs and systems of the body: skin, Airways, cardiovascular system, digestive tract and others.
Antihistamines are used to suppress free histamine and are divided into 3 groups depending on the receptors they block:
- H1 blockers - this group of drugs is used in the treatment of allergic diseases.
- H2 blockers - indicated for stomach diseases, as they have a positive effect on its secretion.
- H3 blockers - used in the treatment of neurological diseases.
Currently, there are many antihistamines:
- Diphenhydramine
- Diazolin
- Suprastin
- Claritin
- Kestin
- Rupafin
- Loragexal
- Zyrtec
- Telfast
- Erius
- Zodak
- Parlazin
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They are divided into three generations of drugs for the treatment of allergic diseases.
- The first generation of antihistamines, called classical, includes:
- diphenhydramine
- diazolin
- suprastin
- fenkarol
- tavegil
The mechanism of their action is a reversible connection with peripheral and central H1 receptors, which blocks various effects histamine: increased vascular permeability, contraction of bronchial and intestinal muscles. They quickly cross the blood-brain barrier, while contacting brain receptors, hence the powerful sedative and hypnotic effect.
Pros: These drugs act quickly and strongly - within half an hour a reduction in allergic symptoms is achieved. They also have an anti-sickness and anti-emetic effect, and reduce elements of parkinsonism. They have anticholinergic and local anesthetic effects. They are quickly eliminated from the body.
Cons of antihistamines are short-lived therapeutic effect(4-6 hours), the need to change the drug during long-term therapy due to a decrease in its therapeutic activity and a wide range of side effects, such as drowsiness, blurred vision, dry mouth, constipation, headache, urinary retention, tachycardia and lack of appetite. They do not have any additional antiallergic effect. Interact with other drugs.
Drugs in this group are well suited for quickly achieving an effect when it is necessary to treat acute allergic manifestations, for example, urticaria, seasonal rhinitis or an allergic reaction to food.
The second generation of antihistamines, or H1 antagonists, which entered the market at the end of the 70s of the last century, are structurally related to H1 receptors, therefore they do not have the range of side effects characteristic of 1st generation drugs and they have a much wider range of applications.
These include:
- Clarisens
- Claridol
- Lomilan
- Claritin
- kestin
- rupafin
- lorahexal
Their mechanism of action is carried out through the accumulation of active antihistamine metabolites in the blood in a sufficient and long-lasting concentration. The active ingredients do not cross the blood-brain barrier, acting on the mast cell membrane, so the risk of drowsiness is minimized.
- physical and mental activity doesn't subside
- The duration of exposure is up to 24 hours, so taking most drugs once a day is enough
- when treatment is stopped, the therapeutic effect lasts a week
- not addictive
- active ingredients are not adsorbed in the gastrointestinal tract
- have a cardiotoxic effect because they block potassium channels of the heart;
long lasting therapeutic effect
negative effect on the liver and heart
2nd generation antihistamines are used to relieve acute and long-term allergic diseases, mild bronchial asthma, and chronic idiopathic urticaria. Contraindicated for elderly people, patients with cardiovascular problems and kidney and liver diseases. Requires constant monitoring of cardiac activity.
- Zyrtec (cetirizine)
- Telfast (fexofenadine)
- Trexyl (terfenadine)
- hismanal (astemizole)
- Erius (desloratadine)
- Semprex (crivastin)
- allergodil (acelastine)
Improved modern drugs have a significant duration of action - from half to two days, after completion of treatment they have an inhibitory effect on histamine for 6-8 weeks.
- have no systemic significant side effects
- indicated for all age groups - some of them are classified as over-the-counter drugs
- suitable for activities requiring high concentration of attention
- indicated for the prevention of allergic diseases
- not addictive
- do not, with rare exceptions, have significant drug interactions
For Trexyl (terfenadine) and astimizan (astemizole), cases of serious cardiotoxic side effects have been described.
if the drugs are used incorrectly, dizziness, nausea, skin flushing, and gastrointestinal reactions are possible;
Individuals with renal and hepatic problems should be selective about drugs in this group.
The use of the latest generation of antihistamines is justified for all groups of the population without exception during long-term treatment of allergic diseases - atopic dermatitis, year-round allergic rhinitis, atopic syndrome, chronic urticaria, contact dermatitis and others.
The best antihistamines today are Zyrtec (cetirizine) and Claritin (loratadine). The safe profiles of these medications are ideal for all age groups, especially children, as they reduce the risk of progression of allergic manifestations in the future.
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I finally found the answer to a question that has been bothering me for a long time.
I have long noticed that during exacerbations of seasonal allergies, all these expensive and sophisticated antihistamines of the latest generation, which can be taken only once every 24 or even 48 hours, for some reason help me much worse than the budget diazolin. I thought that it was a matter of individual characteristics of the body, but it turned out that several friends had the same situation. It turns out that first-generation drugs provide better relief acute attacks, and the latest generation of drugs are more suitable for the treatment of chronic allergies? But even during a period of short-term allergies, you don’t really want to drink handfuls of pills and nod off at work... Well, this is another confirmation of the truism that you need to contact a specialist for a competent prescription.
I’ve been using Claritin as an antihistamine all my life, and I’m completely satisfied with it - it relieves symptoms quickly, doesn’t make me sleepy, I drink it calmly while driving. Of course, there are now more fashionable and new means, for example, zodak, but I am somehow inclined to trust a time-tested remedy, and why change something that already helps? In general, of course, first of all it is necessary to identify the allergen itself, and, based on this, build a treatment regimen, and it is better, of course, after consulting with a specialist...
Our magazine contains the most complete information on dermatological diseases. We especially pay attention to symptoms, causes and treatment.
The most effective antihistamines for children and adults - a list of medications with instructions and prices
A small number of people are lucky enough to never experience an allergic reaction in their lives. Most people have to deal with them periodically. Effective antihistamines will help both adults and children cope with allergies. Such remedies help eliminate negative reactions on the body to certain stimuli. There is a wide range of anti-allergy medications on the market. It is desirable for every person to be able to understand them.
What are antihistamines
These are medications that work to suppress the action of free histamine. This substance is released from connective tissue cells that are part of the immune system when any allergen enters the human body. When histamine interacts with certain receptors, swelling, itching, and rashes begin. All these are symptoms of allergies. Drugs with antihistamine effect block the above-mentioned receptors, alleviating the patient’s condition.
Indications for use
A doctor must prescribe antihistamines to you after making an accurate diagnosis. As a rule, their use is advisable in the presence of the following symptoms and diseases:
- early atopic syndrome in a child;
- seasonal or year-round 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 antiallergic drugs. Their classification:
- New generation drugs. The most modern medicines. They act very quickly, and the effect of their use lasts for a long time. They block H1 receptors, suppressing allergy symptoms. Antihistamines in this group do not worsen heart function, therefore they are considered one of the safest.
- 3rd generation drugs. Active metabolites with very few contraindications. They provide quick, lasting results and are gentle on the heart.
- 2nd generation drugs. Non-sedative medications. They have a small list side effects, put a lot of stress on the heart. Do not affect mental or physical activity. Second-generation antiallergic drugs are often prescribed for the appearance of rash and itching.
- 1st generation drugs. Sedative medications, lasting up to several hours. They eliminate allergy symptoms well, but have many side effects and contraindications. Eating them always makes you sleepy. Nowadays, such drugs are prescribed very rarely.
New generation antiallergic drugs
It is not possible to list all the drugs in this group. It's worth taking a look at a few of the best ones. The following drug opens this list:
- name: Fexofenadine (analogues - Allegra (Telfast), Fexofast, Tigofast, Altiva, Fexofen-Sanovel, Kestin, Norastemizole);
- action: blocks H1 -histamine receptors, relieves all allergy symptoms;
- advantages: it acts quickly and for a long time, is available in tablets and suspensions, is well tolerated by patients, does not have too many side effects, is available without a prescription;
- cons: not suitable for children under six years of age, pregnant women, nursing mothers, incompatible with antibiotics.
Another drug worthy of attention:
- name: Levocetirizine (analogs - Aleron, Zilola, Alerzin, Glencet, Aleron Neo, Rupafin);
- action: antihistamine, blocks H1 receptors, reduces vascular permeability, has antipruritic and antiexudative effects;
- pros: there are tablets, drops, syrup on sale, the drug works in just a quarter of an hour, there are not many contraindications, it is compatible with many medications;
- cons: a wide range of strong side effects.
- name: Desloratadine (analogs - Lordes, Allergostop, Alersis, Fribris, Eden, Eridez, Alergomax, Erius);
- action: antihistamine, antipruritic, decongestant, relieves rashes, runny nose, nasal congestion, reduces bronchial hyperactivity;
- pros: the new generation 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, can be taken together with other drugs;
- cons: not suitable for pregnancy and lactation, prohibited for children under 12 years of age.
Antihistamines 3 generations
The following drug is popular and has many good reviews:
- name: Dezal (analogues – Ezlor, Nalorius, Elisey);
- action: antihistamine, relieves swelling and spasms, relieves itching, rashes, allergic rhinitis;
- pros: available in tablets and solution, does not give a sedative effect and does not affect the speed of reactions, works quickly and lasts for about a day, is quickly absorbed;
- cons: bad for the heart, many side effects.
Experts respond well to this drug:
- name: Suprastinex;
- action: antihistamine, prevents the appearance of allergic manifestations and facilitates their course, helps with itching, peeling, sneezing, swelling, rhinitis, lacrimation;
- pros: available in drops and tablets, there is no sedative, anticholinergic or 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: Xyzal;
- action: pronounced antihistamine, not only relieves allergy symptoms, but also prevents their occurrence, reduces the permeability of vascular walls, fights sneezing, lacrimation, swelling, urticaria, inflammation of the mucous membranes;
- pros: sold in tablets and drops, does not have a sedative effect, is well absorbed;
- cons: has a wide list of side effects.
Antiallergenic drugs 2nd generation
A well-known series of medications is represented by tablets, drops, syrups:
- name: Zodak;
- action: prolonged antiallergic, helps against itching, flaking of the skin, relieves swelling;
- pros: if the dosage and rules of administration are followed, it does not cause drowsiness, begins to act quickly, and is not addictive;
- cons: prohibited for pregnant women and children.
The following second generation drug:
- name: Cetrin;
- action: antihistamine, good for swelling, hyperemia, itching, peeling, rhinitis, urticaria, reduces capillary permeability, relieves spasms;
- pros: drops and syrup are available for sale, low cost, lack of anticholinergic and antiserotonin effects, if the dosage is observed, does not affect concentration, is not addictive, side effects are extremely rare;
- cons: there are a number of strict contraindications; an overdose is very dangerous.
Another very good drug this category:
- name: Lomilan;
- action: systemic blocker of H1 receptors, relieves all allergy symptoms: itching, peeling, swelling;
- pros: does not affect the heart and central nervous system, is completely eliminated from the body, helps to overcome allergies well and quickly, suitable for continuous use;
- cons: many contraindications and side effects.
1st generation products
Antihistamines in this group appeared a long time ago and are now used less frequently than others, but nevertheless deserve attention. Here is one of the most famous:
- name: Diazolin;
- action: antihistamine, H1 receptor blocker;
- pros: gives anesthetic effect, acts for a long time, helps well with dermatoses with itchy skin, rhinitis, cough, food and drug allergies, insect bites, is cheap;
- disadvantages: there is a moderately pronounced sedative effect, many side effects, contraindications.
This one also belongs to 1st generation drugs:
- name: Suprastin;
- action: antiallergic;
- pros: available in tablets and ampoules;
- cons: pronounced sedative effect, the effect does not last long, there are a lot of contraindications and side effects.
The last representative of this group:
- name: Fenistil;
- action: histamine blocker, antipruritic;
- pros: available in the form of a gel, emulsion, drops, tablets, relieves skin irritation well, provides some pain relief, inexpensive;
- cons: the effect after use wears off quickly.
Allergy tablets for children
Most antihistamines have strict contraindications based on age. It would be quite reasonable to ask: how to treat very young allergy sufferers, who suffer no less than adults? As a rule, children are prescribed drugs in the form of drops, suspensions, and not tablets. Medicines approved for the treatment of infants and persons under 12 years of age:
- Diphenhydramine;
- Fenistil (drops are suitable for babies older than a month);
- Peritol;
- Diazolin;
- Suprastin (suitable for infants);
- Clarotadine;
- Tavegil;
- Cetrin (suitable for newborns);
- Zyrtec;
- Clarisens;
- Cinnarizine;
- Loratadine;
- Zodak;
- Claritin;
- Erius (allowed from birth);
- Lomilan;
- Fenkarol.
Mechanism of action of antihistamines
Under the influence of an allergen, the body produces excess histamine. When it binds to certain receptors, negative reactions are caused (swelling, rash, itching, runny nose, conjunctivitis, etc.). Antihistamines reduce the release of this substance into the blood. In addition, they block the action of H1-histamine 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 product belongs to. Here are a few of the most common:
- headache;
- drowsiness;
- confusion;
- decreased muscle tone;
- fast fatiguability;
- constipation;
- disturbances in concentration;
- blurred vision;
- abdominal pain;
- dizziness;
- dry mouth.
Contraindications
Each antihistamine has its own list indicated in the instructions. Almost every one of them is prohibited for pregnant girls and nursing mothers. In addition, the list of contraindications for therapy may include:
- individual intolerance to components;
- glaucoma;
- stomach or duodenal ulcer;
- prostate adenoma;
- bladder obstruction;
- children or old age;
- lower respiratory tract diseases.
The best allergy remedies
TOP 5 most effective drugs:
- Erius. Fast acting medicine, good for eliminating runny nose, itching, rashes. It costs expensive.
- Eden. A drug containing desloratadine. Does not have a hypnotic effect. Copes well with lacrimation, itching, swelling.
- Zyrtec. A drug based on cetirizine. Fast-acting and effective.
- Zodak. Great medicine for allergies, instantly eliminating symptoms.
- Cetrin. A drug that very rarely produces side effects. Quickly eliminates allergy symptoms.
Price of antihistamines
Name of medicine, 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.
Loratadine, tablets, 10 pcs.
Video: Antiallergic drugs for children
Margarita, 28 years old
Since childhood, spring has been a terrible time for me. I just tried not to leave the house; there wasn’t a single photo of me on the street. When I got tired of this, I turned to an allergist. He prescribed me the drug Cetrin. Taking it, I walked calmly, without reacting to flowering plants, other irritants. There were no side effects from the drug.
Christina, 32 years old
I am allergic to household and other types of dust. The house is perfectly clean, but on the street or at a party only medications can save you. At first I took Erius, but the price of this antihistamine is steep. I replaced it with Desloratadine. It works the same, but costs much less. This medicine helps me very well, one tablet lasts for a day.
The information presented in the article is for informational purposes only. The materials in the article do not encourage self-treatment. Only a qualified doctor can make a diagnosis and give treatment recommendations based on individual characteristics specific patient.
4th generation anti-allergy medications
4th generation antihistamines are the latest tools aimed at enhancing the effectiveness of the fight against allergies. Their distinctive feature
is the duration of the therapeutic effect and the minimum of side effects.
What is histamine?
Histamine is a complex organic substance that is part of many tissues and cells. It is found in special mast cells - histiocytes. This is the so-called passive histamine. IN special conditions
- passive histamine turns into an active state. Released into the blood, it spreads throughout the body and has a negative effect on it. This transition occurs under the influence of:
- traumatic injuries;
- stress;;
- infectious diseases
- effects of medications;
- malignant and benign neoplasms;
- chronic diseases;
removal of organs or their parts.
Active histamine can enter the body with both food and water. Most often this happens when eating food of animal origin that is not fresh.
How does the body react to the appearance of free histamine?
The transition of histamine from a bound state to a free one creates a viral effect.
- For this reason, flu and allergy symptoms are often similar. In this case, the following processes occur in the body:
- Smooth muscle spasms. Most often they occur in the bronchi and intestines.
- Adrenaline rush. This entails increased blood pressure and increased heart rate. Increased output digestive enzymes
- and mucus in the bronchi and nasal cavity.
- Constriction of large and dilation of small blood vessels. This causes swelling of the mucous membrane, redness of the skin, the appearance of a rash, and a sharp decrease in pressure.
The development of anaphylactic shock, which is accompanied by convulsions, loss of consciousness, vomiting, and a sharp drop in pressure.
Antihistamines and their effects
The most effective way to combat histamine are special drugs that reduce the level of this substance in its free active state. Since the first ones were developed medications combat allergies, four generations of antihistamines have been released. In connection with the development of chemistry, biology and pharmacology, these drugs were improved, their effect intensified, and contraindications and undesirable consequences
decreased.
Representatives of antihistamines of all generations
- First generation: Diphenhydramine, Diazolin, Mebhydrolin, Promethazine, Chloropyramine, Tavegil, Diphenhydramine, Suprastin, Peritol, Pipolfen, Fenkarol. All these drugs have a strong sedative and even hypnotic effect. The main mechanism of their action is blocking H1 receptors. Their duration of action ranges from 4 to 5 hours. The antiallergic effect of these drugs can be called good. However, they have too much impact on the entire body. Side effects of such drugs are: dilated pupils, dry mouth, blurred vision, constant drowsiness, weakness.
- Second generation: Doxylamine, Hifenadine, Clemastine, Cyproheptadine, Claritin, Zodak, Fenistil, Gistalong, Semprex. At this stage of pharmaceutical development, drugs appeared that did not have a sedative effect. In addition, they no longer contain the same side effects. They do not have an inhibitory effect on the psyche, and also do not cause drowsiness. They are accepted not only for allergic manifestations from the respiratory system, but also with skin reactions, for example, urticaria. The disadvantage of these drugs was the cardiotoxic effect of their ingredients.
- Third generation: Acrivastine, Astemizole, Dimetindene. These drugs have improved antihistamine capabilities and a small number of contraindications and side effects. Based on the totality of all their properties, they are no less effective than 4th generation drugs.
- Fourth generation: Cetirizine, Desloratadine, Fenspiride, Fexofenadine, Loratadine, Azelastine, Xyzal, Ebastine. 4th generation antihistamines are capable of blocking H1 and H2 histamine receptors. This reduces the body's reactions to the mediator histamine. As a result, the allergic reaction weakens or does not appear at all. The likelihood of bronchospasms is also reduced.
The best of the latest generation
The best 4th generation antihistamines are characterized by a long-lasting therapeutic effect and a low number of side effects. They do not suppress the psyche and do not destroy the heart.
- Fexofenadine is very popular. It is characterized by versatility of action, due to which it can be used for all types of allergies. However, it is prohibited for use by children under 6 years of age.
- Cetirizine is more suitable for the treatment of allergies that manifest themselves on the skin. It is especially recommended for urticaria. The effect of Cetirizine appears 2 hours after administration, but the therapeutic effect lasts all day. So for moderate allergy attacks it can be taken once a day. The drug is often recommended for the treatment of childhood allergies. Long-term use of Cetirizine in children suffering from early atopic syndrome significantly reduces the further negative development of diseases of allergic origin.
- Loratadine has a particularly significant therapeutic effect. This fourth generation drug can rightfully top the list of leaders.
- Xyzal effectively blocks the release of inflammatory mediators, which allows you to get rid of allergic reactions for a long time. It is better to use it for bronchial asthma and seasonal pollen allergies.
- Desloratadine can be considered one of the most popular antihistamines, designed for all age groups. At the same time, it is rightfully considered one of the safest, with almost no contraindications or undesirable effects. However, it is characterized by at least a small, but still sedative effect. However, this effect is so small that it practically does not affect the speed of a person’s reaction and the activity of the heart.
- Desloratadine is most often prescribed to patients with pollen allergies. It can be used both seasonally, that is, during the period of maximum risk, and during other periods. This drug can be successfully used in the treatment of conjunctivitis and allergic rhinitis.
- The drug Levocetirizine, also known under the names Suprastinex and Cesera, is considered an excellent remedy for pollen allergies. In addition, these medications can be used for conjunctivitis and allergic rhinitis.
Thus, fourth-generation antihistamines can be used while driving and performing other tasks that require a good reaction. They usually do not interact with other medications, including antibiotics. This allows them to be taken in the treatment of inflammatory diseases.
Because these drugs do not affect behavior or thought processes and do not have a detrimental effect on cardiac activity, they are usually well tolerated by patients.
In addition, they usually do not interact synergistically with other medications.
If you notice redness, rashes and swelling of the skin, then you need to contact an allergist so that he can prescribe you antihistamines for skin allergies.
An allergy is an increased reaction of our body to certain environmental factors: medications, pollen, household chemicals, dust and others.
Clinical picture
WHAT DOCTORS SAY ABOUT EFFECTIVE METHODS OF TREATING ALLERGIES
Vice-President of the Association of Children's Allergists and Immunologists of Russia. Pediatrician, allergist-immunologist. Smolkin Yuri Solomonovich
Practical medical experience: more than 30 years
According to the latest WHO data, it is allergic reactions in the human body lead to the emergence of most fatal diseases. And it all starts with the fact that a person has an itchy nose, sneezing, runny nose, red spots on the skin, and in some cases, suffocation. 7 million people die every year due to allergies , and the scale of the damage is such that the allergic enzyme is present in almost every person. Unfortunately, in Russia and the CIS countries, pharmaceutical corporations sell expensive medications that only relieve symptoms, thereby hooking people on one drug or another. This is why in these countries there is such a high percentage of diseases and so many people suffer from “non-working” drugs. |
This reaction manifests itself as itching of the skin, redness, rash and swelling, conjunctivitis of the eyes, lacrimation, allergic rhinitis and cough.
Skin rashes on the arms, legs, body and face are well treated with many antihistamines for skin allergies, cheap domestic ones and expensive imported ones.
Allergic dermatosis(skin reaction) is most often treated with drugs in tablets, because external manifestations on the skin are provoked by internal changes.
In this article, we will look at which antihistamine is better, which modern medicine against skin rashes helps well and will not cause severe side effects, and we will find out a list of inexpensive analogues and generics.
Signs of skin allergies
The main causes that cause allergic skin rashes are:
IMPORTANT! If the reason skin rashes not eliminated, then effective treatment is impossible in principle. For example, in case of food allergies, you need to remove those foods that provoke an increased reaction in the body. If you do not identify the cause and do not get rid of it, then even increasing the dose of anti-allergy medication will not be able to cope with the symptoms.
If the symptoms manifest themselves clearly, then you need to take a good antiallergic drug that works comprehensively on all symptoms, and not just on the skin.
List of antihistamines for skin allergies
If you have a skin reaction to an allergen, then you cannot independently compile a list and prices of medications in alphabetical order that help with allergic rashes and which you should try on yourself. You should contact specialists.
At an appointment with an allergist or dermatologist, patients ask: “Please advise which antiallergic medications to take? Tell me the names of effective antiallergic drugs for itchy skin?”
The doctor will not recommend the first thing he comes across; he can help an allergy sufferer when he conducts a comprehensive examination.
The doctor is obliged to talk with the allergy sufferer, find out about other diseases, intolerance to drugs, and be sure to conduct an examination to determine the cause of the disease.
Only after this can the doctor tell you the name of the antihistamine that can help in the treatment of skin allergies, the most powerful in a particular case.
Despite the fact that allergic dermatosis manifests itself externally, it is necessary to treat it from the inside.
Why is this important to know? Because you need to choose the right dosage form of the drug, that is, use primarily not external medications (cream, ointment), but drugs in the form of tablets, drops and solutions.
The choice of medications for skin allergies today is huge: there are good Russian medicines, known since Soviet times, as well as modern anti-allergy drugs that do not cause drowsiness.
All antihistamines interfere with the production of histamine and block the development process the following symptoms: redness, itching, swelling of the skin, and also bring the patient’s blood pressure and breathing back to normal: block spasms in the bronchi and swelling of the larynx. Sign strong remedy There is also a reduction in lacrimation and redness of the whites of the eyes and eyelids, the disappearance of allergic cough and runny nose.
1st generation antihistamines
The first generation of antihistamines are very rarely prescribed nowadays. They have a number common features: medications are inexpensive, but cause side effects that seriously affect the allergy sufferer’s body and his lifestyle.
Common features of this group of antihistamines:
- Low cost (the main price tag most often does not exceed 300 rubles);
- A short-term effect (you need to drink them several times in one day) and quick addiction (they need to be alternated with other medications from this group every couple of weeks).
Symptoms of using first generation antihistamines:
All these side effects complicate the patient’s existing lifestyle and daily routine. These antihistamines can make a person less mobile.
Antihistamine drugs from this group are not popular, except for Suprastin, a cheap drug from the list of essential drugs, established by law as vital. It is better to take these drugs for adults, as they have less side effects. Let's look at them in a table that shows their differences.
| Name | Active substance | Features of the drug | Average price, rub |
| Suprastin | Chloropyramine | Does not cause serious cardiac toxicity | 128 |
| Tavegil | Clemastine | Have serious allergic reactions to components | 159 |
| Diphenhydramine | Diphenhydramine | Strong effect on the central nervous system | 75 |
| Diazolin | Mebhydrolin | Negative effect on the gastrointestinal tract | 69 |
| Peritol | Cyproheptadine | Increases appetite, appearance of photosensitivity | 2400 |
| Pipolfen | Promethazine | Reduced intestinal motility, for children from 2 months | 277 |
| Diprazine | Promethazine | Active effect on the nervous system | 1100 |
| Fenkarol | Hifenadine | Weak efficiency | 350 |
We do not recommend taking these antihistamines due to the huge number of contraindications and serious side effects, but you need to know what they are called.
Antihistamines 2nd generation
For allergic rashes, they often take second-generation antiallergic drugs; they are universal (prescribed for many types of allergies). They are not addictive, do not affect the nervous system, which means there will be no drowsiness or lethargy.
| Name | Active substance | Features of the drug | Average price, rub. |
| Claritin | Loratadine | It is prescribed to children over the age of one year and the elderly, there are almost no side effects. | 174 |
| Semprex | Akrivastine | Has a short duration of action, but the medicine is safe | 110 |
| Trexil | Terfenadine | The first drug of the 2nd generation, depresses the cardiac system. It's inexpensive. | 97 |
| Fenistil | Dimetindene maleate | Tablets, gel. Popular remedy. | 319 |
| Gistalong | Astemizole | Effective for chronic allergies. | No information, because it has not been present on the market for a long time |
Claritin is most often prescribed from this list, because it is believed that this drug is safe. But it can be replaced with domestic inexpensive analogue with a similar active substance, which gave it its trade name (“Loratadine”). The price of the latter is much lower. Loratadine is used in the treatment of children, replacing the first generation drug Ketotifen, which is inexpensive but has a large number of side effects.
- Lycopid.
- Viferon.
- Derinat.
- Timolin.
- Immunofan.
The antihistamines listed above are not all anti-allergy drugs presented on pharmacy shelves. Their huge variety, which is very difficult to understand. The main thing to remember is that a specialist should prescribe this or that drug.
Catad_tema Allergology - articles
Antihistamines: myths and reality
"EFFECTIVE PHARMACOTHERAPY"; No. 5; 2014; pp. 50-56.
T.G. Fedoskova
State Scientific Center Institute of Immunology FMBA of Russia, Moscow
The main drugs that affect the symptoms of inflammation and control the course of diseases of allergic and non-allergic origin include antihistamines.
The article analyzes controversial points regarding the experience of using modern antihistamines, as well as some of their main characteristics. This will allow a differentiated approach to the selection of the optimal drug when carrying out complex therapy for various diseases.
Keywords: antihistamines, allergic diseases, cetirizine, Cetrin
ANTIHISTAMINES: MYTHS AND REALITY
T.G. Fedoskova
State Science Center Institute of Immunology, Federal Medical and Biological Agency, Moscow
Antihistamines belong to main drugs influencing symptoms of inflammation and controlling course of both allergic and non-allergic diseases. In this paper debateable issues experience regarding using current antihistamines as well as some of their characteristics are analyzed. It may let to make a differential choice to administer appropriate drugs for a combination therapy of different diseases.
Key words: antihistamines, allergic diseases, cetirizine, Cetrine
Type 1 antihistamines (H 1 -AGP), or type 1 histamine receptor antagonists, are widely and successfully used in clinical practice for more than 70 years. They are used as part of symptomatic and basic therapy of allergic and pseudoallergic reactions, complex treatment of acute and chronic infectious diseases of various origins, as premedication during invasive and radiocontrast studies, surgical interventions, to prevent side effects of vaccination, etc. In other words, H 1 -AGP is advisable to use in conditions caused by the release of active inflammatory mediators of a specific and nonspecific nature, the main of which is histamine.
Histamine has a wide spectrum biological activity, realized by activation of cell surface specific receptors. The main depot of histamine in tissues is mast cells, and in the blood - basophils. It is also present in platelets, gastric mucosa, endothelial cells and neurons in the brain. Histamine has a pronounced hypotensive effect and is an important biochemical mediator for all clinical symptoms of inflammation of various origins. That is why antagonists of this mediator remain the most popular pharmacological agents.
In 1966, the heterogeneity of histamine receptors was proven. Currently, 4 types of histamine receptors are known - H1, H2, H3, H4, belonging to the superfamily of G-protein-coupled receptors (GPCRs). Stimulation of H1 receptors leads to the release of histamine and the implementation of symptoms of inflammation, mainly of allergic origin. Activation of H2 receptors promotes increased secretion gastric juice and its acidity. H3 receptors are present predominantly in the organs of the central nervous system (CNS). They function as histamine-sensitive presynaptic receptors in the brain, regulate the synthesis of histamine from presynaptic nerve endings. Recently, a new class of histamine receptors, expressed predominantly on monocytes and granulocytes, was identified - H4. These receptors are present in the bone marrow, thymus, spleen, lungs, liver, and intestines. The mechanism of action of H 1 -AGP is based on the reversible competitive inhibition of histamine H 1 receptors: they prevent or minimize inflammatory reactions, preventing the development of histamine-induced effects, and their effectiveness is due to the ability to competitively inhibit the effect of histamine on the loci of specific H 1 receptor zones in effector tissue structures.
Currently, over 150 types of antihistamines are registered in Russia. These are not only H 1 -AGP, but also drugs that increase the ability of blood serum to bind histamine, as well as drugs that inhibit the release of histamine from mast cells. Due to the variety of antihistamines, choose between them for their most effective and rational use in specific clinical cases it is quite difficult. In this regard, controversial points arise, and often myths arise about the use of H 1 -AGP, widely used in clinical practice. The domestic literature contains many works on this topic, but there is no consensus on the clinical use of these drugs.
The myth about three generations of antihistamines
Many people are mistaken in thinking that there are three generations of antihistamines. Some pharmaceutical companies are introducing new drugs that have appeared on pharmaceutical market, as AGP of the third - newest - generation. They tried to include metabolites and stereoisomers of modern AGPs into the third generation. Currently, it is believed that these drugs are second-generation AGPs, since there is no significant difference between them and previous second-generation drugs. According to the Consensus on Antihistamines, it was decided to reserve the name “third generation” to refer to antihistamines synthesized in the future, which will most likely differ from known compounds in a number of basic characteristics.
There are many differences between first and second generation AGPs. This is primarily the presence or absence of a sedative effect. Sedative effect when taking first-generation antihypertensive drugs, it is subjectively noted by 40-80% of patients. Its absence in individual patients does not exclude an objective negative effect of these drugs on cognitive functions, of which patients may not complain (ability to drive, learn, etc.). Dysfunction of the central nervous system is observed even when using minimal doses of these drugs. The effect of first-generation antihypertensive drugs on the central nervous system is the same as when using alcohol and sedatives(benzodiazepines, etc.).
Second-generation drugs practically do not penetrate the blood-brain barrier, and therefore do not reduce the mental and physical activity of patients. In addition, AGPs of the first and second generations differ in the presence or absence of side effects associated with stimulation of receptors of a different type, duration of action, and development of addiction.
The first AGPs - phenbenzamine (Antergan), pyrilamine maleate (Neo-Antergan) began to be used back in 1942. Subsequently, new antihypertensive drugs have emerged for use in clinical practice. Until the 1970s Dozens of compounds belonging to drugs of this group were synthesized.
On the one hand, a large amount has been accumulated clinical experience use of first-generation antihypertensive drugs; on the other hand, these drugs have not been tested in clinical studies appropriate modern requirements evidence-based medicine.
Comparative characteristics AGP of the first and second generations is presented in table. 1 .
Table 1.
Comparative characteristics of AGP of the first and second generations
| Properties | First generation | Second generation |
| Sedation and effects on cognitive function | Yes (in minimal doses) | No in therapeutic doses) |
| Selectivity for H1 receptors | No | Yes |
| Pharmacokinetic studies | Few | A lot of |
| Pharmacodynamic studies | Few | A lot of |
| Scientific research different doses | No | Yes |
| Studies in newborns, children, elderly patients | No | Yes |
| Use in pregnant women | FDA category B (diphenhydramine, chlorpheniramine), category C (hydroxyzine, ketotifen) | FDA category B (loratadine, cetirizine, levocetirizine), category C (desloratadine, azelastine, fexofenadine, olopatadine) |
Note. FDA (US Food and Drug Administration) - Food and Drug Administration (USA). Category B - no teratogenic effect of the drug has been detected. Category C - no studies have been conducted.
Since 1977, the pharmaceutical market has been replenished with new H 1 -AGPs, which have clear advantages over first-generation drugs and meet modern requirements for AGPs set out in the EAACI (European Academy of Allergology and Clinical Immunology) consensus documents.
The myth about the benefits of the sedative effect of first-generation antihypertensive drugs
Even regarding a number of side effects of first-generation antihypertensive drugs, there are misconceptions. Associated with the sedative effect of first-generation H 1 -AGPs is the myth that their use is preferable in the treatment of patients with concomitant insomnia, and if this effect is undesirable, it can be neutralized by using the drug at night. It should be remembered that first-generation antihypertensive drugs inhibit the REM sleep phase, which disrupts the physiological process of sleep and does not fully process information during sleep. When using them, breathing problems may occur, heart rate, which increases the risk of developing sleep apnea. In addition, in some cases, the use of high doses of these drugs contributes to the development of paradoxical arousal, which also negatively affects the quality of sleep. It is necessary to take into account the difference in the duration of the antiallergic effect (1.5-6 hours) and the sedative effect (24 hours), as well as the fact that long-term sedation is accompanied by impaired cognitive functions.
The presence of pronounced sedative properties debunks the myth about the advisability of using first-generation H 1 -AGP in elderly patients who use these drugs, guided by established stereotypes of habitual self-medication, as well as recommendations of doctors who are not sufficiently informed about pharmacological properties drugs and contraindications to their use. Due to the lack of selectivity of effects on alpha-adrenergic receptors, muscarinic, serotonin, bradykinin and other receptors, a contraindication to the prescription of these drugs is the presence of diseases that are quite common among elderly patients - glaucoma, benign prostatic hyperplasia, bronchial asthma, chronic obstructive pulmonary disease, etc. .
The myth that there is no place in clinical practice for first-generation antihypertensive drugs
Despite the fact that first-generation H 1 -AGPs (most of them were developed in the middle of the last century) can cause known side effects, they are still widely used in clinical practice today. Therefore, the myth that with the advent of a new generation of AGP there is no room left for the previous generation of AGP is invalid. The first generation N 1-AGP has one undeniable advantage - the presence of injection forms, which are indispensable in providing emergency care and premedication before certain types of diagnostic examination, surgical interventions, etc. In addition, some drugs have an antiemetic effect, reduce anxiety, and are effective against motion sickness. The additional anticholinergic effect of a number of drugs in this group is manifested in a significant reduction in itching and skin rashes with itchy dermatoses, acute allergic and toxic reactions to foods, medications, insect bites and stings. However, it is necessary to prescribe these drugs with strict consideration of indications, contraindications, severity clinical symptoms, age, therapeutic dosages, side effects. The presence of pronounced side effects and the imperfection of first-generation H 1 -AGP contributed to the development of new second-generation antihistamines. The main directions for improving drugs were increasing selectivity and specificity, eliminating sedation and tolerance to the drug (tachyphylaxis).
Modern H 1 -AGPs of the second generation have the ability to selectively act on H 1 receptors, do not block them, but, being antagonists, transfer them to an “inactive” state without disturbing their physiological properties, have a pronounced antiallergic effect, a rapid clinical effect, act long-term (24 hours), do not cause tachyphylaxis. These drugs practically do not penetrate the blood-brain barrier, therefore they do not cause sedation or impairment of cognitive functions.
Modern second-generation H 1 -AGPs have a significant antiallergic effect - they stabilize the mast cell membrane, suppress the eosinophil-induced release of interleukin-8, granulocyte macrophage colony-stimulating factor (GM-CSF) and soluble molecule intercellular adhesion 1 (Soluble Intercellular Adhesion Molecule-1, sICAM-1) of epithelial cells, which contributes to greater efficiency compared to first-generation H 1 -AGP in the basic therapy of allergic diseases, in the genesis of which late-phase mediators play a significant role allergic inflammation.
In addition, an important characteristic of second-generation H1-AGPs is their ability to provide an additional anti-inflammatory effect by inhibiting the chemotaxis of eosinophils and neutrophil granulocytes, reducing the expression of adhesion molecules (ICAM-1) on endothelial cells, inhibiting IgE-dependent platelet activation and the release of cytotoxic mediators. Many doctors do not pay due attention to this, however, the listed properties make it possible to use such drugs for inflammation not only of an allergic nature, but also of an infectious origin.
The myth about the same safety of all second-generation AGPs
There is a myth among doctors that all second-generation H1-AGPs are similar in their safety. However, in this group of drugs there are differences associated with the peculiarities of their metabolism. They may depend on the variability in the expression of the CYP3A4 enzyme of the liver cytochrome P 450 system. Such variability may be due to genetic factors, diseases of the hepatobiliary system, simultaneous administration a number of drugs (macrolide antibiotics, some antimycotic, antiviral drugs, antidepressants, etc.), products (grapefruit) or alcohol that have an inhibitory effect on the oxygenase activity of the CYP3A4 cytochrome P450 system.
Among the second generation N1-AGP there are:
Rice. 1. Features of metabolism of H 1 -AGP of the second generation
The advantages of active metabolites, the intake of which is not accompanied by additional load on the liver, are obvious: the speed and predictability of the development of the effect, the possibility joint reception with various drugs and food products that undergo metabolism with the participation of cytochrome P450.
The myth of more high efficiency each new AGP
The myth that new N1-AGP agents that have appeared in recent years are obviously more effective than the previous ones has also not been confirmed. The works of foreign authors indicate that second-generation H 1 -AGPs, for example cetirizine, have more pronounced antihistamine activity than second-generation drugs, which appeared much later (Fig. 2).
Rice. 2. Antihistamine comparative activity of cetirizine and desloratadine on the effect on the skin reaction caused by the administration of histamine within 24 hours 
It should be noted that among second-generation H 1 -AGPs, researchers assign a special place to cetirizine. Developed in 1987, it became the first original highly selective H1 receptor antagonist, obtained on the basis of a pharmacologically active metabolite of the previously known first-generation antihistamine - hydroxyzine. To this day, cetirizine remains a kind of standard of antihistamine and antiallergic action, used for comparison in the development of new antihistamines and antiallergic drugs. There is an opinion that cetirizine is one of the most effective antihistamine H1 drugs, it was more often used in clinical studies, the drug is preferable for patients who respond poorly to therapy with other antihistamines.
The high antihistamine activity of cetirizine is due to the degree of its affinity for H1 receptors, which is higher than that of loratadine. It should also be noted that the drug has a significant specificity, since even in high concentrations it does not have a blocking effect on serotonin (5-HT 2), dopamine (D 2), M-cholinergic receptors and alpha-1 adrenergic receptors.
Cetirizine meets all the requirements for modern second-generation AGPs and has a number of features. Among all known AGPs, the active metabolite cetirizine has the smallest volume of distribution (0.56 l/kg) and ensures full occupancy of H1 receptors and the highest antihistamine effect. The drug is characterized by a high ability to penetrate the skin. 24 hours after taking a single dose, the concentration of cetirizine in the skin is equal to or higher than the concentration in the blood. Moreover, after course treatment The therapeutic effect lasts up to 3 days. The pronounced antihistamine activity of cetirizine makes it stand out among modern antihistamines (Fig. 3).
Rice. 3. Efficacy of a single dose of second-generation H 1 -AGP in suppressing histamine-induced wheal reaction over 24 hours in healthy men 
Myth about high cost all modern AGPs
Any chronic illness does not immediately respond even to adequate therapy. It is known that insufficient control over the symptoms of any chronic inflammation leads not only to a deterioration in the patient’s well-being, but also to an increase in overall treatment costs due to an increased need for drug therapy. The selected drug must have the most effective therapeutic effect and be affordable. Doctors who remain committed to prescribing first-generation H 1 -AGPs explain their choice by referring to another myth that all second-generation AGPs are much more expensive than first-generation drugs. However, in addition to original drugs, there are generics on the pharmaceutical market, the cost of which is lower. For example, currently, in addition to the original (Zyrtec), 13 generics of cetirizine preparations are registered. The results of the pharmacoeconomic analysis are presented in table. 2 indicate the economic feasibility of using Cetrin, a modern second-generation AGP.
Table 2.
Results of comparative pharmacoeconomic characteristics of H1-AGP of the first and second generations
| A drug | Suprastin 25 mg No. 20 | Diazolin 100 mg No. 10 | Tavegil 1 mg No. 20 | Zyrtec 10 mg No. 7 | Cetrin 10 mg No. 20 |
| Average market value of 1 package | 120 rub. | 50 rub. | 180 rub. | 225 rub. | 160 rub. |
| Frequency of reception | 3 times/day | 2 times/day | 2 times/day | 1 r/day | 1 r/day |
| Cost of 1 day of therapy | 18 rub. | 10 rub. | 18 rub. | 32 rub. | 8 rub. |
| Cost of 10 days of therapy | 180 rub. | 100 rub. | 180 rub. | 320 rub. | 80 rub. |
The myth that all generics are equally effective
The question of the interchangeability of generics is relevant when choosing the optimal modern antihistamine drug. Due to the variety of generics presented on the market of pharmacological drugs, a myth has arisen that all generics act approximately the same, so you can choose any one, focusing primarily on price.
Meanwhile, generics differ from each other, and not only in their pharmacoeconomic characteristics. Stability of the therapeutic effect and therapeutic activity of the reproduced drug are determined by the features of technology, packaging, quality of active substances and excipients. The quality of active substances of drugs from different manufacturers may vary significantly. Any change in the composition of excipients may reduce bioavailability and cause side effects, including hyperergic reactions of different nature(toxic, etc.). The generic must be safe to use and equivalent original drug. Two drugs are considered bioequivalent if they are pharmaceutically equivalent, have the same bioavailability and, when administered at the same dose, are similar, providing adequate efficacy and safety. According to recommendations World Organization healthcare, the bioequivalence of a generic should be determined in relation to the officially registered original medicinal product. Studying bioequivalence is one of the stages of studying therapeutic equivalence. The FDA (Food and Drug Administration (USA)) annually issues and publishes the “Orange Book” with a list of drugs that are considered therapeutically equivalent to the original ones. Thus, any doctor can make the optimal choice of a safe antihistamine, taking into account all possible characteristics of these drugs.
One of the highly effective generics of cetirizine is Cetrin. The drug acts quickly, lasts, and has a good safety profile. Cetrin is practically not metabolized in the body, the maximum concentration in the serum is reached an hour after administration, and with prolonged use it does not accumulate in the body. Cetrin is available in 10 mg tablets and is indicated for adults and children over 6 years of age. Cetrin is completely bioequivalent to the original drug (Fig. 4).
Rice. 4. Average dynamics of cetirizine concentration after taking the compared drugs 
Cetrin is successfully used as part of the basic therapy of patients with allergic rhinitis who have sensitization to pollen and household allergens, allergic rhinitis associated with atopic bronchial asthma, allergic conjunctivitis, urticaria, including chronic idiopathic, pruritic allergic dermatoses, angioedema, as well as as symptomatic therapy for acute viral infections in patients with atopy. When comparing the effectiveness of generic cetirizine in patients with chronic urticaria when using Cetrin, best results(Fig. 5) .
Rice. 5. Comparative assessment of the clinical effectiveness of cetirizine drugs in patients with chronic urticaria 
Domestic and Foreign experience use of Cetrin indicates its high therapeutic effectiveness V clinical situations when the use of second-generation H1-antihistamines is indicated.
Thus, when choosing the optimal H 1 -antihistamine drug from all drugs presented on the pharmaceutical market, one should be based not on myths, but on selection criteria, including maintaining a reasonable balance between effectiveness, safety and accessibility, the presence of a convincing evidence base, and high quality production .
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There are three (according to some authors - four) generations of antihistamines. The first includes drugs that, in addition to antiallergic, also have a sedative/hypnotic effect. The second includes drugs with a minimally pronounced sedation effect and a powerful antiallergic effect, but in some cases causing serious, life-threatening arrhythmias. Antihistamine drugs of the new - third - generation are metabolic products (metabolites) of second-generation drugs, and their effectiveness is 2-4 times higher than that of their predecessors. They have a number of unique positive properties and do not cause side effects such as drowsiness and negative impact on the heart. It is the third generation drugs that will be discussed in this article.
New (third) generation antihistamines: mechanism of action and effects
Medicines in this group act exclusively on H1-histamine receptors, that is, they have selectivity of action. Their antiallergic effect is also ensured due to the following mechanisms of action. So, these drugs:
- inhibit the synthesis of mediators of systemic allergic inflammation, including chemokines and cytokines;
- reduce the number and disrupt the functions of adhesion molecules;
- inhibit chemotaxis (the process of release of leukocytes from the vascular bed into damaged tissue);
- inhibit the activation of allergy cells and eosinophils;
- inhibit the formation of superoxide radical;
- reduce increased reactivity (hyperreactivity) of the bronchi.
All of the above mechanisms of action provide powerful antiallergic and, to a certain extent, anti-inflammatory effects: eliminate itching, reduce the permeability of the capillary wall, swelling and hyperemia of tissues. Do not cause drowsiness, do not have a toxic effect on the heart. They do not bind to cholinergic receptors, therefore, do not cause side effects such as blurred vision and. They have a high safety profile. It is thanks to these properties that new generation antihistamines can be recommended for long-term treatment of a number of.
Side effects
As a rule, these drugs are well tolerated by patients. However, occasionally, while taking them, the following undesirable effects may develop:
- fatigue;
- dry mouth (extremely rare);
- hallucinations;
- drowsiness, insomnia, agitation;
- , heartbeat;
- nausea, vomiting, epigastric discomfort, in isolated cases -;
- muscle pain;
- allergic reactions: skin rashes, accompanied or not, shortness of breath, Quincke's edema, anaphylactic reactions.
Indications and contraindications for the use of third generation antihistamines
Food can cause food allergies and cause illness. Indications for the use of drugs in this group are:
- allergic rhinitis (both year-round and seasonal);
- (also seasonal and year-round);
- chronic;
- allergic;
New generation antihistamines are contraindicated only in case of individual hypersensitivity the patient's body to them.
Representatives of new generation antihistamines
This group of medicines includes:
- Fexofenadine;
- Cetirizine;
- Levocetirizine;
- Desloratadine.
Let's look at each of them in more detail.
Fexofenadine (Altiva, Telfast, Tigofast, Fexofast, Fexofen-Sanovel)
Release form: film-coated tablets of 120 and 180 mg.
Pharmacologically active metabolite of the second generation drug, terfenadine.
After oral administration, it is quickly absorbed in the digestive tract, reaching a maximum concentration in the blood after 1-3 hours. It almost does not bind to blood proteins and does not penetrate the blood-brain barrier. The half-life is 11-15 hours. It is excreted mainly in bile.
The antiallergic effect of the drug develops within 60 minutes after a single dose; within 6 hours the effect increases and persists throughout the day.
Adults and children over 12 years of age are recommended to take 120-180 mg (1 tablet) once a day, before meals. The tablet should be swallowed without chewing with 200 ml of water. The course of treatment is determined individually depending on the characteristics of the disease. Even after regular use of fexofenadine for 28 days, there were no signs of intolerance.
For patients suffering from severe or severe symptoms, the drug should be used with caution.
It should not be used during pregnancy, since clinical studies have not been conducted on this category of patients.
The drug passes into breast milk, so nursing mothers should not take it either.
Cetirizine (Allertek, Rolinoz, Cetrin, Amertil, Zodak, Cetrinal)
While taking antihistamines, you should avoid alcohol. Release form: film-coated tablets, solution and drops for oral use, syrup.
Metabolite of hydroxyzine. The strongest antagonist of H1-histamine receptors.
The use of this drug in average therapeutic doses significantly improves the quality of life of patients suffering from seasonal and chronic allergic rhinitis.
After oral administration, the effect appears after 2 hours and lasts for a day or more.
In patients with impaired renal function, the dose of cetirizine should be adjusted depending on the creatinine clearance: for renal mild insufficiency degree of severity, 10 mg of an antihistamine is prescribed once a day, which is the full dose; moderate degree – 5 mg 1 time per day (half dose); if the creatinine clearance rate corresponds to a severe degree of renal failure, it is recommended to take 5 mg of cetirizine every other day, and for patients on hemodialysis with end-stage renal failure, taking the drug is completely contraindicated.
Contraindications to the use of cetirizine are also individual hypersensitivity to it and congenital pathology carbohydrate metabolism (glucose-galactose malabsorption syndrome and others).
Cetirizine taken in usual doses, may cause such temporary adverse reactions such as fatigue, drowsiness, central nervous system agitation, dizziness and headache. In some cases, while taking it, dry mouth, impaired accommodation of the eye, difficulty urinating and increased activity of liver enzymes are noted. As a rule, after discontinuation of the drug, these symptoms disappear on their own.
During the treatment period, you should stop taking it.
Persons suffering from convulsive syndrome and epilepsy should take the drug with extreme caution due to increased risk occurrence .
During pregnancy, use if absolutely necessary. Do not take during lactation, as it is excreted in breast milk.
Levocetirizine (L-cet, Alerzin, Aleron, Zilola, Cetrilev, Aleron neo, Glencet, Xyzal)
Release form: film-coated tablets, drops for oral administration, syrup (dosage form for children).
Cetirizine derivative. The affinity for H1-histamine receptors of this drug is several times higher than that of its predecessor.
When taken orally, it is quickly and completely absorbed, and the degree of absorption does not depend on food intake, but its speed decreases in the presence of food in the stomach. In some patients, the effect of the drug begins within 12-15 minutes after administration, but in the majority it develops later, after 30-60 minutes. The maximum concentration in the blood is determined after 50 minutes and persists for 48 hours. The half-life is from 6 to 10 hours. Excreted by the kidneys.
In persons suffering from severe renal failure, the half-life of the drug is prolonged.
Excreted in breast milk.
Adults and children over 6 years of age are recommended to use the tablet form of the drug. 1 tablet (5 mg) is taken orally, without chewing, with a drink sufficient quantity water. Frequency of administration – 1 time per day. If levocetirizine is prescribed in the form of drops, the dose for adult patients and children 6 years of age and older is 20 drops once a day. Children under 6 years of age are prescribed in the form of syrup or drops, the dose of which depends on the age of the child.
Persons with severe renal impairment should have their creatinine clearance calculated before prescribing the drug. If this value indicates first-degree renal dysfunction, then the recommended dose of an antihistamine is 5 mg per day, that is, the full dose. In case of moderate renal dysfunction, it is 5 mg once every 48 hours, that is, every other day. In case of severe renal impairment, the drug should be taken 5 mg 1 time every 3 days.
The duration of treatment varies widely and is selected individually depending on the disease and the severity of its course. Thus, for hay fever, the course of treatment is usually 3-6 months, for chronic allergic diseases– up to 1 year, in case of potential contact with an allergen – 1 week.
Contraindications to the use of levocetirizine, in addition to individual intolerance and severe chronic renal failure, are congenital (galactose intolerance, lactase deficiency and others), as well as pregnancy and lactation.
Side effects are similar to those of other drugs in this group.
While taking levocetirizine, drinking alcoholic beverages is strictly contraindicated.
Desloratadine (Alersis, Lordes, Trexil neo, Erius, Eden, Alergomax, Allergostop, DS-Lor, Fribris, Eridez)
Release form: film-coated tablets, 5 mg each and an oral solution containing 0.5 mg of active substance per ml (dosage form for children). Some drugs, in particular Allergomax, are also available in the form of a nasal spray.
