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Emergency conditions in allergology Lecturer - professor, doctor of medical sciences. Nedelskaya S.N. ZDMUSlide 2
Urticaria (urticaria) is a disease characterized by the appearance on the skin of itchy spots, papules or blisters, quite clearly contoured, ranging in size from a few millimeters to ten or more centimeters. The rash appears quickly, the elements can merge and spread over the entire surface of the body. The elements persist for several hours, then gradually disappear and reappear elsewhere. If urticarial lesions persist for more than 24 hours, a diagnosis of urticarial vasculitis or delayed pressure urticaria should be considered.
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Angioedema is an acutely developing and relatively quickly passing swelling of the skin, subcutaneous tissue and/or mucous membranes ICD-10: T78.3 Angioedema D84.1 Complement system defect
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Etiological factors development of urticaria (K) and allergic edema (AO) are: Food or injection allergens (medicines, food products) latex
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substances that act directly on mast cells - opiates, X-ray contrast agents curare, tobaccocurine chloride, substances that disrupt the metabolism of arachidonic acid, aspirin, NSAIDs, some cyclooxygenase-2 inhibitors, physical stimuli, heat and cold, vibration, contact with water, pressure sunlight, ultraviolet physical exercise(cholinergic)
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idiopathic urticaria Other: nutritional supplements There is a separate hereditary variant of Urticaria.
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Treatment Goal: relief of symptoms of acute urticaria and selection of adequate therapy. Indications for hospitalization: severe forms OK, AO of the larynx with risk of asphyxia, all cases anaphylactic reaction Non-drug treatment: hypoallergenic diet, keeping a food diary, patient education
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Drug treatment Antihistamines H1-histamine blockers of the 1st, 2nd and 3rd generations Glucocorticoids: prednisolone 2-3-5 mg/kg body weight Sorbents
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Lyell's syndrome (toxic-allergic bullous epidermal necrolysis) The most severe form of LA Most often its development is caused by antibiotics, barbiturates, analgesics and NSAIDs Often its development is preceded by an acute infectious process, for which the drug that caused L syndrome was prescribed
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Clinic The disease develops within a few hours or days after taking the drug Prodromal period in the form of fever, weakness, headache and myalgia, skin hyperesthesia, itching of the conjunctiva Hyperthermia up to 39-40 C, a spotted and/or petechial rash appears, there may be urticaria or blisters Often the first rashes appear on the mucous membranes of the mouth, nose, genitals, and sometimes the eyes. Over the course of several days, erythroderma develops, against the background of which detachment of the epidermis begins with the formation of erosions
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Positive symptom Nikolsky Pain is sharply expressed in areas of rashes and erosions The condition progressively worsens, symptoms of dehydration occur The course of the disease resembles burn disease(symptom of burned skin) Damage to mucous membranes is typical in 90% (e) Prognosis depends on the prevalence of necrosis Mortality reaches 30%
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,
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Treatment B intensive care unit The first priority is support water-electrolyte and protein balance, treatment of affected erosive surfaces Antibiotics and glucocorticosteroids 5-15 mg/kg Locally - corticosteroid aerosols, antibacterial lotions on wet areas, solcoseryl ointment or cream, panthenol
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Stevens-Johnson syndrome The most severe form of bullous polymorphic exudative erythema, in which, along with skin lesions, there is damage to the mucous membranes of at least 2 organs Cause - penicillins, NSAIDs, anticonvulsants
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Anaphylactic shock Asphyxial Hemodynamic Abdominal Cerebral Mixed By type of course Acute benign Acute malignant Protracted Recurrent Abortive
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Urgent Care stop administration medicinal product that caused an allergic reaction Place the patient, turn his head to the side, push out lower jaw, fix the tongue. Provide access fresh air or inhale humidified oxygen. It is necessary to stop further entry of the allergen into the body:
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When introducing an allergen parenterally: prick the injection site (bite) crosswise with a 0.1% solution of adrenaline 0.1 ml/year of life in 5 ml saline. solution and apply ice to it, apply a tourniquet (if localization allows) proximal to the site of allergen introduction for 30 minutes, without squeezing the artery, if an allergic reaction occurred to the administration of penicillin, inject 1 million units. penicillinase in 2 ml. physical IM solution
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When introducing the allergen dropwise into the nose or eyes, rinse the latter with copious amounts of running water; If the allergen is administered orally, rinse the patient’s stomach if the condition allows. Immediately administer intramuscularly: 0.1% solution of adrenaline at a dose of 0.05-0.1 ml/year of life (no more than 1 ml) and 3% Prednisolone solution at a dose of 5 mg/kg into the fundus muscles oral cavity Antihistamines: 1% solution of diphenhydramine 0.05 ml/kg 9no more than 0.5 ml – for children under 1 year and 1 ml – for children older than one year) or 2% solution of suprastin 0.1-0.15 ml/year of life) The use of pipolfen is contraindicated due to its significant hypotensive effect! Mandatory monitoring of pulse, respiration and blood pressure!
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After completing the priority measures, provide access to the vein and inject a 0.1% adrenaline solution in a stream at a dose of 0.05-0.1 ml/year of life in 10 ml saline. sodium chloride solution Introduce intravenous glucocorticoids: 3% prednisolone solution 2-4 mg/kg (in 1 ml - 30 mg) or Hydrocortisone 4-8 mg/kg (in 1 ml suspension - 25 mg) or 0 ,4% dexamethasone solution 0.3-0.6 mg/kg (4 mg in 1 ml) Begin IV infusion therapy with 0.9% sodium chloride solution or Ringer's solution at the rate of 20 ml/kg for 20-30 minutes. In the future, if there is no stabilization of hemodynamic parameters - colloidal solution(reopolyglucin) at a dose of 20 ml/kg. The volume and speed of infusion is determined by the value of blood pressure, central venous pressure and the patient’s condition.
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If blood pressure becomes low, alpha-adrenergic agonists are administered intravenously every 10-15 minutes until the condition improves 0.1% adrenaline solution 0.05-0.01 ml/year of life (total dose up to 5 mg) or 0.2 % norepinephrine solution – 0.1 ml/year of life (no more than 1 ml) or 1% mesatone solution 0.1 ml/year of life (no more than 1 ml) If there is no effect - titrated intravenous administration of dopamine at a dose of 8-10 mcg/kg/min under the control of blood pressure and heart rate For bronchospasm and other respiratory disorders: Carrying out oxygen therapy Enter 2 .4% solution of aminophylline 0.5-1 ml/year of life (no more than 10 ml) intravenous bolus in 20 ml saline. solution Remove accumulated secretions from the trachea and oral cavity If stridor breathing appears and there is no effect from complex therapy– immediate intubation, and in some cases, vital signs– conicotomy. Questions that a doctor should ask before prescribing any medicine Does the patient himself or his relatives suffer from any allergic disease? Has the patient previously received this drug, and has he had any allergic reactions to its use? What drugs were the patient treated for a long time and in large doses? Did the patient receive injections of serums and vaccines? Does the patient have mycosis of the skin and nails (athlete's foot, trichophytosis). Does the patient have professional contact with medications? Does it cause exacerbation of the underlying disease or the appearance allergic symptoms contact with animals? Prevention of drug allergies Before prescribing any drug, the doctor must answer the following questions: Is it true? this medicine necessary for the patient What will happen if it is not prescribed What do I want to achieve by prescribing this drug What are its side effects?
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Primary prevention prevention of the development of LA: Avoid polypharmacy, doses of drugs should correspond to the age and weight of the patient, strict adherence to the instructions for the method of drug administration. Secondary prevention prevention of LA in people suffering from allergic diseases. Patient education - the doctor gives the patient a leaflet “Passport of a patient with an allergic disease”
Allergic reactions is a consequence of increased sensitivity (sensitization) to various substances that have antigenic properties. Basically, the nature of the allergen remains uncertain, so treatment of patients with allergic reactions is carried out using the method of nonspecific hyposensitization - that is, using drugs that affect allergy processes regardless of the nature of the antigen.
There are 3 stages of development of allergic reactions:
1) immunological - formation of antibodies
2) release of allergy mediators
3) the reaction of organs and systems to these mediators.
Various medications pharmacological groups influence all stages of development of allergic reactions.
Classification of antiallergic drugs
|
Antihistamines (receptor blockers) |
Anti honey Iatorni drugs and membrane stabilizers |
Drugs that eliminate allergic reactions |
|
And generations Diphenhydramine (diphenhydramine, calmaben) Suprastin (supragistim, chloropyramine, Suprostilin) tavegil (clemastine) Diazol dr (mebgidrolin) Pipolfen (diprazine, promethazine) Hifenadia (fencarol) II generation Loratadine (Claritin, Lomiran, Erolin, Agistam, Lorana, Lorizan, Lorfast) Terfenadine (Trexil) Astemizole (Gismanal) Azelastine (alergodil) Fenistil Bbastin (kestin, Elert) Primalan Cetirizine (Zyrtec, Allertec, Analergin, Zodak, Cetrin) III generation Fexofenadine (Telfast, Altiva, Letizen, Fexofast) Erius (desloratadine) |
Cromolyn sodium (intal) Ketotifen (zaditen) |
Adrenergic agonists Bronchodilators Calcium preparations |
First generation antihistamines are central nervous system depressants and exhibit sedative and hypnotic effects.
Second generation antihistamines have little effect on the central nervous system and therefore have a slight sedative effect and a much longer pharmacological effect.
Antihistamines III generation are active metabolites of II generation drugs, providing them with the greatest selective effect on histamine receptors (they are the most active).
Antimediator drugs and membrane stabilizers prevent the release of allergy mediators.
Drugs that eliminate the manifestations of allergic reactions - adrenomimetics (adrenaline hydrochloride, ephedrine hydrochloride), bronchodilators (see Chapter 5), calcium preparations (see Chapter 13), reduce vascular permeability, constrict blood vessels and increase blood pressure, exhibit a bronchodilator effect.
Antihistamines- agents that block histamine receptors and prevent the action of histamine on them.
Diphenhydramine(dipheninhydramine) - an antihistamine, has a pronounced antiallergic, sedative, hypnotic, anti-emetic, mycetoanesthetic effect; enhances the effect of CNS depressants. Duration of action - 4-6 hours.
Indications for use: anaphylactic shock, urticaria, allergic dermatitis, rhinitis, hay fever (hay fever), to enhance the effect of sleeping pills, analgesics and anesthesia, etc.
Side effects: dry mouth, loss of coordination, dizziness, headache, drowsiness, decreased performance.
Suprastin(chloropyramine) is a highly active antihistamine, has a less pronounced antiallergic effect than diphenhydramine, and depresses the central nervous system to a lesser extent. Prevents the manifestations of allergic reactions and alleviates them, has antiallergic, sedative and hypnotic effects.
Duration of action - 8-12 hours.
Indications for use: anaphylactic shock, angioedema, urticaria, itching, skin diseases(neurodermatitis, contact dermatitis etc.), allergic dermatitis, rhinitis, containing complex treatment patients with bronchial asthma, etc.
Side effects: drowsiness, dizziness, loss of coordination, dry mouth, nausea.
Diazolin(mebhydrolin) is an antihistamine for oral administration. It has a weak antiallergic, antispasmodic effect and does not have a calming effect.
Indications for use: with allergies to medications, products (urticaria, itching, allergic dermatitis).
Side effects: irritation of the gastric mucosa, nausea, vomiting, drowsiness, slow reaction.
Contraindications: peptic ulcer and duodenum, inflammatory diseases gastrointestinal tract.
Loratadine(claritin, clarotadin, lomiran, erolin) - a second generation antihistamine that selectively acts on peripheral histamine H2 receptors. The antiallergic effect begins after 1-3 hours, maximum after 8-12 hours, the duration of action is more than 24 hours.
It is excreted in the form of metabolites in urine and feces in equal proportions.
Indications for use: seasonal and year-round rhinitis, skin diseases of allergic origin, Quincke's edema, allergic reactions for insect bites.
Side effects: drowsiness, fatigue, dry mouth, nausea.
Fexofenadine(Telfast, Fexadine) is a third generation antihistamine, is a highly active metabolite of terfenadine and exhibits high selectivity to receptors. The drug does not depress the central nervous system. The onset of action is observed after 1 hour, the maximum effect is after 6 hours, the duration of action is 24 hours. It is not metabolized in the liver, it is excreted mainly in bile.
Indications for use: seasonal allergic rhinitis, chronic idiopathic urticaria.
Side effects: appear very rarely.
Glucocorticosteroids(see Chapter 12) - hormones of the adrenal cortex have a pronounced antiallergic effect, affecting all stages of the development of allergic reactions. The drugs are used for any allergic reactions of severe and moderate severity (anaphylactic shock, Quincke's edema, serum sickness), progressive serious illnesses allergic nature- bronchial asthma, collagenosis, polyarthritis, rheumatism. When using GCS, you should remember their pronounced side effects.
Cromolyn sodium(intal) is a mast cell stabilizer that prevents their destruction and the release of allergy mediators. Used inhalation using a special turbo inhaler. Systemic administration - prevention of attacks bronchial asthma. Ineffective during an attack.
Contraindications: age up to 5 years; I trimester of pregnancy.
Emergency care for anaphylactic shock Anaphylactic shock is a severe manifestation of allergies:
In the pre-shock period, it is necessary to administer antihistamines - suprastin, diprazine (pipolfen), diphenhydramine, tavegil;
If there is a decrease in blood pressure and bronchospasm, prescribe adrenaline hydrochloride (0.5 ml of a 0.1% solution subcutaneously every 5-10 minutes, if there is no effect - intravenously, diluted 10 times), ephedrine hydrochloride. Effective intravenous drip (40-50 per 1 min) administration of an anti-shock mixture - 5 ml of 0.1% solution of adrenaline hydrochloride and 0.06 g of prednisolone (2 ampoules), dissolved in 500 ml of isotonic sodium chloride
For bronchospasm, other bronchodilators should also be administered (see Chapter 6);
In case of respiratory depression, use oxygen therapy, administer respiratory stimulants (analeptics - see Chapter 5);
At acute edema lungs - administer diuretics - furosemide, mannitol;
Correction of hemodynamic disorders ( saline solutions, plasma expanders, etc.).
Pharmacosafety: - antihistamines are not compatible with promedol, streptomycin, kanamycin, neomycin, tricyclic antidepressants;
- Diphenhydramine and diprazine (pipolphen) cause irritation when administered subcutaneously, so they should be administered parenterally - intramuscularly or intravenously;
- Diphenhydramine is not compatible with ascorbic acid, sodium bromide, gentamicin;
- All antihistamines that depress the central nervous system (diphenhydramine, diprazine, suprastin, tavegil) should not be prescribed to patients whose work requires a precise mental reaction (drivers, operators, etc.);
- It is advisable to administer Diazolin orally after meals
- Cromolyn sodium cannot be administered by inhalation together with bromhexine and ambroxol.
facilities
The term “allergy” comes from Greek words allos – different and ergon – work, activity, and literally means “doing differently”. We owe the appearance of this term to the Viennese pediatrician Clement von Pirke. A substance that can cause an allergic reaction is called an allergen.
Allergic diseases are very common and, according to the World Health Organization, affect about 40% of the world's population.
Antihistamines
Histamine, stimulating histamine H1 receptors, is involved in the occurrence of almost all the main symptoms of allergies. Therefore, antihistamines are always used as antiallergic drugs.
By modern classification antihistamines
drugs (H1-histamine blockers) are divided into two groups: 1) H 1 -histamine blockers
I generation, having noticeable sedatives
properties; 2) H1-histamine blockers of the second generation , non-sedating or having a slight sedative effect.
Antihistamines
IN last years developed and implemented in clinical practice advanced H1-histamine blockers, which are pharmacologically active metabolites that lack side effects parent compound: metabolite of the H1-histamine blocker of the first generation hydroxyzine - cetirizine, which rarely has a weak sedative effect; metabolite H1 -
second generation histamine blocker terfenadine - fexofenadine, which does not have sedatives
properties; metabolite of the H1-histamine blocker of the second generation loratadine - desloratadine, rarely
having a mild sedative effect; levorotatory isomer of cetirizine - levocetirizine,
without sedative properties.
Antihistamines
The main side effects of H1 - first generation histamine blockers: blockade of other receptors (for example,m-cholinergic receptors,which manifests itself in the form of dryness of the mucous membrane of the mouth, nose, pharynx, bronchi; urination disorder and visual impairment rarely occur); local anesthetic effect; quinidine-like effect on the heart muscle; effect on the central nervous system (sedation, loss of coordination, dizziness, lethargy, decreased ability to concentrate); increased appetite; disorders of the gastrointestinal tract (nausea, vomiting, diarrhea, loss of appetite, discomfort in the epigastrium).
Antihistamines
Advantages of H1 - second generation histamine blockers:
very high specificity and high affinity for H1 receptors;
rapid onset of action; sufficient duration of the main effect (up to 24 hours); absence of blockade of other types of receptors; minor penetration or obstruction of the BBB at therapeutic doses; lack of connection between absorption and food intake; absence of tachyphylaxis.
Antihistamines
The main side effects of H1 - second generation histamine blockers. At therapeutic doses, these drugs have a good safety profile. However, when their metabolism is slowed down by liver enzymes (CYP3A4 of the cytochrome system R-450) occurs
accumulation of unmetabolized parent forms, which leads to violation heart rate (ventricular
fusiform tachycardia, ECG shows prolongation
Q-T interval). This side effect is typical for terfenadine, astemizole and loratadine. Due to cardiotoxic effects, terfenadine and astemizole have been withdrawn from sale in a number of countries.
The effect on the central nervous system of drugs in this group is extremely weak. Sedation is rare and occurs only in individuals with high individual sensitivity to drugs.
First generation antihistamines
Clemastine (suprastin tablet, 25 mg; solution d/in. amp., 20 mg/ml, 1 ml).
Dimetindene ( fenistil, fenistil 24 rr-drops for oral administration
(vial) 0.1%, 20 ml; caps. retard, 4 mg; gel d/nar. approx. (tubes) 0.1%, 30 g).
Mebhydrolin (diazolin)
dragees, 0.05 and 0.1 g).
Mequitazine (primalan tablet, 5 and 10 mg).
Quifenadine (fenkarol tablet.
tab., 10, 25 and 50 mg).
Antihistamines for topical use
Advantages: absence of side effects that may occur with systemic use of drugs; easy achievement of high local concentrations of drugs on the mucous membranes and rapid onset of action.
Cetirizine (Zyrtec)
table, cover vol., 10 mg; solution drops for oral administration (vial), 10 mg/ml, 10 and 20 ml).
Desloratadine
(erius tablet, coating volume, 5 mg; syrup 0.5 mg/ml).
INTRODUCTION
Antihistamines are commonly called drugs that block H1 and H2 histamine receptors.
Histamine, this most important mediator of various physiological and pathological processes in the body, was chemically synthesized in 1907. Subsequently, it was isolated from animal and human tissues (Windaus A., Vogt W.). Even later, its functions were determined: gastric secretion, neurotransmitter function in the central nervous system, allergic reactions, inflammation, etc. Almost 20 years later, in 1938, the first substances with antihistamine activity were created (Bovet D, Staub A.). And already in the 60s, the heterogeneity of histamine receptors in the body was proven and three of their subtypes were identified: H1, H2 and NZ, differing in structure, localization and physiological effects that occur during their activation and blockade. From this time on, an active period of synthesis and clinical testing of various antihistamines began.
Numerous studies have shown that histamine, acting on receptors in the respiratory system, eyes and skin, causes characteristic allergy symptoms, and antihistamines that selectively block H1-type receptors are able to prevent and relieve them. Drugs that block H1-histamine receptors are used to treat allergic diseases. Agents that block H2-histamine receptors reduce secretion and are used as antiulcer drugs.
Most of the antihistamines used have a number of specific pharmacological properties that characterize them as a separate group. These include the following effects: antipruritic, decongestant, antispastic, anticholinergic, antiserotonin, sedative and local anesthetic, as well as prevention of histamine-induced bronchospasm. Some of them are caused not by histamine blockade, but by structural features.
1. HISTAMINE
Histamine (Histaminum) (4-(2-Aminoethyl)-imidazole, or -imidazolyl-ethylamine) is a biogenic compound formed in the body by decarboxylation of the amino acid histidine. Histamine is found in mast cells, basophils, and leukocytes.
Histamine is one of the endogenous mediators involved in the regulation of vital functions of the body and plays important role in the pathogenesis of a number of painful conditions.
IN normal conditions histamine is found in the body primarily in a bound, inactive state. For various pathological processes (anaphylactic shock, burns, frostbite, hay fever, urticaria and others allergic diseases), as well as upon entry into the body of certain chemical substances the amount of free histamine increases. In this case, histamine causes spasm of smooth muscles (including bronchial muscles), dilation of blood vessels and a decrease in blood pressure, increased capillary permeability and, as a result, tissue swelling. Histamine causes increased secretion of gastric juice.
With intradermal and subcutaneous administration of histamine, after a few seconds, redness, local swelling, and a feeling of pain and itching develop at the injection site. These symptoms are based on local dilation of capillaries, increased vascular permeability and irritation of sensitive nerve endings.
Histamine is a natural ligand of specific histamine (H) receptors localized in various organs and tissues. There are 3 subtypes of histamine receptors: H1, -, H2, -, H3, receptors.
H1 receptors are localized in the bronchi and intestines (when they are excited, the smooth muscles of these organs contract), in the blood vessels (vasodilation occurs). H2 receptors are located on the parietal cells of the stomach (when stimulated, the secretion of hydrochloric acid increases). The central nervous system contains H1, H2 and H3 receptors. Together with H1 receptors, H2 receptors play a role in the development of allergic and immune reactions. H2 receptors are also involved in the mediation of excitation in the central nervous system.
The first substances with antihistamine activity were created in 1936. In the 60s, a period of active synthesis and clinical testing of various antihistamines began. IN Lately They began to attach great importance to the stimulation of H3 receptors in the mechanism of the central action of histamine, and a search is underway for drugs that activate and inhibit the functions of this group of receptors.
Antihistamines that block H1-histamine receptors are used to treat allergic diseases. Antihistamines that block histamine H2 receptors are used as antiulcer drugs.
2. H1-HISTAMINE RECEPTOR BLOCKERS
Antihistamines that block H1 receptors are used for immediate allergic reactions: urticaria, itching, allergic conjunctivitis, angioedema (Quincke's edema), allergic rhinitis, etc. These drugs block H1 histamine receptors in organs and tissues and make them insensitive to free histamine. They have virtually no effect on the release of free histamine.
Rice. 1. Scheme of development of an immediate allergic reaction and the direction of action of antiallergic drugs.
When foreign substances - antigens - act on the body, the system is activated humoral immunity and antibodies (immunoglobulins E) are formed, which are fixed on mast cells. When this antigen re-enters the body, it interacts with IgE antibodies on the surface mast cells. This causes degranulation of mast cells and the release of mediators of allergy and inflammation from them: histamine, bradykinin, prostaglandins, slow-reacting substance of anaphylaxis, etc. As a result of the action of allergy mediators on tissues and organs, allergic reactions develop, which can manifest themselves in the form of bronchospasm, dilation of capillaries and redness of the skin, increased capillary permeability and the development of edema, decreased blood pressure, etc.
Most antihistamines that block H1 receptors, in their own way chemical structure refers to fat-soluble amines that have a similar structure. The core (R1) is represented by an aromatic or heterocyclic group and is linked via a nitrogen, oxygen or carbon molecule to an amino group. The core determines the severity of antihistamine activity and some of the properties of substances.
There are several classifications of antihistamines, although none of them is generally accepted. According to their chemical structure, antihistamines are divided into several groups (ethanolamines, ethylenediamines, alkylamines, derivatives of alphacarboline, quinuclidine, phenothiazine, piperazine and piperidine). The most popular classification is based on the time of creation: first and second generation drugs. First generation drugs are also commonly called sedatives (based on the dominant side effect) in contrast to non-sedating second generation drugs. Currently, it is customary to distinguish the third generation: it includes fundamentally new drugs - active metabolites, which, in addition to the highest antihistamine activity, exhibit the absence of a sedative effect and the cardiotoxic effect characteristic of second-generation drugs.
2.1. FIRST GENERATION ANTIHISTAMINES
All first-generation antihistamines (sedatives) are highly soluble in fats and, in addition to H1-histamines, also block cholinergic, muscarinic and serotonin receptors. As competitive blockers, they reversibly bind to H1 receptors, which necessitates the use of fairly high doses. The following pharmacological properties are most characteristic of them:
The sedative effect is determined by the fact that most first-generation antihistamines, easily soluble in lipids, penetrate well through the blood-brain barrier and bind to H1 receptors in the brain. The degree of manifestation of the first generation sedative effect varies between drugs and in different patients from moderate to severe and increases when combined with alcohol and psychotropic drugs. Some of them are used as sleeping pills. Psychomotor agitation rarely occurs (more often in moderate therapeutic doses in children and in high toxic doses in adults). Because of the sedative effect, most medications should not be used while performing tasks that require alertness. All first-generation drugs potentiate the effect of sedatives and hypnotics, narcotic and non-narcotic analgesics, monoamine oxidase inhibitors and alcohol.
Atropine-like reactions (due to the anticholinergic properties of the drugs) are manifested by dry mouth and nasopharynx, urinary retention, constipation, tachycardia and visual disturbances. These properties may be useful for rhinitis, but may increase obstruction respiratory tract with bronchial asthma (due to an increase in sputum viscosity), cause exacerbation of glaucoma and prostate adenoma, etc.
They have antiemetic and anti-sickness effects, reduce the symptoms of parkinsonism - thanks to the central anticholinergic effect of the drugs.
May cause a transient decrease in blood pressure in sensitive individuals.
A local anesthetic (cocaine-like) effect is characteristic of most antihistamines.
Tachyphylaxis (decreased antihistamine activity): with long-term use, medications must be changed every 2-3 weeks.
The therapeutic effect occurs relatively quickly, but is short-lived (effective within 4-5 hours).
Some first-generation antihistamines are included in combination medications used for colds, motion sickness, as sedatives, sleeping pills and other components.
The most commonly used is diphenhydramine , chloropyramine, clemastine, cyproheptadine, promethazine, fencarol and hydroxyzine.
1) Diphenhydramine, best known in our country under the name diphenhydramine.
DIMEDROL (Dimcdrolum).
2-Dimethylaminoethyl ether benzhydrol hydrochloride, or N,N1-dimethyl-2-(diphenylmethoxy)ethylamine hydrochloride:
SYNONYMS: Allergies, Alledryl, Allergan, Allergin, Allergival, Amidryl, Bcnadryl, Benzhydraminum, Diabenyl, Dimedryl, Dimidril, Diphenhydramine, Diphenhydramine Hydrochloride, Restamin, etc.
White fine-crystalline powder with a bitter taste; causes numbness of the tongue. Hygroscopic. Easily soluble in water, very easily in alcohol.
Diphenhydramine is one of the first antihistamines (first generation drug) that has found widespread use in medical practice since the 1950s. Despite the emergence of a number of new antihistamines, diphenhydramine has not lost its importance to this day.
It is a blocker of histamine H1 receptors and has pronounced antihistamine activity. It has a local anesthetic effect and relaxes smooth muscles. Shows moderate antiemetic effect.
Diphenhydramine is well absorbed when taken orally. Penetrates the blood-brain barrier. An important feature of diphenhydramine is its sedative effect: in appropriate doses it has a hypnotic effect.
Diphenhydramine is used mainly in the treatment of urticaria, hay fever, serum sickness, hemorrhagic vasculitis (capillary toxicosis), vasomotor rhinitis, angioedema, pruritic dermatoses, acute iridocyclitis, allergic conjunctivitis and other allergic diseases; allergic complications from taking various medications (including antibiotics), blood transfusions and blood-substituting fluids, and the use of enzyme and other drugs.
Antihistamines
Antihistamines
1. AGS I generation
2. AGS II generation
3. H1-blockers with membrane-stabilizing properties
4. Other drugs (histamine + normal human immunoglobulin)
Histamine, by stimulating H1 receptors, is involved in almost all allergy symptoms. Therefore, AGS is always used as antiallergic drugs.
H1 blockers are divided into 2 main groups:
First generation H1 blockers with noticeable sedative effect
Second generation H1 blockers, non-sedating or slightly sedating
blockade of other receptors (m-cholinergic receptors in the form of dryness of the mucous membranes of the mouth, nose, pharynx, bronchi, rarely urination disorder and blurred vision)
Local anesthetic effect
Quinidine-like effect on the heart muscle
Effect on the central nervous system (sedation, loss of coordination, dizziness, lethargy, decreased attention)
Increased appetite
Disorder of the gastrointestinal tract
very high specificity and high affinity for H1-R
Fast onset of action
Sufficient duration of the main effect (up to 24 hours)
No blockade of other types of receptors
Obstruction through the BBB in therapeutic doses
Absorption is not related to food intake
Absence of tachyphylaxis
At therapeutic doses they have a good safety profile
slowing down metabolism by liver enzymes
accumulation of original forms
heart rhythm disorder (ventricular
tachycardia)
terfenadine and astemizole (withdrawn from sale in the Russian Federation), loratadine.
Effect on the central nervous system (extremely weak effect)
There is no information on the teratogenicity of AGS
does not have a teratogenic effect: clemastine, dimethindene, diphenhydramine, hydroxyzine, mebhydrolin, pheniramine
With long-term treatment of AGS up to delivery, NR showed withdrawal symptoms (tremor, diarrhea)
It is recommended to avoid the use of loratadine, hydroxyzine, disloratadine, mizolastine, cetirizine, and first generation AGS during pregnancy
Significant amounts of some drugs are present in breast milk. Although there is no information on the harmful effects of cetirizine, cyproheptadine, desloratadine, hydroxyzine and loratadine (it is recommended to avoid use)
Ketotifen - exclude!
Clemastine Causes Adverse Effects in Infants
Synonyms:
Synonyms: Pipolfen, Allergan, Antiallersin, Atosil,
Fargan, Phenergan, Promazinamide, Promethazine, Prothazin, etc.
phenothiazine.
The clinical effect appears 20 minutes after oral administration (on average 15-60 minutes), 2 minutes after intramuscular administration or 3-5 minutes after intravenous administration and usually lasts for 4-6 hours (sometimes lasting up to 12 hours).
Prescribed orally, intramuscularly and intravenously.
The maximum daily dose for adults is 150 mg.
IM 25 mg 1 time/day, if necessary 12.5-25 mg every 4-6 hours.
pronounced antihistamine activity
has a significant effect on the central nervous system
sedative
hypnotic
antiemetic
antipsychotic
hypothermic effect
Prevents and soothes hiccups
allergic diseases (including urticaria, serum sickness, hay fever, allergic rhinitis, allergic conjunctivitis, angioedema, itching);
auxiliary therapy of anaphylactic reactions (after relief of acute manifestations by other means, for example, epinephrine/adrenaline);
as a sedative in the pre- and postoperative period;
to prevent or relieve nausea and vomiting associated with anesthesia and/or appearing in the postoperative period;
postoperative pain (in combination with analgesics);
kinetosis (to prevent and eliminate dizziness and nausea while traveling by transport);
as a component of lytic mixtures used to potentiate anesthesia in surgical practice (for parenteral use)
Histamine H1 receptor blocker, derivative ethylenediamine.
Prevents the development and facilitates the course of allergic reactions.
It has a moderate sedative and pronounced antipruritic effect.
Possesses:
- antiemetic effect,
-peripheral anticholinergic activity,
-moderate antispasmodic properties.
The therapeutic effect develops within 15-30 minutes after oral administration, reaches a maximum within the first hour after administration and lasts at least 3-6 hours.
hives;
angioedema (Quincke's edema);
serum sickness;
seasonal and year-round allergic rhinitis;
conjunctivitis;
contact dermatitis;
skin itching;
acute and chronic eczema;
atopic dermatitis;
food and drug allergies;
allergic reactions to insect bites.
Prescribed orally, intramuscularly and intravenously.
Prescribed orally, intramuscularly and intravenously.
Orally, adults are prescribed 25 mg (1 tablet) 3-4 (75-100 mg/day).
The dose can be gradually increased if the patient has no side effects, but the maximum dose should not exceed 2 mg/kg body weight.
The tablets should be taken orally during meals, without chewing and with plenty of water.
Parenterally, the drug should be administered intramuscularly.
IV administration is used only in acute severe cases under the supervision of a physician.
For adults, the drug is administered intramuscularly at 20-40 mg (1-2 amp.)
Pills
Pills
1 tab. clemastine hydrofumarate 1.34 mg, which corresponds to the content of clemastine 1 mg
1 ml 1 amp. clemastine hydrofumarate 1.34 mg 2.68 mg, which corresponds to the content of clemastine 1 mg 2 mg
Histamine H1 receptor blocker, derivative ethanolamine.
Histamine H1 receptor blocker, derivative ethanolamine.
Renders:
- antiallergic
-antipruritic effect
-reduces vascular permeability
-provides sedative
-m-anticholinergic effect
-does not have hypnotic activity
Prevents the development of vasodilation and contraction of smooth muscles induced by histamine. Reduces capillary permeability, inhibits exudation and the formation of edema, and reduces itching.
The antihistamine activity of the drug when taken orally reaches a maximum after 5-7 hours, persists for 10-12 hours, and in some cases up to 24 hours.
Drug interactions
Tavegil® potentiates the effect of drugs that depress the central nervous system (hypnotics, sedatives, tranquilizers), m-anticholinergics, and ethanol.
To use the tablets:
To use the tablets:
hay fever and other allergic rhinopathies;
urticaria of various origins;
itching, pruritic dermatoses;
acute and chronic eczema, contact dermatitis;
drug allergies;
insect bites and stings.
To use the solution for injection:
- anaphylactic or anaphylactoid shock and angioedema (as an additional remedy);
- prevention or treatment of allergic and pseudoallergic reactions (including with the administration of contrast agents, blood transfusions, diagnostic use of histamine).
Orally, adults and children over 12 years of age are prescribed 1 tablet (1 mg) in the morning and evening. In cases that are difficult to treat, the daily dose can be up to 6 tablets (6 mg).
The tablets should be taken before meals with water.
Adults are prescribed 2 mg (2 ml, i.e. the contents of one ampoule) intramuscularly or intravenously.
With the aim of prevention immediately before possible occurrence anaphylactic reaction or reaction in response to the use of histamine the drug is administered intravenously in a bolus at a dose of 2 mg (2 ml). The solution for injection in an ampoule can be further diluted with isotonic sodium chloride solution or 5% glucose solution in a ratio of 1:5. IV injections Tavegila should be carried out slowly, over 2-3 minutes.
Glaucoma
BPH
Hypersensitivity to Tavegil (Clemastine)
Hyperthyroidism and other thyroid diseases (thyroiditis, thyroid tumor, etc.)
Arterial hypertension
Stomach ulcer
When Tavegil (Clemastine) is used together with sedatives and hypnotics, an overdose can easily occur, leading to loss of coordination (risk of injury) and loss of consciousness.
Solution for intravenous and intramuscular administration 1 ml
Solution for intravenous and intramuscular administration 1 ml diphenhydramine 10 mg 1 ml - ampoules
Clinical and pharmacological group: 1st generation histamine H1 receptor blocker. Antiallergic drug
The effect on the central nervous system is due to the blockade of H3-histamine receptors in the brain and inhibition of central cholinergic structures.
-Relieves spasm of smooth muscles
-prevents and reduces allergic reactions,
- local anesthetics,
- antiemetic,
-sedative effect,
-moderately blocks cholinergic receptors of the autonomic ganglia,
-has a hypnotic effect.
The action develops within a few minutes, duration – up to 12 hours.
Antagonism with histamine manifests itself to a greater extent in relation to local vascular reactions during inflammation and allergies than to systemic ones, i.e. decrease in blood pressure. However, when administered parenterally to patients with a deficiency of circulating blood volume, a decrease in blood pressure and an increase in existing hypotension is possible due to the ganglion-blocking effect. In people with local brain damage and epilepsy, it activates (even in low doses) epileptic discharges on the electroencephalogram and can provoke an epileptic attack.
IV or IM.
IV or IM.
For adults and children over 14 years of age, IV or IM 1-5 ml (10-50 mg) of a 1% solution (10 mg/ml) 1-3 times a day; the maximum daily dose is 200 mg.
Drug interactions
Enhances the effect of ethanol and drugs that depress the central nervous system.
Monoamine oxidase inhibitors (MAOIs) enhance the anticholinergic activity of diphenhydramine.
Antagonistic interactions are observed when co-administered with psychostimulants.
Reduces the effectiveness of apomorphine as an emetic drug in the treatment of poisoning.
Enhances the anticholinergic effects of drugs with m-anticholinergic activity
Strengthens and prolongs the effect of opiates. It makes them more addictive. It also enhances the effect of depressants such as alcohol, phenobarbital and benzodiazepine drugs.
Trade names
Trade names Alerpriv®, Vero-Loratadine, Clalergin, Clargotyl®, Claridol, Clarisens®, Claritin®, Clarifarm, Clarifer®, Clarotadine®, Clarfast, Lomilan®, LauraHEXAL®, Loratadine, Loratadine-Verte, Loratadine-Hemofarm, Lotharen, Erolin®
FDA approved in 1993
In 2001, it was the most prescribed antiallergic drug in the world since 1994.
H1 receptor blocker (long-acting).
Inhibits the release of histamine and leukotriene from mast cells.
Possesses:
-antiallergic
-antipruritic
-Antiexudative
-reduces capillary permeability,
-prevents the development of tissue edema
-Relieves smooth muscle spasms
The antiallergic effect develops within 30 minutes, reaches a maximum after 8-12 hours and lasts 24 hours. The duration of action is significantly facilitated by the active metabolite desloratadine. Does not affect the central nervous system and is not addictive (because it does not penetrate the BBB)
Dosage regimen: Inside. The effervescent tablet is pre-dissolved in a glass of water (200 ml). The tablets should not be swallowed, chewed or sucked in the mouth.
Drug interactions
Erythromycin, cimetidine, ketoconazole increase the concentration of loratadine in the blood plasma without causing clinical manifestations or affecting the ECG.
Inducers of microsomal oxidation (phenytoin, ethanol, barbiturates, zixorin, rifampicin, phenylbutazone, tricyclic antidepressants) reduce the effectiveness of loratadine.
FDA approved in 2007
FDA approved in 2007
Trade names Alerza, Allertek, Atarax, Zincet, Zirtec, Zodak, Letizen, Parlazin, Cetirinax, Cetrin
Does not block cholinergic and serotonin receptors.
Has an antiallergic effect.
when used in therapeutic doses, it does not penetrate the BBB, and therefore does not cause any significant sedative effect.
Cetirizine affects both the early and late stages of the allergic reaction.
Indications for use of the drug CETRIN®
seasonal and chronic allergic rhinitis;
allergic conjunctivitis;
itching of various etiologies;
urticaria (including chronic idiopathic);
With angioedema (Quincke's edema).
The onset of effect after a single dose of 10 mg of cetirizine is 20 minutes (in 50% of patients) and after 60 minutes (in 95% of patients), lasting more than 24 hours. During a course of treatment, tolerance to the antihistamine effect of cetirizine does not develop. After stopping treatment, the effect lasts up to 3 days.
For adults and children over 6 years of age, the daily dose is 10 mg, for adults - in 1 dose, washed down with a small amount of water.
If renal function is impaired, a dose adjustment of the drug is required (as a rule, the dose is reduced by 2 times).
Drug interactions
To date, there is no data on the interaction of cetirizine with other drugs; however, caution should be exercised when prescribing the drug with sedatives.
