It is a drug that blocks H2 histamine receptors. H2-blockers of histamine receptors. Side effects of H2-histamine blockers

Blockade of H1 receptors prevents bronchospasm caused by histamine and hyperemia, swelling, and skin inflammation that occur during the development of an allergic reaction. itching Therefore, the indications for the use of H1-histamine blockers are are primarily allergic diseases (especially those occurring with type I allergic reactions) and various conditions accompanied by the release of histamine in the tissues: hay fever, allergies, urticaria, reactions to insect bites, angioedema, current dermatoses, reactions to blood transfusion, administration of radiocontrast agents, medicines etc. In addition, certain H1-histamine blockers have additional pharmacological effects, which are taken into account in the clinical use of B. g.r. Thus, dimebon, sequifenadine, cyproheptadine have an antiserotonin effect, which makes them preferable for skin dermatoses; phenothiazine derivatives have α-adrenergic blocking properties; many H1-histamine blockers, especially the first generation, exhibit the properties of anticholinergics as peripheral ones (which helps to weaken allergic reactions), and central action (for penetrating the BBB); they potentiate the effect on the central nervous system. alcohol, sleeping pills and a number of tranquilizers and themselves inhibit the central nervous system in a dose-dependent manner, which has expanded the indications for their use as sedatives and even hypnotics (diphenhydramine), as well as antiemetics, in particular for Meniere's disease, vomiting of pregnancy, air and seasickness(dimenhydrinate). Diphenhydramine, along with a central depressant, also has a local anesthetic effect; like promethazine, it is part of lytic mixtures used in anesthesiology.

In case of an overdose of H1-histamine blockers that affect the central nervous system, drowsiness, lethargy, muscle dystonia are observed, convulsions are possible, sometimes increased excitability (especially in children), sleep disorders; anticholinergic effects can manifest as dry mouth, increased intraocular pressure, visual disturbances, impaired gastrointestinal motility, and tachycardia. in acute poisoning with diphenhydramine or promethazine, anticholinergic effects are especially pronounced; There are often hallucinations, psychomotor agitation, seizures, a stuporous state or coma develops (especially in case of poisoning due to alcohol intake), acute respiratory and cardiovascular.

Side effects of H1-histamine blockers and contraindications to their use are determined by the properties of specific drugs. Means that significantly affect the central nervous system. (diphenhydramine, phenothiazine derivatives, oxatomide, etc.) are not prescribed to persons continuing activities that require concentration and maintaining the speed of reactions. During the period of treatment with drugs that depress the central nervous system, alcohol consumption is excluded and the dosage of simultaneously used antipsychotics, hypnotics and tranquilizers is reviewed. A number of second-generation drugs (astemizole, terfenadine, etc.) are characterized by an arrhythmogenic effect on the heart, associated with a prolongation of the QT interval on the ECG; they are contraindicated in persons with an initial prolongation of the Q-T interval due to the threat of developing ventricular tachyarrhythmias with possible sudden death. Drugs with a noticeable anticholinergic effect are contraindicated in angle-closure glaucoma. Almost all H1-histamine blockers are contraindicated for women during pregnancy and while breastfeeding.

Release forms and brief characteristics of the main H1-histamine blockers are given below.

Azelastine(allergodil) - 0.05% solution ( eye drops); nasal spray (1 mg/ml) 10 each ml in a bottle. In addition to its main action, it blocks the release of inflammatory mediators from mast cells. Used topically for allergic e (1 drop in each eye 3-4 times a day) and e (1 inhalation in each nasal passage 1-2 times a day). Side effects: local dryness of mucous membranes, bitterness in the mouth.

Astemizole(asmoval, astelong, astemisan, gismanal, histalong, stealert, stemiz) - tablets of 5 and 10 mg; suspension (1 mg/ml) for oral administration, 50 and 100 ml in bottles. It penetrates little through the BBB and exhibits almost no anticholinergic properties. After absorption, it is metabolized in the liver to form an active metabolite - desmethylastemizole; excreted primarily in bile; T 1/2 of astemizole reaches 2 days, desmethylastemizole 9-13 days. some macrolides and antifungal drugs can reduce the rate of metabolism of astemizole. Prescribed to patients over 12 years of age orally 10 mg 1 time/day ( maximum dose - 30 mg/day), children from 6 to 12 years old 5 mg/day, children from 2 to 6 years old - only in the form of a suspension at the rate of 0.2 mg/1 kg body weight 1 time/day; Duration of treatment is up to 7 days. Overdose and side effects: emotional disorders, paresthesia, convulsions, increased activity of liver transaminases, prolongation of the QT interval on the ECG, ventricular tachyarrhythmias; with prolonged use, an increase in body weight is possible. Contraindications: age under 2 years; extended QT interval on ECG, hypokalemia; severe liver dysfunction; pregnancy and lactation; simultaneous use of ketoconazole, intraconazole, olon, erythromycin, quinine, antiarrhythmics and other drugs that can prolong the QT interval.

Dimebon- tablets 2.5 mg(for children) and 10 mg. Its structure is similar to mebhydrolin; additionally exhibits antiserotonin properties; has a sedative and local anesthetic effect. Prescribed for adults: 10-20 mg up to 3 times/day. within 7-12 days.

Dimenhydrinate(Anauzin, Daedalon, Dramil, Emedil, etc.) - 50 tablets mg- complex salt of diphenhydramine (diphenhydramine) with chlortheophylline. It has a pronounced central, in particular antiemetic effect. It is used mainly to prevent and relieve symptoms of air and sea sickness, Meniere's disease, and bouts of vomiting. of different origins. Prescribed to adults: 50-100 orally before meals mg half an hour before boarding a plane or ship, and for therapeutic purposes in the same dose 4 to 6 times a day. In this case, anticholinergic effects (dry mouth, accommodation disorders, etc.) are possible, which can be eliminated by reducing the dose of the drug.

Dimetinden(fenistil) - 0.1% solution (drops for oral administration); retard tablets 2.5 each mg; retard capsules 4 each mg; 0.1% gel in tubes for application to affected areas of the skin. In addition to H 1 -histamine blocking, an antikinin effect is expected; has pronounced anti-edematous and antipruritic effects, exhibits weak sedative and anticholinergic properties (drowsiness and dry mouth are possible when used). Orally, patients over 12 years of age are prescribed 1 mg(20 drops) up to 3 times a day or retard tablets 2 times a day or retard capsules 1 time a day; daily dose for children under 1 G ode is 3-10 drops, from 1 to 3 years - 10-15 drops, from 3 to 12 years - 15-20 drops (in 3 doses). The gel is used 2-4 times a day.

Diphenhydramine(alledril, allergin, amidryl, benadryl, diphenhydramine, etc.) - tablets of 20, 25, 30 and 50 mg; 1% solution in ampoules and syringe tubes of 1 ml; “sticks” (50 each mg) on a polyethylene basis for insertion into the nasal passages for allergic rhinitis; candles of 5, 10, 15 and 20 mg. Inhibits the central nervous system, exhibits pronounced anticholinergic activity, incl. in the autonomic ganglia. Except allergic diseases, is additionally used as a hypnotic and antiemetic (in particular, for Meniere's syndrome), as well as for chorea and as part of lytic mixtures for premedication in anesthesiology. As an antiallergic drug for adults, 30-50 are prescribed orally mg 1-3 times a day; maximum daily dose 250 mg; 20-50 are administered intravenously (drip) and intramuscularly mg. Children: up to 1 G ode - 2-5 mg; from 2 to 5 years - 5-15 each mg; from 6 to 12 years - 15-30 each mg appointment. As a sleeping pill, adults are prescribed 50 mg for the night. Contraindications: angle closure, tic status, pyloroduodenal s, obstructive bowel movements Bladder, incl. with prostatic hypertrophy.

Quifenadine(fenkarol) - tablets of 10 (for children's practice), 25 and 50 mg. In addition to blocking H1-histamine receptors, it reduces the content of free histamine in tissues by activating diamine oxidase. It penetrates little through the BBB and in therapeutic doses does not have a noticeable sedative and anticholinergic effect. Prescribed orally after meals (due to the irritant effect on the mucous membranes) to persons over 12 years of age, 25-50 mg 2-4 times a day; children under 3 years old - 5 mg, from 3 to 7 years - 10 mg 1-2 times a day, from 7 to 12 years - 10-15 mg 2-3 times a day. The drug is well tolerated; Sometimes dry mouth and dyspeptic disorders are observed, which disappear when the dose is reduced.

Clemastine(angistan, rivtagil, tavegil, tavist),

Levocabastine(histimet) - 0.05% solution in bottles of 4 ml(eye drops) and in bottles of 10 ml in the form of an aerosol for intranasal use. Used for allergic conjunctivitis (1 drop in each eye 2-4 times a day) and ah (2 injections in each nasal passage 2 times a day). There is practically no resorptive effect; possible transient local irritation of the mucous membranes.

Loratadine(claritin, lomilan) - tablets 10 mg; suspension and syrup (1 mg/ml) in bottles. Prescribed orally 1 time per day: adults and children weighing more than 30 kg 10 each mg. Side effects: increased fatigue, dry mouth, nausea.

Mebhydrolin(diazolin, insidal, omeryl) - tablets of 50 and 100 mg, syrup 10 mg/ml. It penetrates little through the BBB and therefore practically does not inhibit the central nervous system. (weak sedative effect); exhibits anticholinergic properties. Prescribed orally for adults and children over 10 years of age, 100-300 mg/day (in 1-2 doses), children under 10 years old 50-200 mg/day Contraindications are the same as for diphenhydramine (diphenhydramine).

Oxatomide(tinset) - tablets 30 each mg. In addition to blocking H1-histamine receptors, it suppresses the release of mediators of allergy and inflammation from mast cells. Depresses central nervous system. Prescribed orally for adults 30-60 mg(elderly - 30 mg) 2 times a day; children weighing 15-35 kg- 15 each mg once a day, with body weight more than 35 kg- 30 each mg/day (in 1 or 2 doses). Side effects: drowsiness, weakness, fatigue, dry mouth, dyskinesia (in children), increased activity of liver transaminases, increased appetite with weight gain (when used in high doses). Contraindications: age under 6 years, pregnancy and breast-feeding child, active diseases and functional liver, simultaneous use of drugs that depress the central nervous system.

Promethazine(allergan, diprazine, pipolfen, etc.) - 25 tablets mg; 2.5% solution in ampoules of 2 ml (50 mg) for intramuscular or intravenous administration. Pronouncedly affects the central nervous system. (sedative and antiemetic effects, lowering body temperature), has a-adrenolytic as well as anticholinergic (peripheral and central) effects. In addition to allergic diseases, it is used for Meniere's disease (syndrome), seasickness and air sickness, chorea, ah, ah and ah with agitation and sleep disorders, in anesthesiology as part of lytic mixtures - to potentiate anesthesia, as well as the action of analgesics and local anesthetics. Prescribed orally for adults at 12.5-25 mg 2-4 times a day (maximum daily dose 500 mg); parenterally (for emergency indications, before and after surgical interventions) 50 mg(maximum daily dose 250 mg). Children aged 2 to 12 months. 5-7.5 are prescribed orally mg 2-4 times a day, from 1 year to 6 years - 7.5-12.5 mg 2-4 times a day, from 6 to 14 years - 25 mg 2-4 times a day. Side effects: drowsiness, less often psychomotor restlessness, photophobia, extrapyramidal disorders; increased body temperature, orthostatic arterial (with intravenous administration); dry mouth, dyspeptic disorders; with long-term use - deposits in the lens and cornea of ​​the eyes, menstruation disorders, glucose metabolism, sexual function. Contraindications: , arterial hypotension; angle-closure, obstructive bladder emptying disorders, incl. with prostate hypertrophy, pyloroduodenal s; pregnancy and breastfeeding period; simultaneous use of MAO inhibitors.

Sequifenadine(bicarfen) - tablets 50 each mg. Additionally, it blocks serotonin S1 receptors, which manifests itself in a pronounced antipruritic effect in case of edema dermatoses. Prescribed orally after meals for adults, 50-100 mg 2-3 times a day for 3-4 days (when the maximum effect is achieved), then switch to a maintenance dose - 50 mg 2 times a day. Tolerability of the drug is the same as quifenadine.

Setastin(Loderix, Loridex) - tablets 1 each mg. Its structure is similar to tavegil; additionally exhibits antiserotonin properties; penetrates the BBB, has a sedative, hypnotic and anticholinergic effect.

Terfenadine(bronal, histadine, caradonel, tamagon, teridine, tofrin, trexil) - tablets of 60 and 120 mg, syrup or suspension (6 mg/ml) for oral administration. The metabolism of the drug in the liver can be inhibited by macrolides and some antifungal drugs. Virtually no effect on central nervous system; capable of prolonging the QT interval per ECG, causing ventricular tachyarrhythmias with the likelihood sudden death; with prolonged use, an increase in body weight is possible. Prescribed 2 times a day for patients over 12 years of age, 60 mg, children from 6 to 12 years old - 30 mg appointment. Contraindications are the same as for astemizole.

Pheniramine(avil) - tablets 25 each mg; syrup for oral administration (in pediatrics); solution for injection (22.75 mg/ml) in ampoules of 2 ml. Has a sedative and anticholinergic effect. Usually prescribed 2-3 times a day for adults 25 mg, teenagers 12-15 years old - 12.5-25 mg, children - 7.5-15 mg. Contraindications are the same as for diphenhydramine.

Chloropyramine(suprastin) - tablets 25 mg; 2% solution for intramuscular or intravenous administration in ampoules of 1 ml. According to the effect on the central nervous system, peripheral, anticholinergic and side effects close to diphenhydramine. Adults are prescribed 25 orally mg 3-4 times a day. For severe allergic and anaphylactic reactions, administer 1-2 doses parenterally ml 2% solution. Contraindications are the same as for diphenhydramine.

Cetirizine(allercet, zyrtec, cetrin) - tablets 10 mg; 1% solution (drops for oral administration) in bottles of 10 ml; 0.1% suspension for oral administration in bottles of 30 ml. In addition to blocking H1-histamine receptors, it suppresses the migration of eosinophils and the release of mediators associated with the “late” (cellular) stage of the allergic reaction. In therapeutic doses, it has virtually no effect on the central nervous system. and does not have an anticholinergic effect. Adults and children over 12 years of age are prescribed 10 doses orally. mg/day (in 1-2 doses); children from 2 to 6 years old - 5 mg(10 drops) 1 time per day or 2.5 mg 2 times a day; children from 6 to 12 years old - 10 mg/day (in 2 doses).

Cyproheptadine(peritol) - tablets 4 each mg; syrup (0.4 mg/ml). It has a sedative, anticholinergic and strong antiserotonin effect with a pronounced antipruritic effect; stimulates appetite; inhibits hypersecretion of somatotropin in acromegaly and ACTH in Itsenko-Cushing syndrome. Used as for allergic diseases(especially for itchy dermatoses), and for migraines, anorexia, as well as as part of complex treatment for bronchial asthma, chronic e. Prescribed for adults 2-4 mg 3 times a day or once (for migraine); maximum daily dose 32 mg. The daily dose for children from 2 to 12 years is approximately 1 mg for every year of a child's life. In case of overdose in children, anxiety, hallucinations, ataxia, convulsions, facial hyperemia, mydriasis, collapse, coma are possible; in adults - lethargy, turning into stupor, coma; psychomotor agitation, convulsions, and rarely hyperthermia are possible. Contraindications are associated mainly with anticholinergic effects (glaucoma, prostate hypertrophy, etc.), which increase with the simultaneous use of tricyclic antidepressants. The drug is not prescribed to patients who continue to perform work that requires concentration and quick reactions.

N 2 - histamine blockers are used mainly in gastroenterology as means overwhelming secretory activity stomach, although histamine H2 receptors are also found in the myocardium, blood vessels, in T-lymphocytes, in mast cells, in the central nervous system.

There are H2-histamine receptor blockers of the first generation (cimetidine), second generation (nizatidine, ranitidine, etc.) and third generation (famotidine). By blocking H 2 -histamine receptors of the parietal (lining) cells of the stomach, they significantly reduce their basal secretion and secretion stimulated by food, histamine, pentagastrin and caffeine. Secretion stimulated by acetylcholine (carbocholine) decreases under their influence to a lesser extent, and cimetidine practically does not change it, because does not have a cholinolytic effect. By increasing the pH in the stomach, H2-histamine blockers reduce the activity of pepsin and generally reduce the importance of the peptic factor in the formation of ulcers and erosions of the stomach and duodenum, promoting their healing.

indications for the use of H 2 -histamine blockers: peptic ulcer of the stomach and duodenum (in the acute phase, with a complicated course, as well as for the prevention of exacerbations), Zollinger-Ellison syndrome, reflux esophagitis, acute and chronic (in the acute phase) cholestasis a) . Headache, dizziness, and transient mental disorders, leukocyte- and . Cimetidine inhibits the activity of cytochrome P-450 and a number of other microsomal liver enzymes involved in the metabolism and inactivation of various substances, incl. some medications (for example, indirect anticoagulants, diphenin, theophylline, diazepam), which can cause their “overdose” when used in normal doses. This drug stimulates the secretion of prolactin, inhibits the absorption of vitamin B12, leading to its deficiency, and has an antiandrogenic effect; with long-term use, impotence in men is possible (nizatidine also has this effect). When using ranitidine and famotidine, disorientation, aggressiveness, and hallucinations are possible. In addition, ranitidine can increase intraocular pressure in patients with glaucoma, slow down atrioventricular conduction and suppress the automaticity of cardiac pacemakers, causing bradycardia, sometimes asystole; Cases of alopecia have been reported with the use of famotidine.

Contraindications: age under 7 years, pregnancy and breastfeeding, significant dysfunction of the liver and kidneys, heart failure, simultaneous use of cytostatics.

The release forms and dosage of the main H 2 -histamine blockers are given below.

Nizatidine(axid) - capsules of 150 and 300 mg; concentrate for intravenous infusions 100 mg in bottles of 4 ml. For the treatment of exacerbation of peptic ulcer, 150 is prescribed orally mg 2 times a day or 300 mg 1 time at night; for preventive purposes - 150 mg 1 time at night. For intravenous infusion 100 mg drugs (4 ml) bred at 50 ml 0.9% sodium chloride solution or 5% glucose solution and administered over 15 min 3 times a day; for continuous infusion (at a speed of 10 mg/h) at 150 ml the above solutions are diluted 300 mg drug (12 ml).

Ranitidine(acidex, acylok-E, bezacid, histak, zantac, raniberl, ranitin, ranisan, ulcosan, etc.) - tablets of 150 and 300 mg; 1% and 2.5% solutions for intramuscular or intravenous administration in ampoules of 5 and 2, respectively ml(50 each mg). The use and dosage of the drug orally in adults for peptic ulcer disease are the same as for nizatidine; for Solinger-Ellison syndrome, the initial oral dose is 150 mg 3 times a day and can be increased to 600-900 mg/day To prevent Mendelssohn syndrome, 150 is prescribed mg the night before and 150 mg for 2 h before induction of anesthesia; with the onset of labor - 150 mg every 6 h. In case of acute gastrointestinal bleeding, the drug is administered intravenously or intramuscularly at 50 mg every 6-8 h. If it is necessary to use it for peptic ulcers in children, the daily dose orally (for 2 doses) is determined at the rate of 2 mg/kg body weight (but not more than 300 mg/day).

Roxatidine(roxan) - tablets of 75 and 150 mg. For peptic ulcers and reflux esophagitis, adults are prescribed 75 orally. mg 2 times a day or 150 mg 1 time at night. Long-term use may result in decreased libido. The drug is not recommended for children.

Famotidine(antodine, blockacid, gastrosidin, quamatel, lecedil, topcid, ulfamide, ulceran, famonit, famosan, famocid) - tablets of 20 and 40 mg; lyophilized dry substance for infusion 20 mg in bottles with the supplied solvent. For the treatment of peptic ulcer and reflux esophagitis, 20 doses are prescribed orally mg 2 times a day or 40 mg 1 time at night; for Solinger-Ellison syndrome - 20-40 mg every 6 h(maximum daily dose 480 mg). For jet intravenous administration, the contents of the bottle are diluted in 5-10 ml, for drip - 100 ml and 0.9% sodium chloride solution. The drug is not recommended for children.

Cimetidine(belomet, histodil, neutronorm, primamet, simesan, tagamet, etc.) - tablets of 200, 400 and 800 mg

Histamine H2 receptor blockers are still one of the most common medicines, which are used in the treatment of peptic ulcers. This is primarily due to their pronounced antisecretory properties, but in addition, H2 blockers suppress basal and stimulated production of pepsin, increase the production of gastric mucus, increase the synthesis of prostaglandins in the gastric mucosa, increase the secretion of bicarbonates, improve microcirculation in the mucous membrane, and normalize the motor function of the stomach and duodenum. A positive effect of H2 blockers on the normalization of ultrastructural parameters of the gastric epithelium was also discovered.

The first drugs of this class were synthesized in 1972, but they had a large number of side effects, in particular, toxic effects on the bone marrow. In the same time cimetidine the first drug to be widely used clinical practice, also has serious side effects. Thus, the administration of this drug stimulates the secretion of prolactin, which can cause the appearance of gynecomastia; There is a decrease in the level of insulin in the blood plasma, which causes the appearance of reduced glucose tolerance while taking cimetidine. Cimetidine also blocks peripheral receptors of male sex hormones, it can cause an increase in testosterone in the blood, have a hepatotoxic effect (decreased blood flow in the liver, increased levels of transaminases), blocking the cytochrome P450 system, increasing the level of creatinine in the blood, damage to the central nervous system, hematological changes, cardiotoxic effects, immunosuppressive effects.

Changes in intragastric pH in patients peptic ulcer duodenum after a single dose of 200 mg of cimetidine orally was studied by V. Matov. The onset of the pH response was observed on average 45 minutes after taking the cimetidine tablet, the effect peaked at 135 minutes and lasted for 3.5 hours. During the action of the drug in the body of the stomach, the pH was maintained at a level above 3.0 units (i.e., at a slightly acidic level necessary for the healing of gastric and duodenal ulcers), in the antrum above 5.0 units for 2 hours 45 minutes. The effectiveness of cimetidine largely depends on the initial level of acidity: the activity of the drug was significantly higher in patients with normal acidity (8 people) and compensated hyperacidity (11 people) compared to patients who had decompensated hyperacidity (11 people).

In case of decompensated hyperacidity, the intragastric pH exceeded 3.0 units in the body of the stomach for only 0.5 hours, and 5.0 units in the antrum for 1 hour. In the remaining patients, it was possible to maintain the pH in the stomach at these levels for 3.5 hours. In another study, taking 1 tablet (200 mg) of cimetidine caused an increase in intragastric pH in patients with duodenal ulcer after 30 minutes, reaching a maximum value of 8.26ｱ0.77 units after 90 minutes. The pH level remained alkaline for 2.5 hours.

While taking cimetidine at a dose of 8,000–1,000 mg per day, scarring of duodenal ulcers was observed in 78% of patients after 4 weeks. The use of cimetidine in patients with duodenal ulcer causes scarring of ulcers after 3 weeks in 58.8% of patients, the average time for scarring is 27.3ｱ3.4 days.

Nizatidine, when taken once at a dose of 300 mg at night, caused a significant increase in the average pH of the body of the stomach in patients with duodenal ulcers both during the night period and over a full day compared to the record before treatment.

The severity of the effect of H2 blockers is influenced by the time of their administration and dependence on food intake. With relatively early administration of nizatidine and an early dinner (18.00), significantly more high level pH in 21 hours (2.50 units) compared with early administration of the drug and late dinner (21.00).

Reception ranitidine 150 mg 2 times a day helps restore spontaneous nighttime alkalization of the stomach in patients with peptic ulcer disease. Taking H2 blockers in doses higher than average (for example, 300 mg of ranitidine 2 times a day), allows you to achieve an antisecretory effect comparable to that of omeprazole, which confirms the relationship between the severity of antisecretory and antiulcer effects. It has been shown that in smoking patients, H2 blockers are less effective in suppressing the secretion of hydrochloric acid.

The average time for disappearance of abdominal pain when taking 300 mg of ranitidine per day is 2.6ｱ0.5 days. Taking 300 mg of ranitidine per day, according to various authors, provides scarring of duodenal ulcers in 4660% of patients after 2 weeks of treatment and in 7489% after 4 weeks.

Famotidine (Quamatel) belongs to the 3rd generation of histamine H2 receptor blockers. This drug may be used in patients with renal impairment (at lower doses according to the degree of reduction in creatinine clearance).

It is known that famotidine is superior in activity to ranitidine, roxatidine and cimetidine. A 5 mg dose of famotidine is equivalent to 300 mg of cimetidine. The effect of cimetidine, ranitidine and famotidine occurs at approximately the same time after administration, however, the duration of action of famotidine is significantly longer than cimetidine. After intravenous administration of 20 mg famotidine, the half-life of the drug is 3.8 hours. Wide Application The benefit that famotidine finds in modern clinical practice is due to the fact that this drug has a very small number of side effects. Famotidine does not have a hepatotoxic effect, does not block the cytochrome P450 system, does not increase plasma creatinine levels, does not penetrate the blood-brain barrier and does not cause neuropsychiatric disorders. When taking 40 mg of famotidine daily for 4 weeks, there is no change in the levels of prolactin, testosterone, follicle-stimulating and luteinizing hormones. After oral administration of 40 mg of famotidine or intravenous administration of 20 mg of the drug, there is no change in the level blood pressure, heart rate and ECG patterns. Taking famotidine at a dose of 40 mg twice a day does not disrupt the gastric emptying process and does not affect pancreatic function. As evidenced by H.G. Dammann, based on data on the use of famotidine at a dose of 40 mg/day in 10,814 patients in Germany, bloating occurs in only 1.17% of cases, constipation in 0.20%, diarrhea in 0.31%, skin reactions in 1. 12 %.

In healthy volunteers, a single dose of famotidine at a dose of 5 to 20 mg caused a decrease in basal acid formation by 94 and 97%, respectively (J.L. Smith et al. and R.W. McCallum et al.). The production of hydrochloric acid after stimulation with pentagastrin decreased accordingly by 4190%. Famotidine at a single dose of 10 and 20 mg had a significantly more pronounced inhibitory effect on the production of hydrochloric acid in the stomach compared to cimetidine at a dose of 300 mg (p<0,05). По свидетельству R. Ryan , пероральный прием 20 и 40 мг фамотидина обеспечивает эффективный контроль секреции соляной кислоты в течение 9,5 часов. Прием 20 мг фамотидина в 20 ч на ночную секрецию соляной кислоты у 10 здоровых лиц вызвал снижение продукции соляной кислоты по сравнению с приемом плацебо на 93,8 % (p<0,01), которое сохранялось в течение 12 часов (Y. Fukuda и соавт. 1987). После перорального приема 1 таблетки фамотидина (40 мг), покрытой оболочкой, повышение рН более 3,5 ед в теле желудка у здоровых добровольцев наступает через 56,5 мин, после этого происходит стабилизация рН на протяжении 11 часов .

Studies that were performed using intravenous injections of famotidine also showed the high effectiveness of this drug. However, in the study by L.S. Welage (1988) observed a significantly higher effectiveness of famotidine at a dose of 20 mg twice a day compared with cimetidine at a dose of 300 mg 4 times a day when administered intravenously in 42 patients in the intensive care unit (p<0,001). В работе A. AlQuorain и соавт. (1994) показана более высокая эффективность фамотидина по сравнению с ранитидином при внутривенном введении больным, находящимся в критическом состоянии. При введении 20 мг фамотидина каждые 12 часов уровень рН желудочного сока был достоверно выше (p<0,05), чем при введении 50 мг ранитидина каждые 8 часов.

When 20 mg of famotidine was administered intravenously to healthy subjects, the onset of action of the drug was observed on average after 36.3ｱ11.9 minutes if the injection was carried out at 14.00, and after 53.6ｱ22.3 minutes when administered at 20.00. The duration of action of the drug was 6.0ｱ1.1 hours and 11.4ｱ1.6 hours, respectively. Data obtained from a double-blind study using intravenous drip of famotidine at a dose of 3.2 or 4 mg/hour show the high effectiveness of this drug both during periods between meals and at the height of digestion .

Famotidine is clinically effective. Thus, in patients with peptic ulcer, when taking the drug at a dose of 40 mg/day, abdominal pain disappears on average after 2.4ｱ0.8 days. When using Kvamatel in a group of patients with peptic ulcer (11 patients with duodenal ulcer, 3 patients with gastric ulcer) at a dose of 40 mg once at night, a decrease in abdominal pain was observed on average after 3.9 days, disappearance after 6.8 days. In two patients, pain was not completely relieved within 14 days of therapy. Within a period of up to 2 weeks, the ulcers healed in 13 patients (93%). The use of famotidine at a dose of 40 mg/day as monotherapy in patients with duodenal ulcer causes the disappearance of abdominal pain after an average of 7.8ｱ4.6 days, palpation pain after 9.6ｱ5.3 days, scarring of ulcers after 20 .5ｱ2.2 days (terms are significantly shorter compared to the control group receiving therapy with anticholinergics, antacids, reparants). Taking famotidine at a dose of 40 mg/day allows you to achieve scarring of duodenal ulcers within 4 weeks.

in 7995% of patients, within 6 weeks. at 9597%. According to other data, famotidine at a dose of 40 mg/day caused scarring of duodenal ulcers in 86.3% of patients after 4 weeks of administration. According to A.A. Sheptulin, taking H2 blockers in medium doses (ranitidine 300 mg/day or famotidine 40 mg/day) causes scarring of duodenal ulcers within 4 weeks in 7593% of patients with duodenal ulcer, while no differences in the therapeutic effectiveness of the two drugs are observed.

Maintenance therapy using a single dose of H2 blocker at night can be successfully used for prevention of relapse of peptic ulcer or to relieve symptoms of hyperacidity . Within 1 year, symptoms of exacerbation develop in 20% of patients compared to 60-70% of patients who did not receive treatment. Maintenance use of H2 blockers significantly reduces the incidence of complications of peptic ulcer disease, in particular, significantly reduces the risk of recurrent bleeding. At the same time, it should be taken into account that when treatment is discontinued, peptic ulcer disease recurs with the same frequency as in patients who did not receive treatment (Fig. 1). In this regard, patients are currently undergoing eradication of the infection. H. pylori(including the use of H2 blockers), which gives a lasting anti-relapse effect. Interestingly, according to some researchers, the use of famotidine in eradication therapy regimens is as effective as the use of omeprazole.

Rice. 1. Recurrence of duodenal ulcer with different management tactics (J.H. Walsh, R.Fass, 1997)

The effectiveness of H2 blockers varies in different groups of patients, in particular, smoking is a serious factor reducing the effectiveness of these drugs. Taking nizatidine 300 mg/day in patients with duodenal ulcer (21 people) and stomach (4) led to the disappearance of abdominal pain on average after 5.8 ± 0.4 days (from 2 to 12), while in non-smokers Patients had a faster disappearance of pain - 3.2±0.2 (from 1 to 4 days) than in smokers - 7.6±0.6 (from 5 to 12 days). Thus, smoking not only affects the occurrence of peptic ulcers, but also impairs the effectiveness of therapy. As the data shows The RUDER study group , factors determining a higher frequency of relapses of duodenal ulcer during maintenance use of H2 blockers (ranitidine at a dose of 150 mg per day) are the presence of erosions outside the localization area of ​​the healed ulcer, current or past smoking, and some others.

Unfortunately, there is a group of patients resistant to histamine H2 blockers (just as there are patients, for example, resistant to proton pump inhibitors). Resistance to H2 blockers is observed according to clinical data in 15-25% of all patients with peptic ulcer disease. According to the drug test with cimetidine with intragastric pHmetry, this was observed in 11.5% of patients with duodenal ulcer and chronic gastroduodenitis.

When treating peptic ulcers, most patients need to take H2 blockers 1 or 2 times a day. However, conditions that are accompanied by more severe hyperacidity, such as Zollinger-Ellison syndrome, require more frequent administration every 4 hours.

Frequent use of histamine H2 receptor blockers in patients with reflux esophagitis brings their effectiveness closer to that of omeprazole. H2 blockers can significantly reduce heartburn, although endoscopic signs of esophagitis subside only in 60% of patients after 12 weeks of therapy. The use of H2 blockers for reflux esophagitis is on par with cisapride monotherapy in terms of effectiveness and can be recommended in patients with mild esophagitis. In addition, the addition of H2 blockers in the evening to proton pump inhibitor therapy allows for better control of nocturnal symptoms of gastroesophageal reflux disease.

H2 blockers are used in the treatment of patients with chronic pancreatitis, since inhibition of gastric secretion reduces the release of secretin by the duodenal mucosa and, as a result, the volume of pancreatic secretion decreases and intraductal hypertension decreases. For this purpose, double doses of H2 blockers are used in doses used to treat peptic ulcers (for example, 20 mg of famotidine in the morning + 40 mg in the evening).

H2histamine receptor blockers are widely used in rheumatology to prevent the formation of drug-induced ulcers of the duodenum and stomach (in higher doses) in patients taking non-steroidal anti-inflammatory drugs. However, they are more effective than antacids, sucralfate and prostaglandins (misoprostol).

Thus, despite the emergence of new, more powerful antisecretory drugs, such as proton pump inhibitors, H2 blockers remain a widespread group of drugs that are used in many areas of gastroenterology, primarily due to their very attractive price/effectiveness ratio.

Literature:

1. Damianov B., Matov V., Zheinova D. Ultrastructural mechanisms on the antiacid effect on biomet in patients with duodenal ulcers // Vutr.Boles. 1985. v.24. No. 1. With. 2230.

2. Degtyareva I.I., Semeunovich S., Kharchenko N.V. and others. Possibilities of using the modern antisecretory drug omeprazole // Klin. honey. 1994. t. 72. No. 6. P.3840.

3. Dedov I.I., Shilin D.E., Arefieva O.A. Endocrine effects of cimetidine // Klin. honey. 1993. t. 71. No. 2. P. 1116.

4. Matov V. Effect of a single dose of simetidine ｫFarmakhimｻ pH value on ostomy // Vutr. Boles. 1987. v.26. No. 3. With. 5056.

5. Myagkova L.P., Golochevskaya V.S., Lapina T.L. H2histamine receptor blockers of the 23rd generation in the treatment of peptic ulcer // Klin. pharmacology and therapy. 1993. No. 2. With. 3335.

6. Ogurtsov P.P., Zharkov O.B., Moiseev V.S. Comparison of the effectiveness of ulfamide and enprostil in the treatment of peptic ulcer // Klin. pharmacology and therapy. 1993. No. 2. With. 2225.

7. Serebryanskaya M.V., Masenko V.P. Dynamics of prostaglandin E content in patients with duodenal ulcer with various types of treatment // Klin. honey. 1993. v.71. No. 71. P. 4547.

8. Smagin V.G., Minushkin O.N., Bulgakov S.A. and others. Experience in the treatment of duodenal ulcer with H2histamine receptor blockers / Ter. archive. 1986. volume 58. No. 2. S. 2530.

9. Zimmerman Ya.S., Syman L.N., Golovanova E.S. Experience of objective assessment of the action of cimetidine, a histamine H2 receptor blocker, in patients with duodenal ulcer. // Ter. archive. 1986. t. 58. No. 2. P. 3135.

10. Sheptulin A.A. Modern antisecretory drugs in the treatment of peptic ulcer // Klin. honey. 1994. t. 72. No. 1. p. 1215.

11. Armstrong D., Arnold R., Classen M. et al., The RUDER Study group RUDER a prospective, two-year, multicenter study of risk factors for duodenal ulcer relapse during maintenance therapy with ranitidine // Dig Dis Sci. 1994. vol 39. P. 14251433.

12. Bianco A., Cagossi M., Piraccini R., Greco A.V. Twenty four hour intragastric pH metry: H2receptor antagonist restoration of nightly gastric spontaneous alkalinization in duodenal ulcer healing. // Riv. Eur. Sci. Med. Farmacol. 1992. vol.14. ?5. P. 281291.

13. Dammann H.G. et al. Compatibility profile of famotidine. In Famotidine heute (Dammann H.G. et al., eds). SpringerVerlag, Berlin. 1989, P. 93102.

14. Duroux P., Emde C., Bauerfeind P. et al. Early evening nizatidine intake with a meal optimizes the antisecretory effect. // Aliment. Pharmacol. Ther. 1993. Feb; ?7(1). P. 4754.

15. Fiorucci S., Santucci L., Morelli A. Effect of omeprazole and high doses of ranitidine on gastric acidity and gastroesophageal reflux in patients with moderatesevere esophagitis // Am. J. Gastroenterol. 1990. ?85 (11) P. 14581462.

16. Gladziwa U., Wagner S., Dakshinamurty K.V. et al. Intragastric longterm pHmetry in hemodialysis patients: A study with famotidine. // Clin. Nephrol. 1991. Aug; ?36 (2). P. 97102.

17. Gladziwa U., Wagner S., Dakshinamurty K.V. et al. Pharmacokinetics and pharmacodynamics of famotidine in patients with reflux oesophagitis. //Eur. J. Clin. Pharmacol. 1993. ? 44(4). P. 357360.

18. Licht H., Lemaire M. Lansoprasole versus ranitidine in duodenal ulcer (DU): a French multicenter study // Gastroenterology. 1992. vol.98. A78.

19. Londong W., Barth H., Damman H.G. et al. Doserelated healing of duodenal ulcer with the proton pump inhibitor lansoprasole // Aliment. Pharmacol. Ther. 1991. vol. 5. P. 245254.

20. Loser C., Burlage M., Folsch U.R. Einfluss von Ranitidin und Famotidin auf das intragastrale pHProfil von gesunden Probanden. Randomisierte CrossoverPrufung mit RanitidinBrausetabletten (300 mg) versus FamotidinFilmtabletten (40 mg). // Arzneimittelforschung. 1994. May?44 (5). P. 626629.

21. Merki H.S., Witzel L., Walt R.P. et al. Double blind comparison of the effects of cimetidine, ranitidine, famotidine and placebo on intragastric acidity in 30 normal volunteers // Gut. 1988, N29. P.8184.

22. Ryan R. Clinical pharmacology of phamotidine: Summary of data from the United States // Ital. J. Gastroenterology. 1984. ?16. P. 171174.

23. Savarino V., Mela G.S., Zentilin P. et al. Lack of gastric acid rebound after stopping a successful shortterm course of nizatidine in duodenal ulcer patients. //Am. J. Gastroenterol. 1991. vol.86. ?3. P. 281284.

24. Xue S, Katz PO, Banerjee P, Tutuian R, Castell DO. Bedtime H2 blockers improve nocturnal gastric acid control in GERD patients on proton pump inhibitors. Aliment Pharmacol Ther 2001 Sep;15(9):13516

25. Hsu CC, Chen JJ, Hu TH, Lu SN, Changchien CS. Famotidine versus omeprazole, in combination with amoxycillin and tinidazole, for eradication of Helicobacter pylori infection. Eur J Gastroenterol Hepatol 2001 Aug;13(8):9216

Histamine H2 receptor blockers are among the most common antiulcer drugs currently used. Several generations of these drugs have been used in clinical practice. After cimetidine, which for a number of years was the only representative of histamine H2 receptor blockers, ranitidine, famotidine, and a little later - nizatidine and roxatidine were sequentially synthesized. The high antiulcer activity of histamine H2 receptor blockers is due, first of all, to their ability to reduce the production of hydrochloric acid.

Cimetidine preparations

Histamine H2 receptor blocker for the treatment of stomach ulcers: Histodil

The active ingredient is cimetidine. Suppresses the production of hydrochloric acid, both basal and stimulated by histamine, gastrin and acetylcholine. Reduces pepsin activity. Indicated for the treatment of gastric ulcers in the acute phase. Available in the form of tablets of 200 mg and in the form of a solution for injection of 200 mg in an ampoule (2 ml).

Histamine H2 receptor blocker for the treatment of stomach ulcers: Primamet

The company's original drug, the active ingredient of which is cimetidine. Primamet tablets are intended for those who suffer from high acidity of gastric juice. The use of conventional hydrochloric acid neutralizers in most cases brings only temporary relief. Primamet acts more effectively - it does not neutralize excess hydrochloric acid, but affects the secretory cells of the stomach, preventing its excessive formation. Thus, the acidity of gastric juice decreases for a long period of time, stomach pain and disorders associated with indigestion disappear. Within an hour after taking one tablet of Primamet, the discomfort and pain associated with increased acidity of gastric juice are completely eliminated. Available in 200 mg tablets.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Cimetidine

Belongs to the group of antiulcer drugs that reduce the activity of the acid-peptic factor. The drug suppresses the production of hydrochloric acid and pepsin. It is used both in the exacerbation phase of peptic ulcer disease and for the prevention of recurrent gastric ulcers. Cimetidine is available in the form of film-coated tablets of 200 mg.

Ranitidine preparations

Histamine H2 receptor blocker for the treatment of stomach ulcers: Gistak

Gold standard in the treatment of gastric ulcers and other acid-peptic disorders. It has a number of advantages: a high percentage of cure for peptic ulcers, quick and lasting relief from pain, the possibility of combining with other drugs for the treatment of stomach ulcers, the possibility of long-term prevention of relapses, the absence of side effects even with long-term use, does not affect the liver, does not cause impotence and gynecomastia. The effect of a single dose lasts for 12 hours. After taking Gistak in the form of effervescent tablets, the effect is more pronounced and occurs earlier. The drug prevents the reflux of gastric contents into the esophagus. Eating does not affect the absorption of the drug. The maximum concentration is achieved when taken orally after 1-2 hours. Gistak is a drug with high safety. Histac is the only ranitidine that exists in a plain, effervescent form. Available in the form of film-coated tablets of 75, 150 and 300 mg; “Effervescent” tablets of 150 mg and in ampoules for injection of 50 mg - 2 ml.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Zantac

A specific fast-acting blocker of histamine H2 receptors. Zantac is the number one drug in the treatment of stomach ulcers. It is highly effective in treatment, guaranteed rapidity of analgesic action, complete safety during long-term use, and significantly improves the patient’s quality of life. Zantac suppresses the production of gastric juice, reducing both the volume and content of hydrochloric acid and pepsin (aggressive factors). The duration of action after a single oral dose is 12 hours. The maximum concentration in blood plasma after intramuscular administration is achieved in the first 15 minutes after administration. Available in the form of tablets of 150 and 300 mg; film-coated tablets, 75 mg; effervescent tablets 150 and 300 mg; solution for injection 25 mg in 1 ml in ampoules of 2 ml.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Ranitidine-Acri

The main drug in the treatment of peptic disorders. Belongs to the group of second generation histamine H2 receptor blockers and is the most used and reliable drug in the treatment and prevention of peptic disorders associated with peptic ulcer disease. The drug significantly reduces the production of hydrochloric acid and reduces the activity of pepsin. Ranitidine has a long-lasting effect (12 hours) with a single dose. Easy to use and well tolerated by patients. Available in the form of tablets of 0.15 g.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Kvamatel

III generation H2-histamine receptor blocker. Kvamatel is an antiulcer drug whose active ingredient is famotidine. Suppresses the production of hydrochloric acid and reduces the activity of pepsin. Convenient to use - after oral administration, the effect of the drug begins after 1 hour and lasts 10-12 hours. The drug is widely used in the treatment of stomach ulcers. Available in the form of film tablets of 20 and 40 mg, lyophilized powder for injection in bottles complete with a solvent of 20 mg.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Lecedil

III generation H2-histamine receptor blocker. Lecedil is an original development of a pharmaceutical company, the active ingredient of the drug is famotidine. Lecedil is a powerful blocker of hydrochloric acid production and also reduces the activity of pepsin. After oral administration, the drug is quickly absorbed from the gastrointestinal tract. The maximum concentration of the drug in the blood plasma is achieved 1-3 hours after oral administration. The duration of action of the drug after a single dose depends on the dose and ranges from 12 to 24 hours. Lecedil can be used both for the treatment and for the prevention of exacerbations of peptic ulcer disease. Available in the form of tablets containing 20 and 40 mg of famotidine.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Ulfamide

The company's original drug. Ulfamide provides rapid improvement in the symptoms of stomach ulcers, cures and prevents recurrence of ulcers. The active ingredient of the drug is famotidine. Famotidine was the first H2-receptor blocker whose dosage schedule allowed most patients to take it only once a day. The effectiveness of Ulfamide is significantly higher than the effectiveness of I and II generation H2 receptor blockers. Ulfamide blocks gastric secretion at night and has a maximum effect on secretion during the day. Available in tablets of 40 and 20 mg.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Ulceran

A drug famotidine. Selective blocker of H2-histamine receptors of the third generation. Causes a pronounced suppression of all phases of gastric secretion (hydrochloric acid and pepsin), including basal and stimulated (in response to gastric distension, exposure to food, histamine, gastrin, pentagastrin, caffeine and, to a lesser extent, acetylcholine), suppresses nocturnal gastric secretion juice It has a long-lasting effect (12-24 hours), which allows it to be prescribed 1-2 times a day. Unlike cimetidine and ranitidine, it does not inhibit microsomal oxidation associated with cytochrome P450, therefore it is safer with respect to drug interactions, as well as in patients with concomitant diastolic hypertension, heart failure with hyperaldosteronism and diabetes mellitus with excessive secretion of somatotropic hormone. Ulceran does not have serious central side effects, and therefore is more preferable in patients with diseases of the nervous system and in elderly patients. Due to the lack of antiandrogenic effects, it is considered as a first-line drug for adolescents and young men. Ulceran is successfully used as monotherapy to treat stomach ulcers. Effective for Zollinger-Ellison syndrome, reflux esophagitis, symptomatic ulcers. The drug has a wide index of therapeutic action. Due to its high safety, it is approved in a number of countries for over-the-counter use to eliminate symptoms of digestive disorders in adults. It is possible to prescribe the drug in pediatric practice. Available in tablets containing 20 and 40 mg of active substance.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Famosan

III generation H2-histamine receptor blocker. Famosan is the best choice in the treatment of stomach ulcers. The active substance of the drug is famotidine. The drug has a powerful antisecretory effect, reduces the aggressiveness of gastric juice, causes a dose-dependent suppression of hydrochloric acid production and a decrease in pepsin activity, which creates optimal conditions for ulcer scarring. Famosan does not cause side effects typical of first generation H2-histamine receptor blockers. In addition, the drug does not interact with androgens and does not cause sexual disorders. Can be prescribed to patients with concomitant liver diseases. Famosan can be used both for treatment and for the prevention of exacerbations. Available in the form of film-coated tablets of 20 and 40 mg.

Histamine H2 receptor blocker for the treatment of stomach ulcers: Famotidine

III generation H2-histamine receptor blocker. Famotidine- a highly selective antiulcer drug that effectively reduces the volume and acidity of gastric juice and pepsin production. It has a more pronounced therapeutic effect compared to other drugs. Famotidine has a wide therapeutic dose range. It is the drug of choice for the treatment of gastric ulcers in alcoholics. It is possible to combine Famotidine with other drugs. Taking the drug does not affect the metabolism of androgens (male sex hormones). Available in the form of film-coated tablets of 20 and 40 mg.

Histamine H2 receptor blocker for the treatment of gastric ulcers: Famotidine-Acri

Antiulcer drug, third generation H2-histamine receptor blocker. The drug effectively reduces the production of hydrochloric acid. Convenient to use - for stomach ulcers it is used once a day, the duration of action of the drug with a single dose depends on the dose and ranges from 12 to 24 hours. Famotidine-Acri has the fewest side effects. Available in the form of film-coated tablets of 20 mg.

Roxatidine preparations

Histamine H2 receptor blocker for the treatment of stomach ulcers: Roxane

The active substance is roxatidine. The drug significantly suppresses the production of hydrochloric acid by the cells of the gastric mucosa. After oral administration, it is absorbed from the gastrointestinal tract. Concomitant food intake, as well as antacid medications, do not affect the absorption of Roxane. Available in the form of retard film-coated tablets, 75 mg, and retard forte film-coated tablets, 150 mg.

H2 histamine receptor blockers are drugs that are used to treat the digestive system for diseases associated with an acid-dependent condition.

The mechanism of action of h2 blockers is based on the fact that the drug, entering the stomach, stops the functioning of the mucous membrane, thereby reducing the acidity level of gastric juice.

All histamine receptor blockers are antiulcer drugs.

Description

Depending on the disease and the form of the disease, the doctor prescribes the remedy that will best help the patient.

Pharmacokinetic characteristics

Comparative characteristics

Cemitidine

This drug is well absorbed from the digestive organs. The action begins 1-2 hours after administration. The medicine is taken orally or parenterally, and the time of action and effect do not differ much depending on the method of administration. Active substances penetrate the barrier and may end up in milk or placenta. Therefore, during pregnancy and breastfeeding, taking the drug is prohibited.

Residual substances are excreted by the kidneys within 24 hours.

Ranitidine

The bioavailability of the drug when taken orally is at least 50%. When using tablets, the maximum effect occurs after 2 hours; If you take an effervescent tablet, the effect will occur within 1 hour. Half of the substances are eliminated 2-3 hours after administration. The rest will come a little later. Penetrates into breast milk and placenta.

Famotidine

It is not completely absorbed into the stomach, only 40-45%, and has approximately 15% protein binding. The maximum effect occurs 1-3 hours after administration, depending on the dose and the specific case. The drug acts on histamine receptors for 10-12 hours. Excreted from the body by the kidneys.

Nazatidine

An antiulcer medicine that blocks the receptors and reduces the production of hydrochloric acid. It is absorbed quite quickly and begins to act within 30 minutes after administration. About 60% of substances are excreted unchanged in the urine.

Indications and contraindications

The doctor prescribes h2 receptor blockers if the patient needs to be treated for the following diseases:

• Stomach and intestinal ulcers.
• Severe damage to the mucous membrane of the esophagus.
• Gastroesophageal reflux.
• Zollinger-Ellison syndrome.
• Mendelssohn's syndrome.
• For the prevention of ulcers and pneumonia.
• If the patient has internal bleeding of the digestive organs.
• For pancreatitis.

Contraindications for use:

• Sensitivity to the components included in the composition.
• Cirrhosis of the liver.
• Kidney diseases.
• Pregnancy and lactation.
• Age up to 14 years.

Before prescribing medications from this group, the doctor must make sure that the patient does not have diseases that can be masked by taking h2 histamine receptor blockers. Such diseases include stomach cancer, so the possibility of its presence must be excluded.

Since histamine blockers are powerful drugs in the treatment of the digestive system, they have their own side effects, if they appear, you need to stop taking the medication.

Side effects:

• Headache and dizziness.
• Lethargy, drowsiness, hallucinations.
• Heart problems.
• Liver dysfunction.
• Acute allergic reaction.
• Increased creatine levels in the blood.
• Impotence.
• Other problems.

The use of Famotidine may cause problems with stool: diarrhea or constipation.

Despite the quality and effectiveness of medicines in this group, they are inferior to more modern medicines, such as. Nevertheless, for economic reasons, the prescription of H2 histamine receptor blockers continues, the drugs of which are cheaper than inhibitors.

Drugs that block histamine H2 receptors are considered obsolete drugs. In medicine, there are 2 types of drugs that reduce the production of histamine receptors:

• Proton pump inhibitors.
• H2 blockers.

Taking the first drugs is not addictive, and they can be taken during long-term therapy. The second type, when taken repeatedly, reduces the effectiveness of the action, so doctors do not prescribe them for more than one short course.

Resistance to H2 blockers

Not all patients are suitable for this type of medication. In 1-5% of patients, no obvious changes in health status were revealed during treatment and examination. This happens extremely rarely, but even if increasing the dose of the drug does not produce results, the only way to continue treatment is to completely change the drug.

Cost of drugs

• Ranitidine 300 mg costs from 30 to 100 rubles per package.
• Famotidine - a course of treatment for 3 weeks will cost the patient from 60 to 140 rubles.
• Cimetidine - the cost of medications for a full course of treatment is from 43 to 260 rubles.

All types of h2 histamine receptor blockers are inexpensive, everyone can afford them, but you should not select the medication yourself. To choose a medicine, you need to consult a doctor. The effect of taking the right medicine is positive. In most cases, it is possible to achieve, if not a complete cure, then to stop the attack, which helps patients begin full treatment.

Story

The creation of drugs of this type dates back to 1972, when the English scientist James Black synthesized and tried to study histamine molecules. The first medicine that was created was Burimamid. It turned out to be useless, and research continued.

After this, the structure was slightly changed and Metiamide was obtained. The drug has undergone studies on its effectiveness, but its toxicity exceeded acceptable levels.

The next drug was Cimetidine, despite the fact that it is a strong medicine, it has a large number of side effects. Therefore, experts have developed more modern medications that have virtually no side effects.

The second generation of H2 blockers includes Ranitidine. It turned out to be even more effective and safe for patients.

The next drug in this group was Famotidine. There are 4th and 5th generation histamine receptor blockers, but doctors more often prescribe Ranitidine and Famotidine: they best cope with acidity in the gastric juice. You can take Rinitidine once a day, preferably before bed, the drug helps well and is relatively inexpensive.

Another group of medications for the treatment of heartburn are H2-histamine receptor blockers. Until recently, namely the eighties of the 20th century, these were the drugs of choice not only for isolated heartburn, but also for many diseases of the digestive system. But the need for multiple doses of these drugs, pronounced side effects and the emergence of more modern drugs have pushed H2-blockers into the background, practically replacing them from the line of essential drugs for diseases of the gastrointestinal tract.

Is there a need to prescribe this group of drugs today? Perhaps they have been unreasonably forgotten? Let's figure it out.

Mechanism of action of histamine H2 receptor blockers

Medicinal substances belonging to the group of H2-histamine receptor blockers have been improved over the course of a century. Currently, they have been known for 5 generations. Before the advent of proton pump inhibitors (PPIs), which include Omeprazole, eliminating heartburn was a matter of almost all H2 blockers.

H2 blockers are prescribed primarily for any diseases of the digestive system accompanied by increased acid production.

They also reduce gastric acidity, like PPIs, but through different mechanisms. H2 blockers primarily block the production of histamine (this is a mediator or accelerator of many reactions in our body, specifically in this case it stimulates the production of gastric juice). By slowing down this process, blockers simultaneously reduce the release of pepsin (an enzyme that breaks down proteins) and increase the synthesis of gastric mucus (that part of the gastric juice that protects the mucous membrane from the harmful effects of hydrochloric acid). They also inhibit stimulated acid (which is produced under the influence of incoming food).

Prescribing drugs from the H2-blocker group for a long period can lead to one unpleasant effect - withdrawal syndrome, or rebound syndrome. This is expressed by the fact that after stopping the medication there is an increase in acidity and an exacerbation of the disease. Therefore, it is not recommended to suddenly quit these medications.

Drugs belonging to the group of H2-histamine blockers

There are few drugs related to H2-histamine receptor blockers, this is explained by their low demand in recent years. These include:

• "Cimetidine";
• "Ranitidi";
• Famotidine.

These are well-known representatives of the first, second and third generation of H2 blockers. More modern drugs of the 4th and 5th generations are undergoing clinical trials and are therefore little known.

Medicines are improved and improved over time. And if initially “Cimetidine” was used in a daily dose of 200–800 mg, then modern “Famotidine” is produced with a minimum dose of 10 mg.

Cimetidine (H2 blocker) versus Omeprazole (PPI)

These are the first representatives of two groups: H2-histamine receptor blockers and proton pump inhibitors, respectively. In what way is the first group inferior to the second?

1. The first disadvantage is rebound syndrome in Cimetidine and other H2 blockers.
2. Another disadvantage is the effect of H2 blockers on potency, significantly reducing it to the point of complete absence.
3. Long-term use of H2 blockers impairs liver and kidney function.
4. The need for two or three times daily application.
5. The dose-dependent effect of administration - the higher the dose of the drug, the higher the likelihood of complete inhibition of hydrochloric acid production.

It is difficult to call proton pump inhibitors ideal drugs. But which drugs have no downsides? The obvious negative aspects of PPI are as follows.

1. Over time, after long-term use, resistance develops to many drugs of this group - addiction, as a result of which in the future, with an exacerbation of the disease, it will be difficult to select a drug of this group.
2. Possibility of “night acid breakthrough”, where 70% of patients taking PPIs experienced a phenomenon of low acidity at night for one hour or more.

We can conclude that H2-histamine receptor blockers are currently inferior to proton pump inhibitors. Therefore, of the H2 blockers, only Famotidine remains relevant in Russia today. But PPIs also have their drawbacks, the main one being nighttime acid breakthrough in most patients. Therefore, for some, Famotidine is a more acceptable solution than taking a PPI.

When choosing medications, it is important to weigh the pros and cons. The benefits of PPIs seem obvious. But only H2 receptor blockers have one undeniable advantage - the ability to administer these substances by injection. Thus, it is difficult for seriously ill patients and patients with oncology, for example, of the esophagus, to swallow medications. Only intravenous and intramuscular administration saves such weakened patients from heartburn.

Side effects and contraindications of H2 blockers

• pregnant and breastfeeding women;
• children under 14 years of age;
• people with impaired liver and kidney function.

The most common side effects include:

• frequent headaches, dizziness and depression, tinnitus;
• allergic rashes, muscle pain of varying severity;
• from the reproductive system - gynecomastia (breast enlargement in men), impotence;
• dry mouth, nausea, vomiting, constipation and diarrhea;
• severe fatigue;
• inhibition of liver function and deterioration of kidney excretory function.

Individual selection of drugs

There is a need for individual selection of medications, this is due to the characteristics of the body.

In some patients with heartburn, acid is better reduced by H2-histamine blockers than by proton pump inhibitors. Nocturnal acid breakthrough, for example, from Omeprazole, is more difficult for people who work mainly at night. That is why drugs are prescribed individually and only after consulting a doctor.

H2 blockers may not be the most commonly prescribed group of drugs, but for allergic reactions to other medications, they are quite suitable for combating heartburn, and some modern developments may well compete with proton pump inhibitors. It's good to have plenty to choose from!