Indicate an oral anticoagulant for long-term prevention of thrombosis. Anticoagulants and their use in medicine

Anticoagulant drugs inhibit the activity of the blood coagulation system, preventing the formation of new blood clots or destroying existing ones. This group of drugs has become widespread in all branches of medicine.

Thanks to such drugs, mortality in surgical patients has significantly decreased. postoperative period.

Anticoagulants are substances or drugs that suppress the activity of the blood coagulation system and also prevent the formation of blood clots.

Drugs of this series used in all areas of medicine. However greatest distribution anticoagulants were obtained in cardiology and surgery. During any, even minor surgical interventions, the integrity of body tissues is compromised. In this case, the hemostatic system is activated, which is characterized by increased thrombus formation.

No correction of this state can lead to the development of acute disorders of the brain and coronary circulation, as well as thromboembolism of the branches of the pulmonary artery.

That is why it is extremely important to carry out adequate anticoagulant therapy in the postoperative period.

In cardiological practice, the use of anticoagulants becomes especially important in the post-infarction period, with arrhythmias, as well as heart failure.

Anticoagulants are prescribed for life to patients who have undergone stenting or coronary artery bypass grafting.

Natural anticoagulants

You can understand what anticoagulants are only by understanding the mechanism of action of these substances. IN human body There are both coagulation and anticoagulation systems. The first ones are responsible for formation of thrombotic masses when the integrity of vascular structures is violated. The latter prevent excessive activity of the blood coagulation system, and are also responsible for the timely breakdown of existing blood clots.

Natural anticoagulants are divided into primary and secondary. Primary factors constantly circulate in the vascular bed and prevent the uncontrolled formation of blood clots. They are also divided into several subcategories.

  1. Fibrin creation inhibitors– prevent the conversion of fibrinogen to fibrin.
  2. Antithromboplastic substances have an antiprotrobinase effect.
  3. Antithrombins– structures that bind thrombin.

A decrease in the activity of these substances causes the development of thrombosis, and is also one of the key factors in the appearance of DIC syndrome.

Primary blood anticoagulants are:

  • antithrombin III;
  • alpha2-antiplasmin;
  • heparin;
  • alpha macroglobulin;
  • apolyprotein A-11;
  • alpha2-antitrypsin;
  • placental anticoagulant - produced only when the placenta is formed;
  • C1-esterase inhibitor;
  • LAKI – Lipoprotein-associated coagulation inhibitor;
  • proteins S and C;
  • autoantibodies produced to active coagulation factors;
  • fibrin assembly inhibitor;
  • thrombomodulin;
  • glycoproteins.

Secondary factors are formed during the destruction of blood clots:

  • fibrin peptides;
  • antithrombin I;
  • metafactors – Va, Xia;
  • FDF are products of fibrin degradation, as well as fibrinogen;
  • degradation products of prothrombins Q, P, R.

Despite the diversity natural factors blood, the balance between the coagulation and anticoagulation systems is not always achieved. Insufficient activity natural anticoagulants and excessive activity of the blood coagulation system can lead to increased thrombus formation. In this case, there is a need to use anticoagulant drugs.

Anticoagulant drugs

Modern anticoagulants allow you to influence the blood coagulation system, reducing its activity.

This leads to a decrease in blood viscosity and the likelihood of blood clots.

The mechanism of action of anticoagulants depends on the class of drugs to which they belong.

For a better understanding, classifications have been created that indicate the points of action of specific groups of drugs.

Classification

Classification of anticoagulants begins with separation of drugs by mechanism of action. There are drugs that act directly on blood clotting factors - they are also called direct.

Indirect drugs include drugs that affect metabolic processes liver, reducing the synthesis of vitamin K. The latter is important factor conversion of prothrombin to thrombin (platelet cell of hemostasis).

There are main classes of anticoagulants direct action And indirect action:

  1. Heparins– Antithrombin III, Sulodexide, Enoxyparin.
  2. Vitamin K antagonists– Warfarin, Acenocoumarol, Phenindione.
  3. Thrombolytics– Streptokinase, Fibrinolysin, Tenecteplase, Alteplase, Urokinase, Protein C, Ancord.
  4. Direct factor Xa inhibitors- Darexaban, Rivaroxab, Apixaban, Betrixaban, Endoxaban.
  5. Antiplatelet agents– Clopidogrel, acetylsalicylic acid, Indobufen, Ticagrelor, Dipyridamod, Abciximab, Ticlopidine.
  6. Direct thrombin inhibitors– Bivalirudin, Lepirudin, Dabigatran, Ximelanatran, Desirudin, Melanatran, Argatroban.
  7. Other antithrombotics— Fondaparinux, Defibrotide, dermatan sulfate.

Many patients with a history of atrial fibrillation, ischemia or myocardial infarction, or transient ischemic attack of the brain prefer to carry with them a tablet anticoagulant that they can quickly drink.

Those people who have a high risk of developing heart disease vascular events, It's better to ask your doctor, what kind of new oral anticoagulants are these, and which one is best to always have with you. The medicine may vary (depending on the patient's health condition). Usually this is Dabigatran, Apixaban, eparin.

Direct acting drugs

In turn, direct-acting drugs are divided into the following subcategories:

  • heparins, as well as their derivatives;
  • low molecular weight heparins;
  • sodium hydrogen citrate;
  • danaparoid, as well as lepirudin;
  • hirudin.

Indirect acting drugs

List of anticoagulant drugs with indirect mechanism actions can also be divided into subcategories:

  • dicoumarins;
  • monocoumarins (derived from oxcoumarin);
  • indandiones.

Coumarin anticoagulants have been used in medicine since the 40s of the twentieth century. IN this moment they are not as widespread as other groups, however actively used in cardiology.

In particular, Warfarin is a key drug of therapy atrial fibrillation. It prevents the formation of blood clots in the right ear of the heart and reduces the risk of adverse cardiovascular complications.

Indadiones are less widespread in medical practice.

Indications for use

You can understand what anticoagulants are in medicine by knowing the indications for the use of these drugs. There is a list of situations in which the use of anticoagulants is mandatory.

  1. Postoperative period.
  2. Conditions after acute disorder cerebral circulation.
  3. Previous myocardial infarction.
  4. branches of the pulmonary artery.
  5. Atrial fibrillation.
  6. , and .
  7. Obliterating endarteritis.

Violations normal rhythm heart disease contributes to increased thrombus formation, and significantly increases the risk of strokes, heart attacks, and pulmonary embolism. Therefore, the cardiologist must prescribe a specific list of anticoagulant drugs for arrhythmias, the use of which reduces the risk of developing these complications.

The choice of group and drug depends on the health status of the individual patient, his pathology and the state of the blood coagulation system. For this purpose, there is a coagulogram, which displays the functional activity of the blood system before, during and after the use of drugs.

Any doctor can prescribe anticoagulant drugs if he sees a risk of thrombotic complications. Above are the most common cases. However, these drugs can also be prescribed in other branches of medicine.

Contraindications

Any anticoagulant agent should be prescribed with caution to women during pregnancy. These drugs can only be used under the control of a coagulogram and in situations where there is a risk undesirable consequences for mother and child is higher than from possible side effects.

There are other contraindications to anticoagulants, which include:

Prescribe anticoagulants with caution and for infectious pathologies.

Natural remedies

Some products also have anticoagulant activity.

  1. Large volumes of liquid - water, compote, tea.
  2. Cucumbers.
  3. Watermelon.
  4. Flaxseed oil and low-fat varieties fish.
  5. Oatmeal porridge.
  6. Cranberry drinks made from other dark berries.
  7. Iodine-containing products – seaweed.
  8. Grape drinks.

Unfortunately, the use of these products does not allow the hemostasis system to be fully maintained at the proper level.

However, people who take anticoagulant drugs need to remember about such properties - Excess consumption can cause internal and external bleeding..

Conclusion

There are clear indications and contraindications for the use of antithrombotic drugs. They should be taken only as prescribed by the attending physician under the strict control of a coagulogram.

Despite existing contraindications and possible side effects, you should not be afraid of taking these medications. Their use can prevent the development of severe complications and even save a person’s life.

IN drug therapy Anticoagulants are used to prevent blood clotting. For diseases directly or indirectly related to thrombus formation, they can be considered vital. The list of anticoagulant drugs includes direct and indirect drugs.

Prescribed for treatment:

  • Acute venous and arterial thrombosis.
  • Pathologies associated with release from tissues large quantity thromboplastic substances.
  • After previous operations to prevent the formation of blood clots.
  • As preventive measures in the presence of heart disease.

What drugs are classified as anticoagulants? These medications have blood thinning properties and are also called anticoagulants. They are divided into two groups: direct and indirect action.

List of direct anticoagulant drugs

This group includes antithrombolic medications that reduce the clotting factor (thrombin) in the blood.

1. Heparins for local application(externally).

These drugs related to anticoagulants are prescribed for internal inflammation veins with the formation of a blood clot in their cavity.

Stop inflammatory process. Reduce platelet aggregate formation and thrombin activity. Relieves swelling. Activate tissue respiration. They help dissolve blood clots and gradually restore the lumen of the veins. Reduces painful sensations.

The list includes direct anticoagulant drugs Russian production:

1. Heparin ointment 25 g - 50 rubles.
2. Heparin-Akrikhin 1000 gel 30 g - 224 rub.
3. Trombless gel 30 g - 249 rub.
4. Venolife 40 grams - 330 rub.
5. Laventum 50 g - 290 rubles.

For subcutaneous and intravenous administration

Anticoagulant drugsare used in the treatment of deep vein thrombosis, pulmonary artery thrombolism, and angina pectoris. They are thrombin blockers. Prevents the formation of non-globular fibrin protein and platelet aggregation.

As therapeutic therapy the doctor prescribes:

1. Clexane (France). Basic active ingredient enoxaparin sodium prevents blockage by a blood clot blood vessels and the formation of blood clots.

  • Syringes 0.2 ml 10 pcs. - 1700 rubles.

2. Fraxiparine (France). Active substance nadroparin calcium has high Xa-factor activity. Used to thin the blood when there is a risk of thrombosis.

  • Syringes 2850 ME 0.3 ml 10 pcs. - 2150 rub.

3. Fragmin (USA). Prescribed to patients undergoing hemodialysis or hemofiltration. Effective drug blood anticoagulant. Active substance solution alteparin sodium has an anticoagulant effect. Reduces speed chemical reactions coagulation factor and thrombin.

  • Solution 2500 anti-Xa ME/0.2 ml 10 pcs. - 2100 rubles.

Indirect anticoagulant drugs

The active substances of medications included in this group disrupt the synthesis of prothrombin in the liver and slow down the blood clotting process. Prothrombin is a precursor to the enzyme thrombin. Refers to complex blood plasma proteins. Participates in blood clotting with the participation of vitamin K.

List of anticoagulant drugs in tablets

1. Warfarin (Russia). The most popular drug from the list of indirect anticoagulants for the treatment of thrombosis venous system. Reduces the likelihood of thromboembolic complications.

If you follow a diet, constantly monitor your blood for INR and dosage, therapy leads to positive results. Affordable price another significant advantage of the medication.

  • Tab. 2.5 mg 50 pcs. - 86 rubles.

2. Fenilin (Russia). Another indirect anticoagulant drug effective remedy in tablet form. Active substance phenindione has anticoagulant properties.

Prescribed for blockage of the walls of veins and blood vessels lower limbs and brain. It is used as a preventive measure after surgical interventions.

  • Packaging tab. 20 mg 30 pcs. - 120 rub.

3. Sinkumar (Russia). The drug is included in the list of coumarin anticoagulant drugs. Prevents the synthesis of vitamin K in its active form, as a result of which the coagulation process (formation of blood clots) is disrupted. Suppresses the synthesis of blood clotting factors.

  • Packaging tab. 2 mg 50 pcs. - 470 rub.

New generation anticoagulants

A feature of the drugs is the ability not to constantly monitor the blood clotting index (INR). Judging by this property, the new drugs are superior to Warfarin in ease of use. However, high price drugs limits their availability, which is a significant drawback.

The list of new generation anticoagulant drugs includes:

1. Xarelto (Germany). Active component medicine is rivaroxaban. Clinical researches proved high efficiency this tool. Easy to use. Does not tie patients to constant testing.

  • Cost of 15 mg tablet 28 pcs. - 2700 rub.

2. Eliquis (USA). Main active ingredient apixaban restores vein patency. Used for the prevention of cardioembolic stroke. Does not require systematic monitoring of hemostasis.

  • Price of tablets 5 mg 60 pieces - 2400 rub.

3. Pradaxa (Austria). The main component of the medicine dabigatran etexilate. Prescribed for venous and systemic thromboembolism, including lesions pulmonary artery after severe injuries and complex operations.

Well tolerated. During drug therapy, practitioners note low risk bleeding.

  • Capsules 110 mg 30 pcs. - 1750 rubles.

Pathological tachycardia requires medication or surgical treatment

Complications caused by vascular thrombosis - main reason death from cardiovascular diseases. Therefore, modern cardiology places great emphasis on great importance preventing the development of thrombosis and embolism (blockage) of blood vessels. Blood clotting in in simple form can be represented as the interaction of two systems: platelets (cells responsible for the formation of a blood clot) and proteins dissolved in the blood plasma - coagulation factors, under the influence of which fibrin is formed. The resulting thrombus consists of a conglomerate of platelets entangled in fibrin threads.

To prevent the formation of blood clots, two groups of drugs are used: antiplatelet agents and anticoagulants. Antiplatelet agents prevent the formation of platelet clots. Anticoagulants block enzymatic reactions leading to the formation of fibrin.

In our article we will look at the main groups of anticoagulants, indications and contraindications for their use, and side effects.

Depending on the point of application, direct and indirect anticoagulants are distinguished. Direct anticoagulants inhibit thrombin synthesis and inhibit the formation of fibrin from fibrinogen in the blood. Indirect anticoagulants inhibit the formation of blood clotting factors in the liver.

Direct coagulants: heparin and its derivatives, direct thrombin inhibitors, as well as selective inhibitors factor Xa (one of the blood clotting factors). Indirect anticoagulants include vitamin K antagonists.



Vitamin K antagonists

Indirect anticoagulants are the basis for the prevention of thrombotic complications. Their tablet forms can be taken long time V outpatient setting. The use of indirect anticoagulants has been proven to reduce the incidence of thromboembolic complications (stroke) in the presence of an artificial heart valve.

Phenylin is not currently used due to high risk unwanted effects. Sinkumar has a long period action and accumulates in the body, so it is used infrequently due to the difficulties of monitoring therapy. The most common vitamin K antagonist drug is warfarin.

Warfarin differs from other indirect anticoagulants in its early effect (10–12 hours after administration) and the rapid cessation of unwanted effects when the dose is reduced or the drug is discontinued.

The mechanism of action is associated with the antagonism of this drug and vitamin K. Vitamin K is involved in the synthesis of some blood clotting factors. Under the influence of warfarin, this process is disrupted.

Warfarin is prescribed to prevent the formation and growth of venous blood clots. It is used for long-term therapy with atrial fibrillation and in the presence of an intracardiac thrombus. In these conditions, the risk of heart attacks and strokes associated with blockage of blood vessels by detached particles of blood clots is significantly increased. The use of warfarin helps prevent these serious complications. This drug is often used after a myocardial infarction to prevent a recurrent coronary accident.

After heart valve replacement, warfarin is required for at least several years after surgery. This is the only anticoagulant used to prevent the formation of blood clots in artificial valves hearts. You need to take this medicine regularly for some thrombophilias, in particular antiphospholipid syndrome.

After 50 years, blood vessels become less elastic and there is a risk of blood clots. To avoid the risk of excessive blood clots, doctors prescribe anticoagulants. Anticoagulants are also prescribed for treatment varicose veins veins

Anticoagulants are a group of drugs that affect the formation of blood clots. They prevent the process of platelet blood clotting, affecting the main stages functional activity blood clots, thereby blocking platelet coagulation.

In order to reduce the number of tragic disease outcomes of cardio-vascular system, doctors prescribe anticoagulants.

The main mechanism of action of anticoagulants is to prevent the formation and expansion of blood clots that can block an artery vessel, thereby reducing the risk of stroke and myocardial infarction.

Classification of anticoagulants

Based on the mechanism of action on the body, the speed of achieving positive effect and duration of action, anticoagulants are divided into direct and indirect. The first group includes drugs that provide direct impact on blood clotting and stop its speed.

Indirect anticoagulants do not have a direct effect; they are synthesized in the liver, thereby slowing down the main blood clotting factors. They are produced in the form of tablets, ointments, and injection solutions.

Direct anticoagulants

They are fast-acting drugs, having a direct effect on blood clotting. They take part in the process of formation of blood clots and, stopping the development of already formed ones, stop the formation of fibrin threads.

Direct-acting anticoagulants have several groups of drugs:

  1. Sodium hydrogen citrate.
  2. Heparin.
  3. Low molecular weight heparin.
  4. Hirudin.
  5. Danaparoid, lepirudin.

Heparin is widely known as a direct anticoagulant. Most often it is used in the form of an ointment or administered intravenously or intramuscularly. The main medications of the heparin series are: reviparin sodium, adreparin, enoxaparin, nadroparin calcium, parnaparin sodium, tinzaparin sodium.

Heparin is a direct anticoagulant for intravenous or subcutaneous administration

In most cases, penetrating into skin covering, are not very effective. Typically, they are prescribed for the treatment of varicose veins of the legs and bruises. The more popular heparin-based ointments are:

  • Trombless gel;
  • Troxevasin.

Heparin-based medications are always selected individually, both for intravenous and subcutaneous administration.

Analogs direct anticoagulant Heparin (Lioton gel, Gepatrombin, Trombless, Venolife)

It is worth remembering that subcutaneous and intravenous anticoagulants do not replace each other and have completely different effects.

Usually provide therapeutic effect heparins are started a couple of hours after use, continuing to maintain the effect on the body throughout the day. By reducing the activity of plasma and tissue factors, heparins block thrombin and serve as a barrier to the formation of fibrin threads and prevent platelet aggregation.

Indirect anticoagulants

By reducing the production of prothrombin in the liver, blocking the production of vitamin K, slowing down the formation of proteins S and C, they thereby affect blood clotting.

The group of indirect anticoagulants includes:

  1. Indan-1,3-dione derivatives, which are always produced in tablet form. Effect of use medicinal product occurs within 8 hours and continues throughout the day.
  2. Coumarin - the main active ingredient of the drug is contained in the form of sugars in a number of plants: sweet clover, bison. The drug of this group was first invented in the 20th century and was derived from clover leaves. The group of coumarin drugs includes (warfarin, neodicoumarin, acenocoumarol (Sincumar)).

New generation oral anticoagulants

To date modern group anticoagulants have become indispensable drugs in the treatment of diseases such as arrhythmia, ischemia, thrombosis, heart attacks, etc. However, like any medical supplies, they have a huge range side effects. The pharmacological industry does not stand still and developments to find anticoagulants that do not have side effect on other organs, continues to this day.

In addition, they are not approved for use for all types of diseases. Currently, we are actively developing a group of anticoagulants that in the future will not be contraindicated for use by children, pregnant women, and a number of patients for whom treatment with current anticoagulants is prohibited.

Advantages and disadvantages

The positive qualities of anticoagulants are:

  • Significantly reduce the risk of bleeding;
  • Coming time medicinal action the duration of the drug is reduced to 2 hours and they are easily eliminated from the body;
  • The range of patients who can use anticoagulants has expanded, thanks to a reduced risk of side effects of the drug (liver and gastrointestinal diseases, lactase intolerance, etc.);
  • The impact of other medications and food on the effect of anticoagulants.

However, new generation anticoagulants also have their disadvantages:

  1. The medications are taken regularly, unlike older generation anticoagulants, the use of which could be skipped.
  2. Possible risk of bleeding in gastrointestinal tract.
  3. During use, many patients experienced intolerance to the new generation of anticoagulants, in the absence of any side effects of the old modifications.

The effectiveness of the drugs has been proven; they reduce the risk of stroke or heart attack due to arrhythmia of any type.

3 stages of blood clotting in the human body and the participation of platelets in it

When prescribing oral anticoagulants, remember that there are many side effects and contraindications. Before use, be sure to read the instructions for the drug and consult with your doctor. Do not forget that when taking anticoagulants, you must adhere to a special diet, be sure to undergo monthly examinations and check certain blood parameters. In cases of suspicion of internal bleeding, you must immediately apply for medical care. In cases where taking anticoagulants causes bleeding, the medication must be replaced with another.

Antiplatelet agents and anticoagulants: the difference between drugs

Antiplatelet agents thin the blood and prevent the formation of blood clots in the vessels. Their mechanism of action on the body differs from anticoagulants. Widely popular antiplatelet agents are:

  • Aspirin is the most popular all over the world, however, allergy sufferers often have a reaction to this substance;
  • Dipyridamole – dilates blood vessels;
  • Ticlopidine - used for coronary heart disease, heart attack, and also for the prevention of thrombosis;
  • Tirofiban – prevents platelet aggregation;
  • Eptifibatide – has a blocking effect on platelet aggregation.

By stopping the clumping of platelets, they reduce the level of blood clotting. In addition, they are antispasmodics and vasodilators.

Video: Anticoagulants and their effect on the blood system

Anticoagulants are drugs that prevent the formation of blood clots in blood vessels. This group includes 2 subgroups of drugs: direct and indirect anticoagulants. We already talked about it earlier. In the same article we briefly described the principle normal functioning blood coagulation systems. In order to better understand the mechanisms of action of indirect anticoagulants, we strongly recommend that the reader familiarize himself with the information available there, with what happens normally - knowing this, it will be easier for you to navigate which phases of coagulation are affected by the drugs described below and what they involve the effects they have.

Mechanism of action of indirect anticoagulants

Drugs in this group are effective only when administered directly into the body. When mixed with blood in the laboratory, they do not affect clotting. They do not act directly on the blood clot, but influence the coagulation system through the liver, causing a number of biochemical reactions, as a result of which a condition similar to hypovitaminosis K develops. As a result, activity decreases plasma factors blood clotting, thrombin is formed more slowly, which means a blood clot forms more slowly.

Pharmacokinetics and pharmacodynamics of indirect anticoagulants

These drugs are absorbed well and fairly quickly in the gastrointestinal tract. With the blood flow they reach various organs, mainly the liver, where they carry out their effects.
Rate of onset, duration of effect and half-life of different drugs of this class vary.

They are excreted from the body mainly in urine. Some members of the class turn their urine pink.

Medicines in this group exert their anticoagulant effect by disrupting the synthesis of blood clotting factors, thereby gradually reducing the rate of this process. In addition to the anticoagulant effect, these drugs reduce the tone of the muscles of the bronchi and intestines, increase the permeability of the vascular wall, reduce the lipid content in the blood, inhibit the reaction of antigen-antibody interaction, and stimulate the excretion of uric acid from the body.

Indications and contraindications for use

Indirect anticoagulants are used for the prevention and treatment of thrombosis and thromboembolism in the following conditions:

  • after surgical interventions on the heart and blood vessels;
  • at ;
  • PE – for pulmonary embolism;
  • at ;
  • with aneurysm of the left ventricle;
  • at ;
  • with thromboangiitis obliterans;
  • with obliterating endarteritis.

Contraindications to the use of drugs in this group are:

  • hemorrhagic diathesis;
  • hemorrhagic stroke;
  • other diseases accompanied by;
  • increased vascular permeability;
  • severe renal and liver dysfunction;
  • pericarditis;
  • myocardial infarction accompanied by high blood pressure;
  • pregnancy period;
  • These drugs should not be taken during the period (2 days before the planned start, their medication is discontinued) and in the early postpartum period;
  • Prescribe with caution to elderly and senile patients.

Features of the action and use of indirect anticoagulants

Unlike direct-acting anticoagulants, the effect of drugs in this group does not appear immediately, but as it accumulates active substance in organs and tissues, that is, slowly. On the contrary, they act for a longer period of time. The speed, strength of action and degree of cumulation (accumulation) vary among different drugs of this class.

They are used exclusively internally or orally. They cannot be used intramuscularly, intravenously or subcutaneously.

Therapy with indirect-acting anticoagulants should not be stopped immediately, but gradually - slowly reducing the dose and increasing the time between doses of the drug (up to 1 time per day or even every other day). Abrupt withdrawal of the drug may lead to a sudden compensatory increase in the level of prothrombin in the blood, which will cause thrombosis.

If an overdose of drugs from this group is used or if they are used for too long, they can become a cause, and it will be associated not only with a decrease in blood clotting ability, but also with an increase in the permeability of the capillary wall. Less often in this situation, bleeding from the oral cavity and nasopharynx develops, gastrointestinal bleeding, hemorrhages in the muscles and joint cavity, and also micro- or macrohematuria appears.

To avoid the development of the complications described above, it is necessary to carefully monitor the patient’s condition and laboratory indicators of blood clotting during treatment with indirect anticoagulants. Once every 2-3 days, and in some cases more often, the prothrombin time should be determined and the urine examined for the presence of red blood cells (hematuria, that is, the presence of blood in the urine, is one of the first signs of a drug overdose). For more complete control, in addition to the prothrombin content in the blood, other indicators should be determined: heparin tolerance, recalcification time, prothrombin index, plasma fibrinogen, prothrombin content using a 2-step method.

Should not be administered concomitantly with these medicines drugs from the salicylate group (in particular, acetylsalicylic acid), since they help increase the concentration of free anticoagulant in the blood.

There are actually few drugs in the group of indirect-acting anticoagulants. These are neodicoumarin, acenocoumarol, warfarin and phenindione.
Let's look at each of them in more detail.

Neodicoumarin (Pelentan, Trombarin, Dicumaril)

When taken orally, it is absorbed relatively quickly, the half-life is 2.5 hours, and is excreted in the urine not in its original form, but in the form of metabolic products.

The expected effect of the drug begins to appear 2-3 hours after taking it, reaches a maximum in the period of 12-30 hours and continues for another two days after discontinuation of the drug.

Used independently or in addition to heparin therapy.

Release form: tablets.

Dosage according to the scheme, maximum daily dose– 0.9 g. The dose is selected depending on the prothrombin time indicators.

Acenocoumarol (Sincumar)

Well absorbed when taken orally. It has a cumulative effect (that is, it acts when a sufficient amount of it accumulates in the tissues). The maximum effect is observed 24-48 hours after the start of treatment with this drug. After canceling it normal level prothrombin is determined after 48-96 hours.

Release form: tablets.

Taken orally. On the first day, the recommended dose is 8-16 mg; subsequently, the dosage of the drug depends on prothrombin values. As a rule, the maintenance dose is 1-6 mg per day.
Possible increased sensitivity the patient's body to this drug. If allergic reactions it needs to be cancelled.

Fenindione (Fenilin)

A decrease in blood clotting ability is observed 8-10 hours after taking the drug, reaching a maximum after about a day. Has a pronounced cumulative effect.

Release form: tablets.

The initial dose is 0.03-0.05 g three times a day in the first 2 days. Further dosages of the drug are selected individually depending on blood parameters: the prothrombin index should not be less than 40-50%. The maximum single dose is 0.05 g, daily dose is 200 mg.

During treatment with phenyline, skin staining and urine color change may occur. If these symptoms occur, phenindione should be replaced with another anticoagulant.


Warfarin (Warfarin)

Absorbed completely in the gastrointestinal tract. The half-life is 40 hours. The anticoagulant effect begins 3-5 days after the start of treatment and continues for 3-5 days after discontinuation of the drug.

Available in tablets.
Treatment is started with 10 mg once a day, after 2 days the dosage is reduced by 1.5-2 times - to 5-7.5 mg per day. Therapy is carried out under the control of the blood indicator INR (international normalized ratio). In certain clinical situations, for example, when preparing for surgical treatment, the recommended dosages of the drug vary and are determined individually.