Violation of the rheological properties of blood with an increase in the activity of the coagulation (coagulation) system leads to the formation of blood clots and blockage of blood vessels. Myocardial infarction, ischemic stroke, gangrene of the lower extremities and internal structures are the consequences of such an imbalance in the body. In order to prevent massive thrombosis in practice, anticoagulants are used - drugs that prevent the formation of blood clots. One of the oldest, available and used agents is heparin, obtained from the lung tissue of cattle.
Instructions for use
Heparin is a high molecular weight compound with a mass of 16,000 Daltons, which is produced by mast cells (tissue basophils) of the blood together with histamine and other biologically active substances.
The mechanism of action of heparin is associated with blocking blood coagulation factors, activation of the anticoagulant system (due to interaction with antithrombin III, the function of which increases 700 times). Thus, the time of plasma hemostasis is lengthened, the formation of blood clots is reduced.
The properties of the drug depend on the fraction:
- low - prevent the formation of blood clots;
- medium - cause hypocoagulation, lengthen prothrombin time;
- high - have antiplatelet properties, reduce the "adhesion" of platelets.
In addition, Heparin has other pharmacological actions, which leads to widespread use in practice:
- anti-inflammatory and immunosuppressive - suppressing antibody-antigen reactions, activation of the complement system;
- antiplatelet - "thinning" of the blood;
- hypoglycemic - by increasing the activity of insulin, reducing blood sugar levels;
- antiallergic: heparin acts as an antagonist of histamine - the main mediator of allergy;
- antiatherosclerotic by reducing the concentration of cholesterol and beta-lipoproteins in the blood plasma;
- enhances the secretion of thyroid hormones;
- diuretic (weak diuretic).
The wide spectrum of action of the drug requires careful use due to severe complications.
The drug does not penetrate the fetoplacental barrier, which makes Heparin the drug of choice for the treatment of thrombosis in pregnant women.
Indications for use
Instructions for the use of Heparin assumes the use of the drug in the following cases:
| Injection form (subcutaneous or intravenous) | Topical (ointment, spray, or gel) |
|---|---|
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In addition, medication is used to flush catheters that are placed for long-term venous access.
In medical practice, unfractionated (whole) heparin is most often used. However, there are modern drugs - low molecular weight analogues, which are often used to prevent thrombus formation in patients with acute or chronic renal failure on hemodialysis (Enoxyparin, Fraxiparin).
Composition and dosage forms
The drug is available for parenteral (vial with solution for injection) and external use.
The composition of the product, depending on the form, is presented in the table.
| Injection form (subcutaneous or intravenous) | Active substance | Supporting components |
|---|---|---|
| Solution for injection (10 vials of 5 ml per package) | Heparin Sodium at a concentration of 5000 IU / ml |
|
| Gel for external use (tube of 30 or 50 grams) | Sodium heparin 1000U / g |
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| Heparin ointment (tubes of 50 and 100 grams) |
|
|
There is no oral form for internal administration (tablets, capsules, syrup) with heparin, since the active molecule is destroyed by enzymes in the digestive tract before it can enter the bloodstream.
Dosage and method of administration
The selection of the effective dose of the drug, the route of administration and the duration of the course depends on the pathology, age and weight of the person. Most often in inpatient treatment, subcutaneous injections of Heparin are prescribed, which are used in a dosage:
- with myocardial infarction - 7500 IU 3 times a day or 10000-12500 IU 2 times a day;
- preoperative prevention of thromboembolic complications, 2500-4000 IU 2 hours before the intervention, and every 6-8 hours after.
The technique of subcutaneous injection (most often in the abdomen) involves the use of a special syringe ("insulin") for accurate dosage with the introduction of the needle at an angle of 30 °.
Intravenous fluids are used to provide emergency medical care for:
- venous and arterial thromboembolism (pulmonary, mesenteric, cerebral, renal vessels) according to the algorithm up to 10,000 IU in a stream, then through a dispenser-perfuser 25-40 thousand IU / day. For children, the required dose is calculated by weight: the first dose is 50 U / kg, then - 20 U / kg / hour.
- DIC syndrome (hypercoagulable phase) - enter 2500-4000 U / day.
Parenteral manipulations are performed by a doctor or nursing staff.
Local use of the drug (gel, ointment) is prescribed for patients with pathologies of superficial vessels (varicose veins, thrombophlebitis, thrombosis of hemorrhoidal veins). Application features:
- the product is applied in a thin layer to the skin 2-3 times a day;
- with hemorrhoids - injected with a gauze swab or under a bandage (with the external location of the nodes);
- the duration of local therapy is determined by the attending physician, usually up to 3 weeks;
- can not be applied to damaged skin (wound), mucous membranes and in the area of purulent inflammation.
To prevent overdose and the effectiveness of the selected amount, coagulogram control is used, a specific indicator is APTT (activated partial thromboplastin time).
Contraindications
The pronounced anticoagulant effect of the drug and the effect on other organs and systems forms a list of conditions in which heparin is contraindicated:
hemorrhagic diathesis: thrombocytopathy, thrombocytopenia, vasculitis (vascular pathology), hemophilia;- hypersensitivity (allergic reaction) to the components of the drug;
- peptic ulcer of the stomach and duodenum;
- malignant neoplasms;
- hemorrhagic stroke or injury to the central nervous system;
- endocrine pathologies of the thyroid gland (with caution in patients with diabetes mellitus);
- malignant arterial hypertension;
- infective endocarditis (due to an increased risk of a blood clot separating from the valve);
- adenoma of the prostate gland (contraindication for rectal use).
hemorrhagic diathesis: thrombocytopathy, thrombocytopenia, vasculitis (vascular pathology), hemophilia;It is forbidden to inject heparin in the early postoperative period after neurosurgical, abdominal and ophthalmological interventions, in the case of using epidural anesthesia.
The tool is not used if the rules for the manufacture or storage of the solution are violated.
Side effects
Heparin belongs to the group of mucopolysaccharides of animal origin with a wide range of pharmacological effects, therefore there are a number of side effects of the drug:
- allergic reactions: redness or rash in the area of application of the drug. With parenteral administration - lacrimation, fever, bronchospasm;
- dizziness;
- decreased appetite, nausea;
- increased bleeding - petechiae on the skin;
- gastrointestinal, renal, nosebleeds;
- transient hair loss (alopecia), osteoporosis, arterial hypotension (due to a decrease in the synthesis of aldosterone in the adrenal glands) - with prolonged use;
- increased activity of liver enzymes (rare).
The risk of bleeding increases with the simultaneous use of Heparin with indirect anticoagulants (Warfarin, Sinkumar), non-steroidal anti-inflammatory drugs (Aspirin).
The drug is not recommended for use with alcohol, high doses of antibiotics due to a significant increase in the activity of hepatic transaminases.
Overdose symptom and their treatment
The use of Heparin without following the recipe, especially when administered intravenously, is often accompanied by signs of an overdose in the form of bleeding from the gastrointestinal tract, urinary system, genitals, and sometimes cutaneous hemorrhagic rash.
In addition, complications are possible with cutaneous use over a large area (for example, in children - from feet to knees).
In case of intoxication, heparinized plasma is not prone to self-destruction of the process, therefore, specific antidote therapy is required - a 1% solution of protamine sulfate.
Dose calculation: 1 mg of antivenom binds 100 U of heparin. 50% of the funds must be administered in the first 90 minutes after the onset of symptoms of an overdose, the rest within 3 hours.
Additionally, pathogenetic and replacement therapy is used, if necessary, plasma transfusion.
Analogues and substitutes of the drug
The modern pharmaceutical market offers a number of drugs - analogs of Heparin for local and parenteral use:
- gels: Trombless, Lyoton 1000, Trombogel 1000;
- Viatromb gel spray;
- ointment: Thrombophobe;
- injection solution: Heparin Sodium, Heparin Lechiva.
In cardiological practice, heparin substitutes are often used - indirect anticoagulants, which help to fight increased thrombus formation with prolonged use. For the convenience of the patient, the funds are available in the form of tablets - Sinkumar, Warfarin, Fenilin, Neodikumarin.
Efficiency control for preparations of this cereal is an INR (International Normalized Ratio) indicator, which must be strictly carried out according to a special scheme
Conclusions
Heparin is a strong anticoagulant agent that is most often used in a hospital setting due to its wide range of effects and a high risk of overdose. Correctly selected concentration of the drug is used for increased formation of blood clots, myocardial infarction, stroke and other thromboembolic pathologies. The selection of the dose, method and frequency of administration is regulated by the doctor depending on the sensitivity of the patient and the presence of risk factors (old age, alcoholism, the use of other drugs).
