Cardiotonic drugs are drugs that increase the activity of the heart muscle, its contractility and are used in the treatment of heart failure. The group includes a significant number of drugs that have different active substances in the composition and a different mechanism of action. Cardiotonics are used to treat acute and chronic heart failure.
Cardiotonic drugs: classification
The overall effect of all drugs in the group is based on the ability to increase the strength of myocardial contractions, resulting in an increase in cardiac output and stroke volume. Cardiotonic agents reduce diastolic volume, pulmonary and systemic venous pressure, and ventricular filling pressure.
- Cardiac glycosides - Strofanthin, Korglikon, Digoxin.
- Adrenergic drugs – Isadrin, Dobutamine, Dopamine.
- Nonadrenergicsynthetic drugs - "Amrinon", "Milrinon".
The choice of drugs used is related to the severity of the patient's condition and the form of the course of the disease.
Cardiac glycosides
The group is represented by means of plant or synthetic origin. Preparations based on herbal substances obtained from foxglove, adonis, spring lily of the valley, oleander, strophanthus, etc.
The duration of the therapeutic effect, the effect of accumulation in the body and the neurotoxicity of drugs completely depend on their ability to form complexes with blood plasma proteins. The stronger this connection, the higher the efficiency of the glycoside. Cardiotonic agents of this group have an effect based on the following mechanisms:
- there is a shortening of systole with its simultaneous increase;
- heart muscle rest period lengthens;
- heart rate drops;
- increases the ability of the myocardial muscle to excite;
- with an overdose of drugs, ventricular arrhythmia develops.
Digoxin
The drug is synthesized from digitalis leaves. Refers to long-acting glycosides that do not give serious side effects. It is used for the complex treatment of chronic heart failure and tachysystolic arrhythmia.
Produced in the form of tablets and injection solution. The dose must be selected carefully for each patientindividually. In case of using other cardiac glycosides before Digoxin, the dosage is reduced.
Strophanthin
Is a short-acting cardiac glycoside used in cases of acute deficiency. "Strophanthin" does not tend to accumulate in the body. The drug enhances the contractile function of the myocardium and increase the minute volume of blood. In parallel, there is a reduction in the size of the heart muscle and a decrease in its need for oxygen.
Used intravenously, intramuscularly, in some cases - orally. Taking large amounts can lead to an overdose. Use with other drugs changes the effectiveness of the glycoside:
- with barbiturates the effect is reduced;
- with "Reserpine", sympathomimetics and antidepressants can cause the development of cardiac arrhythmias;
- reception with tetracyclines, "Levomycetin", "Amiodarone" and "Captopril" enhances the cardiotonic effect;
- magnesium sulfate contributes to the development of cardiac atrioventricular blockade.
Adrenergic drugs
Non-glycoside cardiotonic drugs with a short-term effect. The group is used in acute heart failure to support important body functions.
"Izadrin" is a stimulant of adrenoreceptors of blood vessels, bronchi and heart. The drug has a hypotensive effect, enhances the contractility of the heart muscle. It is used in cardiac surgery with a sharp decrease in contractility duringsurgical interventions, as well as in cardiogenic shock. Doctors' comments warn: misuse or overdose can cause ventricular fibrillation.
"Dobutamine" is a non-glycoside structure cardiotonic agent that has a stimulating effect on the heart muscle, and also normalizes coronary blood flow. The risk of developing arrhythmias when using this remedy is quite low, since Dobutamine has practically no effect on cardiac automatism.
Appointed with a quick need to strengthen the contractility of the myocardium. May cause side effects in some cases:
- nausea;
- headache;
- hypertension;
- increased heartbeat;
- chest pain.
"Dopamine" is a catecholamine that stimulates adrenoreceptors. The drug increases blood pressure, increases coronary blood flow. It is prescribed for acute myocardial insufficiency, shock. Use with caution in myocardial infarction, pregnancy, thyroid disease, arrhythmias.
Non-adrenergic synthetic cardiotonic drugs
These are cardiotonic agents used in cases of acute coronary insufficiency. The drugs act on the contractility of the heart muscle, strengthening it. They can provoke the development of arrhythmia and a decrease in blood pressure, disorders of the kidneys.
Cardiotonic drugs of this group cannot be used for heart defects,as well as cardiomyopathy, cardiac arrhythmia, aortic aneurysm, kidney failure, heart attack and during childbearing.
Means "Amrinon" is used exclusively in intensive care units, so that the patient is constantly under the control of special devices that signal his condition. In addition to enhancing heart contractions, the drug dilates blood vessels, increases blood flow during systole, and reduces pulmonary pressure.
Produced as a solution. For intravenous administration, it is diluted exclusively in physiological sodium chloride solution. Do not mix with other medicinal products. With the introduction, a sharp decrease in pressure, an increase in heart rate, arrhythmia, the appearance of headaches, and gastrointestinal disorders are possible.
"Milrinon" is more active than the first representative of the group, and according to reviews, it is better tolerated by patients. The use of the drug during pregnancy and the development of myocardial infarction is contraindicated. Refers to group A drugs. The need to use the drug is determined solely by the doctor.
Conclusion
Cardiotonic drugs have been proven effective several generations ago. Reviews indicate that drugs in this group help to cope with heart failure. However, taking such medications in the form of self-medication is strictly contraindicated due to the development of possible complications,side effects or overdose. The choice of the drug, as well as the dose of administration, is determined by the cardiologist in each clinical case individually.
