Digoxin

Digoxin is a therapeutic group of cardiac glycosides.

[1],

Indications Digoxin

It is used to correct heart rhythm disorders ( arrhythmias ) that have a supraventricular form (paroxysmal tachyarrhythmia, atrial fibrillation, and regular tachyarrhythmia of the atrial type).

The drug is included in the structure of therapeutic schemes for CHF of the 3rd and 4th subclasses, and in addition it is used in the case of CHF of the 2nd subclass, when diagnosing severe clinical symptoms.

[2]

Release form

The release of the drug is in the form of injectable liquid or tablets.

[3], [4]

Pharmacodynamics

The drug is of plant origin, the component digoxin is extracted from Digitális lanáta.

The drug has a powerful cardiotonic effect (a positive inotropic effect and an increase in the contractile activity of the heart muscle by increasing calcium ions inside the cardiomyocytes), which makes it possible to increase minute values and blood shock indicators. Reduces the need for oxygen saturation of myocardial cells.

At the same time, Digoxin has a negative chronotropic and dromotropic effects - reduces the frequency of the processes of generation of electrical impulses in the sinus node, and in addition, the speed of movement of the pulse through the AV-conducting cardiac system. In addition, it indirectly affects the end of the aortic arch and stimulates the activity of the vagus nerve, resulting in inhibited activity of the sinoatrial node.

These mechanisms can reduce the level of heart rate in the case of supraventricular tachyarrhythmias.

With the development of HF in severe form, as well as symptoms of stagnation in the small and large circles of blood flow, the drug has an indirect vasodilator effect, which develops by reducing systemic vascular resistance (inside the peripheral bed) and reducing the severity of dyspnea and peripheral puffiness.

[5], [6], [7], [8], [9], [10], [11], [12],

Pharmacokinetics

Orally consumed substance is absorbed inside the gastrointestinal tract by 70%, reaching Cmax after 2-6 hours. When used with food, there is a slight increase in the absorption period. Exceptions are products containing a large amount of plant fiber - in this case, part of the active element is adsorbed by its dietary fiber, after which it is no longer available.

Able to accumulate inside tissues with fluids (also inside the myocardium), which is used in the selection of the mode of use: the effect of the drug is calculated not by the values of plasma Cmax, but by equilibrium pharmacokinetic parameters.

50-70% of the drug excreted through the kidneys; in severe stage of renal disease, digoxin may accumulate inside the body. Half-life is 2 days.

[13], [14], [15], [16], [17]

Dosing and administration

To include Digoxin in therapeutic regimens is necessary only at the hospital. The drug interval of the drug (between therapeutic and toxic dose) is very short, which makes it necessary to strictly follow all indications regarding the use of drugs.

In the first phase of therapy (the stage of digitalization of the patient's body with medicine), the drug is used in a portion called saturating: the patient consumes 2-4 tablets (corresponding to 0.5-1 mg), and then switches to using the 1st tablet with a 6-hour interval. Reception according to this scheme is continued until the medical result is obtained, and the stable blood level of digoxin will be maintained for 7 days.

In the second phase of treatment, it is necessary to regularly use the maintenance dosage of the medication, often 0.5-1 to a tablet per day. It is forbidden to skip the use of drugs, as well as use a double portion for taking, if the application was missed. In this case, poisoning may develop, which can lead to death.

In cardiology, as well as cardio-resuscitation, Digoxin is also used for intravenous administration - to stop the supraventricular paroxysmal tachyarrhythmias.

[25], [26], [27]

Use Digoxin during pregnancy

The effect of the drug on the fetus has not been investigated during clinical tests, although it is known that its active element can pass through the hemato-placental barrier. Use of digoxin during pregnancy is allowed only with strict indications.

With the introduction of drugs during lactation, you need to regularly monitor heart rate indicators in an infant.

Contraindications

Main contraindications:

• symptoms of glycoside poisoning;
• the presence of strong sensitivity to digoxin;
• WPW syndrome;
• AV-blockade, with 2nd degree or complete AV-blockade;
• bradycardia;
• individual signs of coronary artery disease (unstable angina);
• exacerbation of myocardial infarction;
• isolated stenosis of the mitral valve;
• CH, having a diastolic form (cardiac tamponade, constrictive pericarditis, amyloid cardiopathy or cardiomyopathy);
• obesity;
• expansion of the heart departments in a pronounced form;
• failure of the kidneys or liver parenchyma;
• myocardial inflammation;
• hypertrophy in the area of the septum between the ventricles;
• subaortic stenosis;
• tachyarrhythmias of the ventricles.

[18], [19], [20], [21], [22]

Side effects Digoxin

First of all, you should respond to the appearance of negative symptoms associated with the work of the CAS, because they can be the first manifestations of emerging glycoside poisoning.

Among the manifestations is inhibition of AV conduction, as a result of which the heart rate slows down (development of bradycardia), and in addition the occurrence of heterotropic areas of myocardial excitation, resulting in ventricular extrasystole and ventricular fibrillation.

Extracardiac negative symptoms do not threaten the patient's life, which distinguishes them from intracardiac signs. Among these are disorders in the digestive system (vomiting, pain in the abdominal area, nausea and diarrhea) or NA (psychosis or depression, headaches and a disorder of the visual analyzer, manifested by the "front sights" in the eyes, etc.).

There may be a disorder in the morphological picture of hematopoietic activity in the form of thrombocytopenia, due to which petechiae appear on the epidermis.

In addition, allergy symptoms can occur - itching, rashes and erythema on the epidermis.

[23], [24],

Overdose

Signs of overdose (glycoside poisoning): slowing heart rate and the development of sinus bradycardia. On the ECG, there are manifestations of a slowdown in AV conduction, which can even reach the full AV blockade. Ventricular extrasystoles develop under the influence of heterotropic sources of rhythm; ventricular fibrillation may occur.

Of the extracardiac manifestations of glycoside poisoning, dyspepsia (diarrhea, nausea or anorexia), memory impairment and cognitive impairment, headaches, drowsiness, muscle weakness, and also gynecomastia, xanthopsia, impotence, feelings of euphoria or anxiety, psychosis, deterioration of visual acuity and other disorders of the visual analyzer function.

With the development of symptoms of glycosidic overdose, the treatment scheme is determined by the degree of severity of violations: if the symptoms have mild severity, a decrease in the dose of the drug is sufficient. With the progression of negative signs, the drug should be discontinued for an interval whose duration is determined by the dynamics of the symptoms of poisoning. In case of acute intoxication, it is necessary to conduct gastric lavage and consume a large amount of sorbents. In addition, the patient should take a laxative.

Ventricular-related arrhythmias are eliminated with IV KCl in combination with insulin. Potassium funds should not be used in case of slowing down of AV conduction. In case of preservation of arrhythmia, it is necessary to apply phenytoin in / in the way.

When bradycardia prescribed atropine. At the same time, oxygen therapy and drugs that increase the amount of circulating blood are used. Unithiol is the drug's antidote.

It must be borne in mind that intoxication can cause death.

[28], [29]

Interactions with other drugs

It is forbidden to combine Digoxin with acids, alkalis, tannins, as well as heavy metal salts.

Administration in conjunction with insulin, diuretic drugs, calcium salts drugs, GCS and sympathomimetics increases the likelihood of developing signs of glycoside poisoning.

Combination with amiodarone, quinidine, and erythromycin leads to an increase in blood levels of digoxin. Quinidine slows the excretion of the active element of drugs.

Verapamil, which blocks the activity of Ca channels, reduces the rate of renal elimination of digoxin, which is why the level of SG increases. This effect of verapamil is further gradually leveled (after a long simultaneous use of drugs - more than 1.5 months).

The simultaneous use of amphotericin B increases the risk of glycoside intoxication due to hypokalemia, which can develop under the influence of amphotericin B.

When hypercalcemia increases the susceptibility of cardiomyocytes against SG, which is why people using SG are not allowed to inject calcium medications intravenously.

The combination of the drug with propranolol, reserpine, and phenytoin increases the possibility of ventricular arrhythmias.

The level and therapeutic efficacy of drugs are weakened when combined with barbiturates or phenylbutazone. At the same time, the activity of Digoxin is reduced by potassium agents, metoclopramide, and drugs that decrease the gastric pH.

Concurrent use with gentamicin, antibiotics and erythromycin increases plasma values of glycoside.

The combination of the drug with cholestyramine, cholestipol, as well as magnesium-type laxatives weakens its intestinal absorption, which decreases the index of digoxin inside the body.

The rate of glycoside metabolism increases with the introduction along with sulfosalazine and rifampicin.

[30], [31], [32], [33], [34]

Storage conditions

Digoxin is required to be kept in a place closed to children. Temperature values range from 15 to 30 ° C.

[35], [36]

Shelf life

Digoxin can be used within a 36-month period from the moment the pharmaceutical product is manufactured.

[37], [38], [39]

Use in children

It is forbidden to prescribe pills in pediatrics.

Analogs

Analogues of the drug are drugs Celanid with Novodigalom.

[40], [41], [42], [43], [44], [45], [46]

Reviews

Digoxin receives a small amount of positive feedback. It is indicated that the drug has an extremely powerful effect and can be used exclusively under medical supervision.

But there are quite a few negative comments about Digoxin - they note that the drug does not have the desired effect, while leading to the development of many side effects.