Poisoning with cardiac glycosides - symptoms, first aid, treatment, consequences: what to do and how to treat, reasons, what to take

Category: Drug poisoning

Therapy for heart disease is associated with certain difficulties in selecting medications and associated side effects. A fairly common complication is an overdose of cardiac glycosides.

Depending on the dose, this group of drugs can save the patient or provoke poisoning. The main difficulty in prescribing these drugs is their unpredictability, so treatment should be carried out under the supervision of a doctor who will promptly adjust the dose or discontinue the drug.

Classification and mechanism

Cardiac glycosides are obtained from plants (strophanthus, jaundice, lily of the valley, adonis, foxglove). According to their properties, they are divided into three types: non-polar (Digitoxin), polar (Korglykon, Strophanthin) and relatively polar (Celanide, Digoxin). This determines the difference in the effects of glycosides on the body.

When prescribing drugs for the treatment of cardiac pathologies, cardiologists take into account the periods of exposure to glycosides.

Three periods of glycosides:

Latent period. This is the time from the moment the patient receives the medicine until signs of its effect on the body.
Duration of therapeutic effect. This is the period from the manifestation of an action to its end.
The period of optimal action of the drug.

Digitoxin exhibits its therapeutic effect not as quickly as Strophanthin, but acts longer. The second is a fast-acting drug, but its effect is short-lived. Other glycosides are in the middle of the list of these drugs in terms of duration and speed of effect.

The speed of manifestation of the clinical effect depends on the dose taken and the method of treatment. Moreover, the greater the amount of medication and the shorter the latent period, the earlier intoxication will occur.

To avoid an overdose, a minimum amount of the drug is usually prescribed, at which a sufficient therapeutic effect is observed. The smaller the single dose of the drug, the less often complications occur during treatment.

For mild heart failure, the cardiologist prescribes a minimum dosage, and if the therapeutic effect is insignificant, he gradually increases it.

Dosage forms

The following digitalis products are currently produced by the pharmaceutical industry:

dried leaves powder;
Celanide and Digoxin solutions and tablets;
infusion of leaves;
tablets containing dry leaf concentrate;
tablets Cordigit, Digitoxin, Gitoxin (also powder);
Cordigit suppositories, Digitoxin.

Medicines Celanide and Digoxin are indicated in acute cases because they act quite quickly. Glycosides are administered intravenously to stop an attack; for chronic heart diseases, tablets are indicated.

The cardiotonic properties of digitalis after intravenous administration are observed after 15-30 minutes, with oral administration - after 1.5-2 hours.

The second advantage of digitoxin is its pronounced ability to slow down heart contractions. Atrial tachyarrhythmia, when the blood circulation is impaired, turns into bradyarrhythmia, the pulse deficit decreases or completely disappears, the blood flow speed increases, both in the pulmonary circulation and in the large one, venous pressure decreases, daily diuresis increases, and body weight decreases.

Digitoxin also affects blood vessels, as a result of which the vessels of muscles, skin, and kidneys dilate, and the areas of blood vessels innervated by the celiac nerve narrow, which leads to redistribution of blood mass in different organs and tissues. Dilation of renal vessels and improvement of hemodynamics contributes to the pronounced diuretic effect of the drug. The amount of circulating blood also normalizes, but gradually.

Direct coronary blood flow increases due to lengthening of diastole and shortening of systole. Digitoxin, compared to other cardiac glycosides, binds most strongly to serum albumin, which causes cumulation (along with its slow elimination from the body), more pronounced than other cardiac glycosides.

hypertension;
cardiosclerosis;
heart defects;
myocardial dystrophy;
acute heart failure.

certain types of paroxysmal tachycardia;
diseases with atrial fibrillation;
stage II circulatory failure.

Digitoxin is indicated orally, treatment according to medical indications and purely individually.

Gitoxin has a pronounced cardiotonic effect, which manifests itself in increased and shortened systole, lengthened diastole, and helps slow heart contractions. Gitoxin is indicated for heart failure II and III (the etiology is different), usually in forms with the presence of atrial fibrillation. Gitoxin is indicated orally, starting with a dose of 0.0003–0.0004 g per day, then the dose is reduced per day to 0.0002–0.0001 g. If treatment is effective, a maintenance dose is usually selected, in each case individually, and taken for a long time.

When using cordigitate, the systolic effect of digitoxin is quickly recorded, the rhythm slows down, the pulse deficit is eliminated, and diuresis increases. When the drug is discontinued, bradycardia disappears after 2–4 days. The therapeutic effect of cordigititis is expressed especially in the tachysystolic form of atrial fibrillation, in the case of thyrotoxic heart lesions, as well as in atrial flutter with conduction block 2:1. But sensitivity to cordigititis varies quite widely; as for the dosage, it is strictly individual.

The drug Cordigitit is indicated orally, 1/2 to 1 tablet two to four times a day.

Strophanthin

This drug is obtained from tropical vines. Strophanthin has a quick but short-term effect. When taken orally, it is ineffective, so it is prescribed intravenously in emergency conditions. It is used for acute heart failure, as well as for the treatment of severe forms of chronic heart failure, especially when digoxin is ineffective. Its advantage is the possibility of use even in the bradysystolic form of atrial fibrillation. Side effects of the drug are nausea and vomiting, as well as rhythm disturbances.

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Strophanthin is contraindicated in severe organic diseases of the heart and blood vessels, acute myocarditis, endocarditis, and severe cardiosclerosis. It should be used with caution in case of thyrotoxicosis in combination with atrial extrasystole due to the risk of developing atrial fibrillation.

Overdose of cardiac glycosides: causes

Intoxication with cardiac glycosides is more common in adults during treatment.
Suicide attempts are much less common. Accidental poisonings occur when a person unintentionally consumes the plants in question. This happens more often in children. A 5-fold overdose of cardiac glycosides can cause death, i.e. significantly more than the average therapeutic dose prescribed by the cardiologist.

In the presence of chronic diseases or any pathological conditions, sensitivity to intoxication with glycosides increases. Predisposition to complications:

pre-infarction or post-infarction state;
liver or kidney dysfunction;
advanced age;
potassium or magnesium deficiency;
thyroid diseases;
undergone open heart surgery.

Before prescribing cardiac glycosides, the doctor carefully collects and evaluates the medical history, existing symptoms, and then determines the dosage. Glycosides, for example, Digoxin, tend to accumulate in the body, and poisoning may appear 1-2 weeks after the start of treatment. Therefore, the initial dose is slightly larger than the subsequent one.

If cardiac glycosides are prescribed to elderly patients, then close people should monitor the use of the drug. This age group of patients has memory problems, and they may take an additional dose of medication, which can lead to an overdose.

Review of drugs used for intoxication with cardiac glycosides

While the patient is in the clinic to eliminate the consequences of an overdose of cardiac glycosides, he is individually prescribed drugs that restore the body. Treatment depends on many factors: age, timing of drug use, liver and kidney function, and the presence of chronic diseases.

Without fail, after taking the antidote (the purpose of the antidote depends on the severity of intoxication), toxins are removed with adsorbents: activated carbon, Enterosgel, Sorbex. Other drugs prescribed for poisoning may include:

to eliminate hypokalemia, replenish potassium in the cardio organs, against dehydration - potassium chloride, insulin, glucose, Panangin, potassium orotate, Asparkam;
for bradycardia (slow heart rate), vomiting, nausea - Atropine, which increases heart rate. It must be taken into account that Atropine is contraindicated in tachycardia, as is the use of adrenaline (to avoid ventricular fibrillation);
the drug magnesium sulfate, provided that there are no problems with the kidneys;
for the formation and removal of calcium compounds that disrupt the functioning of blood vessels - Trilon B, citrate salts;
to stop arrhythmia - Propranolol, Lidocaine, Anaprilin, Novocainomide. Eliminates ventricular arrhythmias Phenytoin;
if necessary, anticonvulsants Aminosin, sodium hydroxybutyrate, Sibazon are prescribed;
carry out oxygen therapy, eliminating oxygen starvation of organs;
Prescribe vitamin therapy with vitamin E, group B, to maintain the functioning of the cardiovascular system Riboxin, Aspicard.

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Symptoms and diagnosis of overdose

Digoxin is most often prescribed from this group of drugs. Previously, it was used everywhere, but now high doses of Digoxin are almost never used, and heart rate control is carried out using calcium antagonists and beta blockers.

Signs of overdose are more often observed in older people; they occur even when using an average therapeutic dose, especially in the presence of the predisposing factors mentioned above.

During treatment with drugs of this group, changes in the ECG are often observed, but they cannot be considered as a sign of poisoning. These effects persist for several days after the end of taking cardiac glycosides.

Symptoms of overdose with cardiac glycosides:

Arrhythmia, bradycardia, atrial fibrillation, decreased heart rate.
Visual impairment.
Lack of appetite, nausea, vomiting, diarrhea.
Drowsiness, headache.

The diagnosis (ICD-10 code: T46.0) is poisoning with cardiac glycosides, most often an overdose of Digoxin with atrial tachycardia or dysfunction of the sinus node.

Clinical signs of digitalis intoxication

Signs of an overdose of cardiac glycosides are mostly observed in cardiac activity. Manifestations of intoxication consist of cardiovascular syndrome. Symptoms of neuropsychiatric and gastrointestinal lesions are also present.

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First, the contractility of the myocardium changes, and a disturbance in heart rhythm occurs.

Main manifestations of overdose:

pain in the heart area of a compressive nature disappears without treatment after 10-15 minutes;
lack of appetite;
interruptions in heart rhythm;
sharp pain in the abdomen;
tachycardia;
nausea, vomiting, stool upset;
headache (migraine type);
indifference, weakness;
flashing “flies” before the eyes;
deterioration of visual acuity;
a sharp drop in blood pressure;
body cramps;
confusion, coma.

Patients may experience hallucinations and other mental disorders. The severity of mental disorders is influenced by the severity of the patient's condition.

Rules for the treatment of acute poisoning

In case of severe intoxication with glycosides, resuscitation measures should be aimed at reducing the concentration of the drug in the gastrointestinal tract.
Urgent Care:

Gastric lavage with saline solution and administration of a sorbent that prevents absorption of the substance into the gastrointestinal tract.
In case of intoxication with Digitoxin and Isolanide, Vaseline oil is used to reduce circulation.
To avoid aspiration of vomit, the patient takes a position on his side.

An ambulance should be called at the first signs of poisoning, since an overdose of cardiac glycosides can only be treated in a hospital setting.

Pharmacotherapy in a hospital setting:

Unithiol and tocopherol are administered in individual dosages.
Oxygen is given, insulin and glucose are administered.
The heartbeat is normalized with drugs of an antiarrhythmic mechanism of action, except for Quinidine and Novocainamide. If treatment fails, defibrillation is performed.
Potassium supplements are prescribed.
They give antiemetics (Diprazine, Promedol).
Sodium citrate is used as an antidote that stops or weakens the effect of the glycoside.
For severe arrhythmia, an injection of atropine is indicated.
For tachycardia and pain, Verapamil is administered.

After resuscitation measures, when the victim’s condition has stabilized, he is left under observation for several more days. If improvement occurs within 24 hours, then conclusions can be drawn about a favorable outcome.

Treatment

The main help for any intoxication is to stop toxic drugs from entering the body. Untimely first aid can lead to serious consequences even before doctors arrive (the patient may fall into a coma or die).

Rinse the stomach several times;
Give the victim activated charcoal or a weak salt solution;
Ensure fresh air enters the room;
Poisoning with glycoside drugs requires treatment in a hospital, so it is recommended to immediately call an ambulance.

All measures to save the patient can be individual in nature. After the symptoms of poisoning disappear, the patient remains in the hospital for several days. The prognosis is considered favorable if, within 24 hours after poisoning, the victim’s condition returns to normal.

!Medical assistance to a victim of toxic substances should be provided immediately when the first symptoms of poisoning appear.

Cardiac glycosides are most effectively used to treat heart failure. These are preparations containing plant extracts and various types of sugars.

Glycosides stimulate the heart muscle, increasing contractions when its work is insufficient. The therapeutic use of these drugs in the treatment of the heart muscle has a positive effect on the functioning of the myocardium.

The most well-known and frequently prescribed drug from this group is Digoxin.

! Cardiac glycosides are potent drugs containing poison, a small amount of which treats cardiac disorders, and an overdose can lead to death.

Signs of poisoning with cardiac glycosides are common (almost every 4 patients).

abnormal heart rhythm (atrial fibrillation, bradycardia);
disruption of myocardial function causing oxygen starvation (tachycardia);
slowing of blood flow manifested by swelling of the legs and shortness of breath.

TOXIC EFFECT OF CARDIAC GLYCOSIDES

Cardiac glycosides are potentially one of the most toxic drugs. They have an extremely low therapeutic index - the toxic dose is 50-60% of the therapeutic dose. Every fourth patient taking cardiac glycoside drugs experiences symptoms of poisoning. The reasons for this may be:

1) low therapeutic index;

2) non-compliance with existing principles for the use of cardiac glycosides; 3) combination with other drugs:

- when cardiac glycosides are used together with diuretics, a loss of potassium occurs, promoting hypopotassium histia, which significantly reduces the threshold of excitability of cardiomyocytes, and as a result, a violation of the heart rhythm (extrasystole) occurs;

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- combined use of cardiac glycosides with glucocorticoids also leads to potassium loss with a corresponding disturbance in heart rhythm;

4) severe damage to the liver and kidneys (sites of biotransformation and excretion of glycosides);

5) individual high sensitivity of the patient to cardiac glycosides, especially during myocardial infarction.

The mechanism of development of intoxication with cardiac glycosides is that toxic concentrations of cardiac glycosides, significantly reducing the activity of membrane ATPase, disrupt the function of the potassium-sodium pump. Enzyme inhibition results in:

a) to disruption of the return of potassium ions into the cell, as well as to the accumulation of sodium ions in it, which contributes to increased excitability of the cell and the development of arrhythmias;

b) to an increase in the input and disruption of the output of calcium ions, which is realized by hypodiastole, leading to a decrease in cardiac output.

Symptoms of intoxication are divided into:

I. Cardiac symptoms of intoxication:

2. Atrioventricular blockade (partial, complete, transverse).

II. Extracardiac (extracardial) symptoms of intoxication:

1. From the gastrointestinal tract: loss of appetite, nausea, vomiting, abdominal pain. These are the earliest symptoms of gastrointestinal intoxication.

2. Neurological symptoms (it is associated with excessive bradycardia that occurs with an overdose of cardiac glycosides): adynamia, dizziness, weakness, headache, confusion, aphasia, impaired color vision, hallucinations, “trembling of objects” when examining them, loss of visual acuity.

In case of intoxication with cardiac glycosides, you should:

1. Immediately discontinue cardiac glycoside drugs with simultaneous administration of activated charcoal, gastric lavage, and saline laxatives should also be prescribed.

2. Temporarily cancel drug combinations. If the patient's condition is severe, use antiarrhythmic drugs. In a hospital setting, you can prescribe (4-5%) a solution of potassium chloride, intravenously, by drip, under ECG monitoring.

3. Prescribe diphenin to the patient - a drug that stimulates microsomal liver enzymes and has a good antiarrhythmic effect. Currently, this is one of the best drugs for ventricular tachycardia caused by digitalis intoxication. Lidocaine (xicaine) is less effective for intoxication with cardiac glycosides than diphenine. Sometimes, in order to combat intoxication with cardiac glycosides, beta blockers (for example, anaprilin) are used. You can also prescribe unithiol, which is a donor of sulfhydryl groups, solutions of Trilon B, which binds ionized calcium, as well as specific antibodies to cardiac glycosides. The latter, in the form of commercial drugs (fragments of monoclonal antibodies to cardiac glycosides), are, in fact, antidotes.

5) individual high sensitivity of the patient to cardiac glycosides, especially during myocardial infarction.

Consequences and prevention

The prognosis for the victim depends on the following factors: the dose of the drug, the frequency of doses, the quality of first aid provided at home, the speed of resuscitation measures, the presence or absence of chronic pathologies.

Prevention of poisoning:

Use cardiac glycosides as prescribed by a doctor, strictly adhering to the dosage.
Providing reliable information to the cardiologist about drugs used to treat concomitant pathologies.
Treatment is monitored by ECG and blood electrolyte levels (especially potassium).
Introducing potassium-rich foods into the diet.