Poisoning with cardiac glycosides
Cardiac glycosides are cardiological herbal medicines, one of the main groups of drugs in the complex therapy of acute and chronic heart failure. These include Digoxin, Digitoxin, Strofantin, Korglikon, Celanid.
Source: depositphotos.com
The plant substrate for cardiac glycosides is foxglove, spring adonis, lily of the valley, jaundice, strophanthus, etc.
The main action of the funds of this group is cardiotonic, it is manifested by an increase in the force of contraction of the heart. In addition, a negative chronotropic (decrease in heart rate) and negative dromotropic (slowing down of the speed of nerve impulses through the tissues of the heart) effect are characteristic.
When used in therapeutic doses, cardiac glycosides reduce tachycardia, eliminate shortness of breath and edema accompanying heart failure, and improve peripheral blood circulation.
How does cardiac glycoside poisoning occur?
A dangerous undesirable effect when glycosides are taken in subtoxic or toxic doses is their ability to increase the excitability of cardiac structures, thereby provoking heart rhythm disruptions.
The main side effect of cardiac glycosides is glycosidic or digitalis intoxication, a life-threatening condition.
Poisoning with cardiac glycosides is common: to one degree or another, according to various sources, from 15 to 24% of patients receiving drugs are exposed to it. This is due to the peculiarities of absorption, distribution of glycosides in the systemic circulation and their excretion.
The therapeutic breadth (the interval between the minimum dose causing a therapeutic effect and the minimum dose causing side effects) is extremely small for the agents of this group, which significantly limits their use, despite their effectiveness.
The lethal dose is only 5-10 times greater than the dose that causes a therapeutic effect, and the first symptoms of intoxication appear when the therapeutic dose is exceeded by 2 times.
The development of acute glycosidic intoxication is possible in several cases.
Poisoning in persons receiving a therapeutic dose of the drug:
- elderly patients;
- patients with cardiac conduction disorders, unstable angina pectoris, acute myocardial infarction;
- persons with a history of hepatic, renal failure, hypothyroidism, electrolyte disturbances;
- in case of individual hypersensitivity to glycosides;
- taking cardiac glycosides is accompanied by the parallel intake of 3-4 or more other drugs, etc.
However, more often acute poisoning occurs when the drug is taken incorrectly:
- independent increase in the frequency of administration or dose;
- taking the drug without a doctor's prescription;
- taking by mistake instead of another drug;
- the use of cardiac glycosides for suicidal purposes;
- use by children during games.
Poisoning symptoms
Symptoms of acute poisoning with cardiac glycosides can be divided into 3 groups: dyspeptic, neurological and cardiac disorders proper.
Manifestations from the gastrointestinal tract are associated with the irritating effect of glycosides on the mucous membrane of the stomach and intestines:
- decreased appetite;
- nausea, vomiting;
- occasionally diarrhea.
Neurological disorders are manifested:
- rapid fatigue;
- headache, dizziness;
- severe drowsiness or, conversely, insomnia;
- nightmares;
- anxiety;
- convulsive syndrome;
- confusion, psychosis and delirium.
A characteristic manifestation of acute glycoside intoxication is specific visual impairment: yellow or yellow-green glow around objects (xanthopsia), intensifying when looking at a light source, decreased visual acuity, perception of objects in a reduced or enlarged form, photophobia, loss of visual fields.
Symptoms of acute poisoning with cardiac glycosides from the cardiovascular system are the most dangerous and are manifested, as a rule, by disturbances in heart rhythm and conduction:
- interruptions in the work of the heart;
- feeling of a sinking heartbeat;
- chest pain;
- severe weakness;
- lowering blood pressure;
- tachycardia, sometimes paradoxical bradycardia (less than 50 beats per minute);
- fainting episodes.
Most often, cardiac symptoms precede dyspeptic and neurological symptoms.
Source: depositphotos.com
First aid for cardiac glycoside poisoning
If glycosidic intoxication occurs during the injection with the drug, you should immediately stop its administration.
Acute poisoning with cardiac glycosides requires immediate action:
- Provide the victim with complete motor and emotional rest.
- Unbutton tight clothing, open the vents, providing fresh air.
- Take enterosorbent (Atoxil, Polyphepan, Enterosgel, Polysorb).
- Take a saline laxative (magnesium sulfate).
Gastric lavage in acute poisoning with cardiac glycosides is not recommended, since it can lead to an increase in parasympathetic tone and thereby aggravate the victim's condition.
When is medical attention required?
Since glycosidic toxicity is a serious, life-threatening condition, medical attention is required in all cases.
An ambulance team must be called if, while taking medications, symptoms appear from at least one of the systems (digestive, nervous, cardiovascular).
In a hospital, the victim will be provided with qualified assistance:
- correction of electrolyte disturbances (administration of potassium, magnesium, sodium preparations);
- oxygen therapy;
- introduction of specific antidotes (5% Unitol, Ethylenediaminetetraacetic acid, 2% sodium citrate solution);
- introduction of Antidigitoxin (Fab fragments of antibodies to digoxin), which completely eliminates cardiac disorders within 0.5-1 hour;
- the introduction of antiarrhythmic drugs, if necessary;
- with the ineffectiveness of antiarrhythmics - electrocardiostimulation and cardioversion.
Possible consequences
The main consequences of cardiac glycoside poisoning are rhythm and conduction disturbances that can lead to the death of the victim:
- atrial fibrillation and flutter;
- ventricular fibrillation;
- atrioventricular block;
- sharp bradycardia (less than 50 beats per minute);
- cardiac arrest (asystole).
Prevention
- Strict adherence to the doctor's recommendations when taking cardiac glycosides.
- Inadmissibility of independent, without consulting a cardiologist, taking drugs of this group.
- Systematic ECG control.
- A diet rich in potassium (the diet requires baked potatoes, dried apricots, raisins, bananas).
- Keep medicines out of the reach of children.
Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
