Antiarrhythmics are drugs used in the treatment of cardiac arrhythmias. Antiarrhythmics are divided into five classes, each with different mechanism of action and specific toxic effects that can lead to serious health problems, even death. The first part of this paper provides an overview of the pharmacological properties of antiarrhythmics according to classes: class I blocks fast sodium channels, class II includes β-blockers, class III affects potassium channels, class IV blocks calcium channels, and class V includes specific drugs such as digoxin, adenosine, magnesium sulfate, atropine, and others. Their mechanisms of action, indications, and side effects are described in detail. The central part of the paper talks about the epidemiology of drug poisonings, particularly antiarrhythmics, analyzing the frequency and causes of such poisonings. Special attention is given to the methods of treating antiarrhytmic poisonings. For each class of antiarrhythmics, dosage, symptoms, and signs of poisonings are described, including cardiovascular, gastrointestinal, neurological and other systemic effects, along with specific protocols for first aid and medical interventions. The use of antidotes is also discussed, as well as supportive therapies such as intravenous fluid and electrolyte replenishment, medical activated charcoal, and other supportive measures. The paper also analyzes modern therapeutic approaches, including hyperinsulinemia-euglycemia therapy ( HIET ) with high-dose insulin ( HDI ) and intravenous lipid emulsion therapy.