Class IC Antiarrhythmic Drugs: Informed Choice

Abstract The article presents data on the most commonly used antiarrhythmic drugs of subclass IC: propafenone, flecainide, and a drug manufactured in Latvia — ethacizine. The features and priority areas of each drug use were identified. The author conducted a critical analysis of the results of Cardiac Arrhythmia Suppression Trials (CAST)-I and CAST-II and suggested ways to further study of subclass IC antiarrhythmic drugs in the context of current treatment strategies. The results of CAST-I and CAST-II should be interpreted in view of the heterogeneity of the subclass IC antiarrhythmic drugs and the fact that among the drugs of this subclass that are currently registered and approved for use in Ukraine, only flecainide was studied in CAST-I, and none of these drugs — in CAST-II. Ethacizine has a special position as a promising drug, especially effective in the treatment of vagus-induced heart rhythm disorders, with a small number of contraindications and drug interactions compared with propafenone and flecainide. Despite many years of use in several countries, this drug remains “invisible” to researchers around the world due to a limited number of international studies. The author draws attention to the need to re-evaluate antiarrhythmic drugs with an outdated evidence, in some cases quite limited, and to plan new experimental studies to clarify the possibility of subclass IC drugs to influence new pharmacological targets in arrhythmology, as well as large-scale well-planned studies of the safety and efficacy of subclass IC antiarrhythmic drugs in real present-day clinical practice.