Used as an antiarrhythmic agent to treat irregular heart rhythms, particularly ventricular arrhythmias. It works by stabilizing the electrical activity of the heart, helping to maintain normal heart rate and rhythm. Tocainide hydrochloride is valued for its oral bioavailability and relatively rapid onset of action, making it suitable for both acute and chronic management of arrhythmias. It is considered an alternative to lidocaine, especially when long-term therapy is needed.