Antiarrhythmic medicines may be used to return an irregular heartbeat (arrhythmia) to its normal rhythm, prevent an arrhythmia, or control the heartbeat during an arrhythmia. These drugs work mostly by slowing the heart rate or by helping the heart muscle tissue become stable.

Many antiarrhythmic medicines have side effects, and many interact with other medicines. A person taking any of these medicines should talk often with his or her doctor.