These drugs are used to treat rhythm disturbances. However, they often have side effects, and so need to be carefully monitored. They can interact with other drugs, and even food and drink, such as grapefruit juice. So, be careful to tell the doctor all about what you are taking if he decides to initiate them.
Types of drug:
Class I: Quinidine, Mexilitine, Flecanide
Class II: Beta-Blockers
Class III: Amiodarone, Sotalol
Class IV: Calcium Channel Blockers, eg Diltiazem