Question: I have been placed on an antiarrhythmic drug called sotalol for my heart rhythm problem. How does it work and what are the side effects? Answer :Sotalol is a commonly used antiarrhythmic drug that has been commercially available since the mid 1980's. It's a very unique drug that it blocks potassium channels in the heart but it also blocks adrenaline to the heart, so it's a beta blocker -- which are commonly used drugs -- in addition to being a potassium channel blocker.