How does amiodarone first work?

Beta blocker: The first effect of amiodarone, seen in the first hours or days is the betablocking properties, slowing the heart rate.

Like a beta blocker: Amiodarone has some different effects. It both slows the heart rate down like a class of drugs called the beta blockers, and not long afterward, it also begins to regulate heart rhythm as well. When taking the drug by mouth, you may notice this effect anywhere between two days and a couple weeks; if you have been “loaded” IV, the effect will be much faster – typically within hours.