What is a beta blocker and what does it do?

Beta blockers are a class of drugs that target the beta receptor. Beta receptors are found on cells of the heart muscles, smooth muscles, airways, arteries, kidneys, and other tissues that are part of the sympathetic nervous system. These blockers interfere with the binding of epinephrine to the beta site and weaken the effects of stress hormones. They slow down the heart rate and are used for high blood pressure, mostly.