What is Coreg (Carvedilol)? Coreg (Carvedilol) is a beta-blocker. Beta-blockers affect the heart and circulation (blood flow through arteries and veins). Coreg is used to treat heart failure and hypertension (high blood pressure). It is also used after a heart attack that has caused your heart not to pump as well. Coreg may also be used for purposes not listed in this medication guide.