- Coreg CR is a once-a-day heart medication that is part of a class of drugs known as beta-blockers. Beta-blockers prevent beta-adrenergic substances such as adrenaline from activating parts of the nervous system, including the heart. Beta-blockers therefore relieve stress on the heart by slowing heart beat, decreasing the force of heart muscle contractions, and reducing blood pressure. Coreg has also been approved by the FDA for the treatment of hypertension and various other cardiovascular conditions.