Coreg is part of a class of drugs called beta-adrenergic blocking agents, or beta blockers for short. As the name implies, these drugs block beta receptors in the body. Beta receptors are located in a number of places, including the heart and blood vessels. These receptors are what stress hormones (such as adrenaline) attach to and cause certain reactions in the body, such as an increase in:
- Heart rate
- The force with which the heart pumps blood
- Blood pressure (both systolic and diastolic).
By blocking beta receptors, Coreg causes the reverse effect of stress hormones. It decreases heart rate and both systolic and diastolic blood pressures, as well as the workload on the heart. This means that the heart requires less blood and oxygen to work properly. The medication also increases the efficiency of the heart, allowing more blood to be pumped out to the rest of the body.
Unlike a lot of other beta blockers, Coreg also blocks alpha receptors. The alpha blocker component of the drug works more on the peripheral blood vessels (arteries in the arms and legs). By blocking the alpha receptors, it relaxes these blood vessels.
A blood pressure reading consists of two numbers -- for example, 120/80. The top number is known as the systolic blood pressure, and the bottom number is the diastolic blood pressure. During clinical studies in people taking Coreg, systolic blood pressure decreased by 9 mmHg (millimeters of mercury), on average, and diastolic blood pressure decreased by 5.5 mmHg. The higher the dose, the greater the drop in blood pressure tended to be. By lowering blood pressure, Coreg can decrease the risks that often accompany long-term high blood pressure (see Effects of High Blood Pressure).
For people with mild to severe congestive heart failure, the effects of Coreg on the heart and blood vessels have been shown to:
- Decrease the progression of congestive heart failure
- Improve congestive heart failure symptoms
- Decrease hospitalizations and loss of life from congestive heart failure.
Following a heart attack, this medication has been known to decrease the chances of death, as well as the chances for another heart attack.