Final answer:
To reduce heart rate in cardiac patients, a beta-blocker would be used. Beta-blockers like metoprolol and propranolol work by blocking beta-1 receptors to slow heart rate and lower blood pressure, and are particularly useful for treating hypertension and other heart conditions.
Step-by-step explanation:
A drug that might be specifically used to reduce heart rate in cardiac patients would be D) a beta-blocker. Beta-blockers are a type of sympatholytic drug that are utilized in the treatment of cardiovascular diseases. They operate by blocking the beta receptors, particularly the beta-1 receptor, on the heart responsible for increasing heart rate and blood pressure.
These medications allow blood vessels to dilate and prevent the heart rate from rising, thus improving cardiac function. Drugs such as metoprolol, which specifically targets the beta-1 receptor, and propranolol, which is a nonspecific beta-blocker, are common in clinical use. While beta-blockers are effective in managing hypertension and other cardiovascular conditions, caution must be exercised to avoid overprescription, which can lead to bradycardia and in severe cases, cessation of the heart's function.
It is important to differentiate between these and other compounds such as epinephrine and norepinephrine, which generally have the opposite effect, increasing heart rate and blood pressure.