Metoprolol succinate, a beta-blocker, reduces blood pressure by slowing down the heart rate and decreasing the force of heart contractions. This lowers cardiac output, the amount of blood your heart pumps per minute. Simultaneously, hydrochlorothiazide, a thiazide diuretic, increases the excretion of sodium and water from the body through the kidneys. This reduces blood volume, further contributing to lower blood pressure.
Beta-Blocker Action: Slowing the Heart
Metoprolol selectively blocks beta-1 receptors in the heart. These receptors are responsible for stimulating the heart to beat faster and stronger. By blocking these receptors, metoprolol reduces sympathetic nervous system stimulation, resulting in a slower heart rate and decreased contractility.
Diuretic Action: Reducing Blood Volume
Hydrochlorothiazide acts on the kidneys, specifically in the distal convoluted tubules. It inhibits sodium reabsorption, leading to increased sodium and water excretion in the urine. This decrease in blood volume directly reduces the pressure exerted on blood vessel walls.
