Furosemide, a loop diuretic, reduces blood pressure primarily by increasing urine output. This happens through a specific mechanism of action.
Mechanism of Action
Furosemide inhibits the sodium-potassium-chloride cotransporter (NKCC2) in the thick ascending limb of the loop of Henle in the kidneys. This blockage prevents the reabsorption of sodium, potassium, and chloride ions back into the bloodstream.
- Less sodium reabsorption means less water is reabsorbed. Increased excretion of sodium leads to reduced blood volume. Reduced blood volume directly lowers blood pressure.
Consequently, the kidneys excrete more water and electrolytes, resulting in a decrease in blood volume and subsequently, blood pressure.
Additional Effects
Besides directly impacting blood volume, furosemide also subtly affects other factors. It can:
Reduce blood vessel constriction (vasodilation): This further contributes to lowering blood pressure. Increase the excretion of calcium: While this is a less significant factor in blood pressure reduction, it’s worth mentioning.
The combined effect of these actions results in a noticeable reduction in blood pressure.
