Diuretics are a class of drugs used to treat patients with high blood pressure. Diuretics can cause blood vessel dilation, help the kidneys excrete water and salt, and decrease overall body fluid volume, according to Merck Manuals. All of these actions help lower blood pressure. Diuretics used for high blood pressure have been divided into three different groups: thiazide diuretics, loop diuretics, and potassium-sparing diuretics.
Thiazide Diuretics
The most commonly used diuretics, as reported by Cardiovascular Pharmacology Concepts, are the thiazide diuretics. This class of dug inhibits the reabsorption of sodium in the tubes of the kidney. Since the sodium is not taken back into the body, it is excreted in the urine. The loss of sodium increases the excretion of water. In this manner thiazide diuretics decrease the fluid levels within the blood vessels. A decrease in sodium and water leads to a decreased blood pressure.
Side effects of thiazide diuretics include low levels of potassium and magnesium, sexual dysfunction in men, high levels of calcium and uric acid, and stomach upset.
Some examples of thiazide diuretics include hydrochlorothiazide, Indapamide, and Metolazone.
Loop Diuretics
Loop diuretics, according to Patient UK, are less commonly used to treat high blood pressure when compared to thiazide diuretics. Loop diuretics work on a specific part of the kidney called the Loop of Henle. Loop diuretics decrease the fluid levels in the body by increasing the excretion of sodium and water. This is similar to the function of thiazide diuretics and achieves the same result: the lowering of blood pressure.
In low doses, loop diuretics produce few side effects. They can cause low blood levels of potassium, sodium, and magnesium. Increased levels of calcium have been measured in patients using loop diuretics. Dizziness, digestive discomfort, weakness, and confusion have also been linked to loop diuretics. The incidence of side effects rises as the dosage of loop diuretics is increased.
Furosemide, bumetanide, and ethacrynic acid are all examples of loop diuretics available to patients suffering from high blood pressure.
Potassium-Sparing Diuretics
Like most diuretics, potassium-sparing diuretics reduce the amount of water in the patient's body, as stated by Drugs.com. Potassium-sparing diuretics achieve this effect by increasing urine flow. The decrease in body fluid leads to a decrease in blood pressure. As their name suggests, potassium-sparing diuretics, increase urine flow, but also allow potassium to be spared from excretion. Most diuretics increase the amount of potassium released from the body, resulting in severely low potassium levels in the blood. Potassium- sparing diuretics allow patients to avoid this side effect.
Potassium-diuretics that are used to treat hypertension, or high blood pressure, include spironolactone, Amiloride, and triamterene.
