If you have high blood pressure, your doctor may prescribe a diuretic, or water pill, to help manage your condition. The use of diuretics underlines how different systems in the body interact. Because all blood flow is directed through the kidneys, a relationship exists between the cardiovascular system and kidney function. Diuretics act specifically on urine production.
What Are Diuretics?
Diuretics are a class of drugs used to reduce water and sodium content in the body. Three basic types have different effects on kidney function. Thiazide diuretics reduce water content by increasing urine flow. Loop diuretics act on a specific structure within the kidney called the loop of Henle to control sodium reabsorption. Sodium increases water retention and thus blood volume. Potassium-sparing diuretics, as the name implies, increase urine flow but inhibit potassium excretion, a health risk when taking diuretics. They are commonly prescribed for treating high blood pressure, edema or swelling and glaucoma.
How Diuretics Work
Diuretics may inhibit certain actions to increase urine excretion. They may do this by blocking receptors on cells for different hormones, thus blocking their effects. By increasing urine production, blood volume decreases. This effect, in turn, lowers the workload on the heart and can help lower blood pressure. Diuretics are often the first course of treatment for hypertension. These effects illustrate the interconnected relationships between the systems of the body. In this case, the urinary, endocrine and cardiovascular systems all play a role in the effects of diuretics on kidney function.
Diuretics and Kidney Failure
Diuretics may have some medical applications for improving kidney function. A 2011 study by the Service de Néphrologie in Switzerland, published in the ""Revue Medicale Suisse," looked at the use of loop diuretics as a course of treatment for kidney failure. Because of the role of diuretics in increasing urine production, researchers postulated that they may compensate for the inadequacies in kidney function. While the study did not show the efficacy of using diuretics to improve kidney function, researchers recommended that diuretics can have other effective applications, such as for hypervolemia, a blood disorder of too much fluid in the blood.
Cautions
Doctors prescribe diuretics because of their relative safety. However, you must take some precautions when on these drugs. The change in blood volume due to water loss can cause low blood pressure. It may also impact cholesterol and blood sugar levels. If you are losing electrolytes, you might develop sodium or potassium deficiencies. With thiazide diuretics, you should avoid prolonged sun exposure. Discuss any unusual symptoms with your doctor if you are taking diuretics for any health condition.
References
- Drugs.com; Diuretics, Thiazide (Systemic); July 1, 1998
- Mayo Clinic; Diuretics; December 16, 2010
- "Principles of Anatomy and Physiology"; G. Tortora et al; 2005
- "Revue Medicale Suisse"; Diuretics in Acute Kidney Failure: Useful or Harmful?; J. Tataw and P. Saudan; March 2011
