Diuretics, or water pills, are a class of drugs that doctors sometimes use to treat hypertension, or high blood pressure. According to the U.S. Department of Health and Human Services, diuretics are the best first defense against hypertension for older adults. There are three kinds of diuretics, potassium-sparing diuretics, thiazide diuretics and loop diuretics. All diuretics increase the amount of urine the body generates, but they do so in different manners.
High Blood Pressure
Blood pressure is the amount of force placed against arterial walls as the heart pumps blood through the body. There are two measurements. Systolic pressure is the amount of pressure exerted when the heart contracts, and diastolic pressure is the amount of pressure when the heart relaxes. According to the National Heart, Lung and Blood Institute, high blood pressure is when a patient's systolic rate is above 140 and his diastolic rate is above 90. High blood pressure is a serious condition that affects one in three Americans, according to the U.S. Centers for Disease Control and Prevention. Untreated high blood pressure can cause heart and kidney failure, stroke and other serious medical conditions.
Types of Diuretics
Sometimes diuretics can deplete potassium levels in the body. Potassium-sparing diuretics, such as triamterene and spironolactone, help preserve potassium levels but sometimes actually can raise potassium levels. This is why doctors often prescribe potassium-sparing diuretics in conjunction with a different type of diuretic. Thiazide diuretics, such as hydrochlorothiazide or chlorothiazide, stem from the compound benzothiadiazine. They block sodium and chloride absorption in the kidneys. Loop diuretics work on a specific part of the kidneys to block the absorption of sodium and chloride and are safe for patients with low kidney function.
Treatment
In the United States, the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure issues hypertension guidelines. The agency recommends that doctors first prescribe a thiazide diuretic to patients with high blood pressure. If a patient does not respond to thiazide diuretics, a doctor may prescribe a combination of diuretics or a diuretic with another type of drug such as an ACE inhibitor, medication that helps enlarge blood vessels and reduce blood pressure.
Side Effects of Diuretics
The most common side effect of diuretics is increased urination. The water loss may lead to weight loss in some patients. Taking diuretics also can lead to too much or too little potassium in the body and lower sodium levels. Another side effect is an increase in blood sugar and cholesterol levels. Joint pain, lightheadedness, sensitivity to sunlight and muscle pain are also side effects of diuretics.
Research on Diuretics
Diuretics were introduced in the 1950s. Since then, pharmaceutical companies have introduced new forms of this class of drugs, but the older drugs have withstood the test of time. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, or ALLHAT, study--which lasted from 1994 to 2002--had more than 40,000 participants and found that older, cheaper diuretics were more effective in treating hypertension than newer, more expensive drugs.
References
- U.S. Department of Health and Human Services: Diuretics Still Best Treatment
- National Heart, Lung, and Blood Institute: Hypertension Guidelines
- Centers for Disease Control and Prevention: High Blood Pressure
- National Heart, Lung, and Blood Institute: Reference Card
- National Institutes of Health: NHLBI Study Finds Traditional Diuretics Better
