Diuretics 101

Diuretic Types and Side Effects

Most people with high blood pressure get relief from thiazide diuretics.
Most people with high blood pressure get relief from thiazide diuretics.
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Each of the three main types of diuretic medicines works a little differently, but they all lower the amount of salt and water in the body, which helps to lower blood pressure. The choice of diuretic depends on the condition for which it is being prescribed. Urine flow usually increases within hours of the first dose, but diuretics may take several weeks to treat conditions like high blood pressure. The three main types of diuretics are:

Side Effects of Diuretics

The most common side effect associated with diuretics is an increased elimination of potassium, resulting in a dangerously low level of potassium in the body. With the exception of potassium-sparing versions, all diuretics may cause a loss of potassium, which, if left untreated, increases the risk for heart rhythm disturbances that can be serious. Taking a potassium supplement or eating high-potassium foods (such as bananas and orange juice) may help maintain healthy potassium levels. A potential side effect of potassium-sparing diuretics is a dangerously high level of potassium in people who already have a high potassium level or who have kidney disease. Other potential side effects of diuretics include:

Generally, older patients may be more susceptible to side effects of diuretics and may require lower doses and close observation, but they are routinely prescribed these medications.

A good number of patients taking diuretics develop a resistance to them. We'll discuss diuretic resistance on the next page.­