Diuretics are a class of drug that increases the rate at which fluids are excreted from the body. They are used to treat a wide range of conditions, including high blood pressure, heart failure, polycystic ovary syndrome, certain kidney diseases, and edema. There are many side effects of diuretics, including increased urination and changes in levels of salts and other substances in the blood. Some of the side effects of diuretics are related to the type of diuretic being used.
There are three different classes of diuretics, which are referred to as loop, thiazide and potassium-sparing diuretics. Each type works in a different way and has different uses and side effects. For example, only thiazide diuretics work to reduce blood pressure. People who take diuretics might be prescribed a combination of two or three diuretics of different classes to help increase fluid excretion. People who take diuretics for high blood pressure often take additional blood pressure medications such as beta blockers or angiotensin-converting enzyme (ACE) inhibitors to further improve blood pressure.
Diuretics, in general, are considered a safe medication. The most common side effects of diuretics are increased urine output and increased excretion of potassium. Increased urine output occurs because the primary effect of these medications is increased loss of fluid from the body; the most efficient way for the body to excrete the fluid is via urine. Increased excretion of potassium and sodium also occurs.
The removal of large quantities of potassium from the body can be dangerous because this can cause disturbances in heart rhythm. For this reason, people who take loop or thiazide diuretics might also be prescribed potassium supplements. People who take potassium-sparing diuretics do not need potassium supplements, but they are at risk of hyerkalemia, which occurs as a result of excess blood potassium. To ensure safe potassium levels when taking diuretics, most patients have regular blood tests to monitor their electrolyte levels.
Changes in blood sugar and cholesterol also can occur when taking diuretics; normally these changes come in the form of an increase in these measurements. Side effects of diuretics that might occur specifically in men include impotence and gynecomastia, or enlargement of breast tissue. Women who take diuretics might experience irregularity in their menstrual cycle. These sex-specific symptoms generally are side effects of potassium-sparing diuretics rather than loop or thiazide diuretics.
Some side effects of diuretics are potentially dangerous if not treated. These include heart arrhythmia, blurred vision, mental confusion and skin rash. Other symptoms include persistent muscle cramps or muscle weakness, symptoms of dehydration, excessive or fast weight loss, easy bruising, persistent bleeding and ringing in the ears. Anyone who experiences one or more of these symptoms while taking diuretics should contact his or her doctor as soon as possible.