Patients need to have their potassium levels checked regularly, especially if they're also taking diuretics or potassium supplements. Diuretics are prescribed for almost all patients who are experiencing fluid buildup in the body and swelling in the tissues. A diuretic causes the kidneys to remove more sodium and water from the bloodstream than usual and convert it into urine. This helps to relieve the workload on the heart, since there is less fluid to pump throughout the body. It also decreases the buildup of fluid in the lungs and other parts of the body, such as the ankles and legs.
Different diuretics remove fluid at varied rates and through different methods.
Finding the right amount of fluid to remove from the body is often difficult. Too little means the person won't benefit from the diuretic, while too much puts patients at risk of fatigue, too-low blood pressure and poor kidney function. Doctors sometimes instruct their patients to weigh themselves daily and adjust the dose of their diuretic based on weight gains or losses due to fluid. Some types of diuretics also remove potassium from the body. Taking diuretics in the evening or at night often results in interrupted sleep, because the urge to empty the bladder continues for hours.