Potential side effects of water pills, or diuretics, include a frequent need to urinate, severe fatigue, anomalous electrolyte levels, heart arrhythmia and muscle cramps, notes WebMD. Other possible side effects include blurry vision, dehydration, fever, rash and abdominal problems.
The purpose of water pills is to get excess water and salt out of the body through the urine, explains WebMD. This helps to reduce blood pressure and facilitate easier operation of the heart muscles. Water pills also treat heart failure, liver and kidney issues, and glaucoma, as well as other heart-related conditions.
Patients often need to urinate multiple times during the first few hours after taking water pills, notes WebMD. High levels of fatigue also set in, decreasing slowly while the body becomes accustomed to the medicine. Unusual levels of sodium, potassium and other electrolytes are also possible. People taking potassium supplements in addition to water pills often experience muscle cramping or weakness.
If dehydration sets in, the patient notices dark urine, dry mouth, severe thirst and dizziness, states WebMD. Some severe symptoms include fever, unexpected bleeding, ringing of the ears and unusual weight loss. If any of these symptoms appears, it's necessary to visit the doctor as soon as possible.