Diuretics, also called water pills, are first line treatment for blood pressure. These prescription drugs expel water and salts in urine via kidney. They are prescribed for heart failure, kidney failure, edema and liver failure. There are 3 types of diuretics; thiazides e.g. chlorothiazide and hydrochlorothiazide, loop diuretics e.g. furosemide and torsemide, and potassium-sparing drugs e.g. spironolactone and amiloride. Each type has different mechanism of action. Some side-effects of diuretics include hypokalemia, racing heart, dizziness, dehydration, muscle cramps, gout and headache.