Thiazide diuretics are a class of medications commonly used to treat high blood pressure and fluid retention. They work by promoting the excretion of sodium and water from the kidneys, which helps to lower blood volume and reduce pressure on blood vessel walls. These medications are often prescribed for conditions such as hypertension and heart failure. Common examples include hydrochlorothiazide and chlorthalidone. While effective, thiazide diuretics can lead to side effects like electrolyte imbalances and increased urination, so monitoring by a healthcare provider is essential.