Thiazide Diuretics: How They Help Lower Your Blood Pressure

Thiazide diuretics are among the medications doctors may prescribe to lower blood pressure. Diuretics are also called water pills because they reduce fluid buildup in the body.

Diuretics cause the kidneys to release more sodium, or salt, into the urine so it is eliminated along with water from the blood, the Mayo Clinic explains.

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The three types of diuretics include thiazide, potassium-sparing, and loop. Each one focuses on a different part of the kidneys depending on a patient’s blood pressure condition.

A doctor might prescribe such thiazide diuretics as hydrochlorothiazide (Microzide), chlorothizide (Diuril), chlorthalidone, indapamide, or metolazone.

Thiazide diuretics reduce the accumulation of fluids in the body, MedicineNet notes. The medication inhibits the kidneys from reabsorbing salt and water from urine and into the body. Those substances are then flushed from the body through urination.

The effect on the kidneys from thiazide diuretics is relatively moderate, according to Patient. There may not be a noticeable increase in urination compared with other medications. The drugs interfere with the kidney process just enough to eliminate more fluid from the body.

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The low dosage used in thiazide diuretics avoids getting up to urinate in the middle of the night. The pills are usually taken once a day, which helps to reduce blood pressure during a 24-hour period.

Thiazide diuretics also have the ability to widen blood vessels, another effect that helps to reduce blood pressure. They help reduce fluid retention for conditions such as heart failure and edema.

Because of the low dose, side effects are uncommon, Patient explains. However, some people with diabetes might need increased treatment because of a possible hike in blood sugar levels. People with gout could experience an increase in uric acid levels while taking thiazide diuretics.

A salt imbalance may occur with thiazide diuretics, causing low levels of certain minerals, so a blood test might be necessary. Other possible side effects of thiazide diuretics include dizziness, upset stomach, sensitivity to sunlight, and impotence that ends by stopping treatment.

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