High blood pressure, a condition in which the pressure of the blood against the walls of the arteries becomes too high, increases the risk of coronary artery disease, heart failure, stroke and kidney failure. High blood pressure, also known as hypertension, affects one in three adults in the United States, according to the National Heart Lung and Blood Institute. Patients with hypertension consistently produce measurements of more than 140 mmHg systolic pressure over 90 mmHg diastolic pressure. Doctors can prescribe several types of medications to help lower blood pressure, including a class of medicines known as diuretics.
Primary vs. Secondary
Doctors classify hypertension as either primary or secondary, depending on the cause. Primary hypertension, which accounts for approximately 85 to 95 percent of the cases according to the Merck Manual, is caused by several contributing factors such as age, race, heredity, gender, diet, lifestyle and stress. Secondary hypertension occurs as a result of other medication conditions, such as kidney disorders, hormone disorders, thyroid disorders, tumors or medications. For those with secondary hypertension, taking diuretics may not control the high blood pressure as the underlying condition must be treated.
Role of Sodium
Diet plays a large role in the occurrence and treatment of high blood pressure. Sodium, more commonly called salt, enhances the flavor of food items and is essential for cellular functions. In excess; however, it increases the amount of fluid in the blood. In order to pump the excess fluid the heart must work harder, which increases the blood pressure.
Function of Diuretics
Diuretics, also known as water pills, induce the kidneys to remove excess salt, and therefore excess water, from the body. Normally, the kidneys filter the blood to remove waste products, salts and water. The kidneys remove much of the sodium from the blood, but as the collected urine passes through the ducts within the kidneys, approximately 65 to 70 percent of sodium reabsorbs back into the blood, according to Cardiovascular Pharmacology Concepts. Diuretic medications inhibit the reabsorption of sodium. The more sodium pulled out of the blood, the more water that goes with it, therefore helping to reduce blood pressure.
Types
Three main types of diuretic medications exist; thiazide diuretics, loop diuretics and potassium-sparing diuretics. Thiazide diuretics -- the most common class of diuretics prescribed to treat high blood pressure as indicated by the Merck Manual -- modestly reduce blood volume. Loop diuretics inhibit larger amounts of sodium from reabsorbing which causes larger volumes of urine but also leads to side effects such as lethargy, cramps, weakness and dizziness. Both thiazide and loop diuretics decrease potassium levels in the body, leading to the need for the third type, known as potassium-sparing diuretics. This type of medication works differently by interfering with the hormone aldosterone in the kidney, which removes sodium but does not affect potassium levels.
Other Medications
Other types of medications can effectively treat high blood pressure. Beta blockers reduce both the heart rate and the force with which the heart pumps, therefore reducing blood pressure. Calcium channel blockers cause blood vessels to dilate, which reduces pressure. ACE inhibitors inhibit the conversion of angiotensin I into angiotensin II --- a substance that narrows blood vessels.
