Lowering Hypertension is Not Easy

High blood pressure treatment with thiazides may be effective in African Americans

(RxWiki News) African Americans often develop high blood pressure at earlier ages than others. A common medication may be a solution to keep pressure under control.

According to the Centers for Disease Control and Prevention, over 40 percent of African-American men and women have high blood pressure (hypertension).

Researchers have recently found that patients taking thiazide diuretics, an antihypertensive medication, were more likely to have their blood pressure under control.

"Ask your pharmacist about high blood pressure Rx."

Jane Harman, PhD, epidemiologist in the Division of Cardiovascular Sciences at the National Heart, Lung, and Blood Institute, evaluated hypertension treatments used by African Americans.

Participants were from the Jackson Heart Study, which is one of the largest investigations into the causes of cardiovascular disease in an African-American population. The study involved 5,300 men and women from Jackson, Mississippi. Participants were asked to bring in all of the medications they received.

At their first clinical examination (from the year 2000 to 2004), 2,415 participants were receiving medication for hypertension. At the second exam (from 2005 to 2008), 2,577 participants were receiving medication for hypertension. Many of the same patients were in both exam groups. More than two-thirds were women, and the average age was 60 in the first exam and 63 in second.

Among those who were receiving medication for high blood pressure, 66 percent from the first exam and 70 percent from the second exam had blood pressure readings below 140/90 mmHg. Generally, readings below this measure are considered adequate blood pressure control.

For patients with diabetes or chronic kidney disease, the standard for adequate blood pressure is 130/80, according to the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure.

Dr. Harman told dailyRx News, “We found that the people who were receiving thiazides – whether as a monotherapy (the only medication being given) or as one component of a polytherapy – were more likely to have their blood pressure under control than persons taking another type of monotherapy or polytherapy without thiazides.”

For example, persons receiving thiazide monotherapy were significantly more likely to have blood pressure under 140/90 (77 percent) compared with persons receiving monotherapy with ACE inhibitors (64 percent) or calcium-channel blockers (66 percent), the next most-commonly used hypertension medications used by participants.

Thiazides are the most commonly used oral diuretics, according to the National Library of Medicine. These medications reduce the amount of water in the blood and widen the coronary arteries, thus lowering pressure.

Compared to other hypertension medications, thiazides are quite inexpensive and available as generics, according to Dr. Harman. 

Commonly used thiazide diuretics include chlorthalidone (brand names Hygroton, Thalitone) and hydrochlorothiazide (brand names Microzide, HydroDIURIL).

ACE (angiotensin-converting–enzyme) inhibitors (brand names Lotensin, Capoten, Vasotec, Monopril) open blood vessels by blocking a vessel-constricting protein.

Calcium-channel blockers (CCBs) block calcium from moving into heart cells and blood vessel walls. This widens blood vessels and makes it easier for the heart to pump, which lowers pressure. A few common CCBs are amlodipine (brand name Norvasc), felodipine (Plendil) and isradipine (DynaCirc).

The authors noted that although CCBs are often considered to be effective monotherapy for African Americans, patients using CCB monotherapy were significantly less likely to be at target blood pressure than those using thiazide monotherapy.

The study was published online in April in The Journal of Clinical Hypertension.

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Review Date: 
April 4, 2013