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Older, Cheaper Drugs Best for Hypertension

Study finds diuretics work as well as ACE inhibitors, calcium channel blockers

TUESDAY, Dec. 17, 2002 (HealthDayNews) -- The older, less expensive blood pressure drugs called thiazide diuretics do a better job of saving lives than newer, costlier medications, a new study finds.

In an eight-year trial, the incidence of adverse events such as heart failure was lower and the risk of fatal heart disease or heart attacks was no greater for people who took a diuretic as for those who took a calcium channel blocker or an angiotensin-converting enzyme (ACE) inhibitor, says a report in tomorrow's issue of the Journal of the American Medical Association.

"Thiazide-type diuretics should be considered first for pharmacologic therapy in patients with hypertension [high blood pressure]," the report says. "They are unsurpassed in lowering blood pressure, reducing clinical events and tolerability, and they are less costly."

The drugs have different mechanisms of action. Diuretics lower blood pressure by increasing the excretion of water and sodium. Calcium channel blockers widen blood vessels by relaxing the muscles around them. ACE inhibitors block the activity of an enzyme that makes arteries constrict. Diuretics, by far the older drugs, generally are available as relatively inexpensive generics, while the calcium channel blockers and ACE inhibitors often are higher-priced, brand-name products.

The 50 million to 60 million Americans who have been diagnosed with high blood pressure now spend an estimated $15.5 billion a year on drugs to treat it, the report says. It does not estimate how much would be saved by wider use of diuretics, and it notes that a large proportion of patients need more than one drug. However, it adds that "it is reasonable to infer that a diuretic be included in all multi-drug regimens."

A preliminary cost analysis has been made, says study leader Dr. Jackson T. Wright Jr., a professor of medicine at Case Western Reserve University, and it shows that "if patients were switched from calcium channel blockers and ACE inhibitors to diuretics, the annual savings in direct costs would be between $250 and $600 per patient." There would be other savings from a reduced need for hospitalizations, Wright adds.

The study shows a diuretic is more effective than a calcium channel blocker in preventing heart failure and reducing the need for hospitalization, and that it is more effective than an ACE inhibitor in preventing stroke, heart failure and a number of other adverse events, Wright says.

The incidence of fatal heart disease or nonfatal heart attacks was virtually the same for all three drugs -- 11.3 percent for those taking the calcium channel blocker, 11.4 percent in those taking the ACE inhibitor, and 11.5 percent in those taking the diuretic.

The study "will lead physicians to rethink how they treat high blood pressure," says a statement by Dr. Daniel Jones, associate vice chancellor for health affairs at the University of Mississippi Medical Center and the American Heart Association's representative to the National Institutes of Health high blood pressure education program coordinating committee.

"But we strongly urge patients to continue taking their current medication until they have talked with their physician to determine the best treatment," Jones says.

Diuretics have fallen out of favor with many doctors because they have potentially dangerous side effects such as raising blood cholesterol and sugar levels, says Dr. Lawrence J. Appel, a professor of medicine at Johns Hopkins University who wrote an accompanying editorial.

However, the new study "provides strong evidence that they should be first-line therapy," he says.

The new study probably is the most comprehensive effort ever made to compare the effectiveness of different blood pressure drugs, Appel says.

"There have been many trials, but few have compared so many agents and none have had clinical outcomes as their endpoints," he says, meaning that earlier studies looked at how well the drugs reduced blood pressure, rather than their ability to reduce heart attacks and fatal heart disease.

The study enrolled more than 33,000 people with high blood pressure and at least one other risk factor for heart disease at 623 medical centers in the United States, Canada, Puerto Rico and the U. S. Virgin Islands. Some took amlodipine, a calcium channel blocker marketed as Norvasc, some took lisinopril, an ACE inhibitor marketed as Zestril or Prinivil, and some took chlorthalidone, a diuretic marketed as Hygroton or Thalitone but also available in generic form.

Appel says the study results will not change the way he practices because he has been a fan of diuretics from the start. One reason why many doctors have prescribed newer, more expensive drugs is that pharmaceutical companies advertise them heavily, while "there is little marketing of generics," he says.

What To Do

You can learn more about high blood pressure and how it is treated from the American Heart Association and the National Heart, Lung, and Blood Institute.

SOURCES: Jackson T. Wright, Jr., M.D., Ph.D., professor, medicine, Case Western Reserve University, Cleveland; Lawrence J. Appel, M.D., M.P.H., professor, medicine, Johns Hopkins University, Baltimore; Dec. 18, 2002, Journal of the American Medical Association
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