Cheap hypertension drug works best. (Biomedicine).

An old-fashioned pill for preventing high blood pressure and some heart disease appears to work better than newer, more expensive drugs, according to the most recent research. In a 5-year study at 623 health centers, physicians compared the older drug, the diuretic chlorthalidone, with the drugs amlodipine and lisinopril.

Until now, researchers hadn't tested either of the newer drug types against a diuretic, which costs about 10 cents per pill. Amlodipine is a calcium-channel-blocker and lisinopril works by inhibiting a blood-pressure-related enzyme. These drugs range in price from 50 cents to $1.50 per pill.

The absence of a direct comparison has left doctors unsure of which treatment they should use, says Barry R. Davis of the University of Texas Health Science Center at Houston.

"The purpose of [our] study was to see whether [the newer] drugs' theoretical benefits would hold up as real benefits," explains Davis.

The researchers randomly assigned 33,357 people with hypertension to get one of the three drugs daily for at least 5 years. The male and female volunteers were all 55 or older but otherwise diverse.

"The biggest surprise was that the diuretic was better than the new medicines," says Davis. For example, participants taking chlorthalidone were 38 percent less likely to have heart failure compared with those taking amlodipine. And participants taking lisinopril had a more than 15 percent higher risk of having a stroke or heart attack than did people taking the diuretic.

The findings, which appear in the Dec. 18, 2002 Journal of the American Medical Association, prompted the National Heart, Lung, and Blood Institute to advise doctors to consider adding diuretics to their hypertensive patients' treatments or switching to the older treatment altogether.--C.M.