The National Heart, Lung, and Blood Institute (NHLBI) halted one part of the large ALLHAT high blood pressure study because one of the drugs, an α-adrenergic blocker, was found to be less effective than the traditional diuretic in reducing some forms of heart disease (http://www.nhlbi.nih.gov/new/press/mar08-00.htm).
The ALLHAT study was designed to have 2 parts. One compared newer drug treatments for high blood pressure with more conventional and less costly treatment. The other compared treatments for high cholesterol.
The α-adrenergic blocker was doxazosin, and the diuretic was chlorthalidone. In the study, those who took doxazosin had 25% more cardiovascular events and were twice as likely to be hospitalized for congestive heart failure as those who used chlorthalidone. The drugs had similar rates of effectiveness in preventing heart attacks and in reducing the risk of deaths from all causes.
The federal agency took the action only after an independent data review by a committee specifically set up to do such monitoring was completed. Patients who were taking doxazosin were offered an alternative medication in consultation with their personal physicians.
“This finding adds important information to our understanding of antihypertensive drugs,” said NHLBI Director Dr Claude Lenfant, MD. “No large-scale blood pressure treatment study had ever compared these 2 classes of drugs. Earlier studies were small and could not, for example, detect an increase in patients’ risk of congestive heart failure.”
The other part of the ALLHAT study dealing with high cholesterol will continue until 2002, the time when the study was expected to end. The ALLHAT trial involves 42 448 patients enrolled in 623 clinics and centers in the United States, Canada, Puerto Rico, and the US Virgin Islands. The participants were ≥55 years of age, and 45% were women.
Because of the finding, the NHLBI advises patients with high blood pressure who are now taking an α-adrenergic blocker to consult with their doctors about a possible alternative. “Patients on an α-blocker for high blood pressure should see their doctors and not just stop taking the drug,” said Jeffrey Cutler, MD, director of the NHLBI Clinical Applications and Prevention Program and an ALLHAT project officer. “We cannot conclude that the drug was harmful. Rather, it didn’t work as well as the diuretic in reducing cardiovascular disease.”
- Copyright © 2000 by American Heart Association