The National Heart, Lung, and Blood Institute (NHLBI) has prematurely halted one arm of a major trial of hypertension drugs because patients taking one of the drugs—an α-adrenergic blocker—did not fare as well as patients taking a more traditional diuretic.
The main portion of the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) was designed to compare four classes of drugs: an α-adrenergic blocker (doxazosin), a calcium antagonist (amlodipine), an angiotensin-converting enzyme inhibitor (lisinopril), and a diuretic (chlorthalidone).
Stephenson J. Hypertension Trial Surprise. JAMA. 2000;283(15):1950. doi:10.1001/jama.283.15.1950-JHA00002-2-1