The National Heart lung and Blood Institute announced today (March 9, 2000) that is stopping one part of a large study called ALLHAT (Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack) because one of the drugs being tested, an alpha-blocker called Cardura (doxazosin) was associated with a higher rate of adverse cardiovascular events than one of the other drugs being tested- chlorthalidone, a diuretic. The patients taking doxazosin were 25% more likely to have an event, and were twice as likely to be hospitalized with congestive heart failure as the patients taking the diuretic. There was no increase of heart attacks or deaths with the Cardura, however. The systolic pressures were a little higher in the doxazosin patients, but the diastolic pressures were the same. The doxazosin group was also less likely to be compliant with the drug than the diuretic group.

The NHLBI staff said, 'We cannot conclude that the drug was harmful. Rather it didn’t work as well as the diuretic in reducing cardiovascular disease.'