Battle of the High Blood Pressure Drugs

From the WebMD Archives

April 18, 2000 -- If you're among the one million Americans who use what's called an alpha-blocker to treat your high blood pressure, this story concerns you.

A preliminary result from a large national study looking at blood pressure medications finds the alpha-blocker Cardura is less effective in treating high blood pressure than the less costly and more conventional treatment, a diuretic. Diuretics decrease blood pressure by increasing urination.

There is nothing in the findings that state Cardura is harmful in any way, just that it is not as effective as a diuretic for treating high blood pressure.

The primary goal of the study was to evaluate heart disease, both fatal and non-fatal, and there was essentially little difference between the two drugs, one of the researchers, Charles Ford, PhD, tells WebMD.

An advisory committee from the National Heart, Lung, and Blood Institute (NHLBI), the sponsor of the study, recommended halting the part of the study that involved Cardura in late January. The basis of that decision is outlined in the April 19 issue of TheJournal of the American Medical Association.

The Cardura portion of the study involved just under 25,000 patients. Compared to the diuretic chlorthalidone, patients in the study using Cardura had 25% more heart problems and were twice as likely to be hospitalized for heart failure. The patients had slightly higher systolic blood pressures than the chlorthalidone group, and were less likely to take their medicine. Both drugs were similarly effective in preventing heart attacks.

The higher incidence of heart attacks and heart failure was "foremost", says lead author Barry R. Davis, MD, PhD, in deciding to discontinue with Cardura. Davis is with the University of Texas-Houston School of Public Health.

Gerald Payne, MD, NHLBI scientific project officer for the study, tells WebMD, "we can't say that [Cardura] causes these events ... It just doesn't prevent them as much as the diuretics. That's as far as we can state from this study," he says.

"Clearly, the diuretic was superior to [Cardura] in preventing ... heart failure and [Cardura] did not seem to be any better at preventing the other kinds of outcomes that we were looking at," Ford tells WebMD. He suggests that it might be a good idea to start with the diuretic and then keep Cardura "as a step two or step three drug to be added as needed." Ford is an associate professor of biometry at University of Texas-Houston School of Public Health.

According to a press release on the subject, the NHLBI is advising high blood pressure patients who take an alpha-blocker to consult with their doctors about a possible alternative. If a patient is just starting drug treatment, an alpha-blocker may not be the best choice for initial therapy. Other alpha-blockers in the same class as Cardura are Hytrin and Minipres. Ford doesn't say their recommendations apply to all alpha-blockers, but just that Cardura was chosen as a "representative member of that class of drugs."

But that's not the same as throwing the baby out with the bath water. "The last thing we would want to suggest is that patients should stop this drug," Jackson T. Wright Jr., MD, a vice-chairman of the study's steering committee told WebMD in a previous interview. "Patients need to contact their doctor to make sure they're on the best therapy for their high blood pressure." He says the findings do not necessarily mean the drug should not be used to control blood pressure, and they do not address the use of the drug for the prostate, a primary use. Wright is also a professor of medicine at Case Western Reserve University in Cleveland.

Louis Lasagna, MD, of Tufts University Medical School in Boston, called the findings "persuasive" with "important implications" in an accompanying editorial. He adds that, all else being equal, the diuretic, a very inexpensive drug, "appears to be a better choice than [Cardura]."

Pfizer, the manufacturer of Cardura, in a written statement has supported "the NHLBI decision to discontinue the Cardura arm" of the study.

Vital Information:

  • According to a new study, an alpha-blocker drug, called Cardura, is less effective for treating high blood pressure than the diuretic chlorthalidone, and Cardura does not protect patients from developing heart failure as well as the diuretic.
  • Patients taking Cardura, or other alpha-blockers Hytrin and Minipres, may want to consult with their physician about treatment, but these findings do not mean a patient should be taken off these medications.
  • Researchers cannot explain these study results, but suggest that people with high blood pressure try diuretics first.