FRIDAY, Nov. 5, 2004 (HealthDayNews) -- Atenolol, a drug commonly prescribed to treat hypertension, doesn't prevent heart attacks or cardiovascular death any better than dummy drugs and is less effective than a wide variety of other blood pressure medications, a new study finds.
Not only should atenolol not be used to treat high blood pressure, it should not be used as a control drug to test other blood pressure drugs as it has been, researchers cautioned.
"We looked at all studies where atenolol is a first-line drug," said lead researcher Dr. Bo Carlberg from the Umea University Hospital in Sweden.
Carlberg's team reviewed four studies that compared atenolol, which belongs to a class of drugs called beta blockers, with a placebo. In these studies, there were a total of 6,825 patients, who were followed up for an average of four to six years. During that time, the researchers looked for death by any cause, cardiovascular death, heart attacks or stroke.
Atenolol was effective in lowering blood pressure. However, "Compared with placebo, atenolol did not decrease the risk of death of any kind, did not reduce the risk of cardiovascular death, did not reduce the risk of heart attack, but showed a clear, but not significant, tendency in reducing the frequency of stroke," Carlberg said.
The investigators also reviewed five studies comparing atenolol with other blood pressure drugs, including diuretics, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, and the angiotensin II antagonist, losartan.
In these studies, atenolol appeared to be not as good as these other drugs in preventing death, Carlberg said.
The report appears in the Nov. 6 issue of The Lancet.
Whether other beta blockers are as ineffective as atenolol is not known, Carlberg noted. "Our hypothesis is that atenolol is different from other beta blockers," he said. Carlberg doesn't believe other beta-blockers have the same problem as atenolol.
"Atenolol is a widely used drug," Carlberg said. "But the documentation about its effects on cardiovascular disease is weak. We suggest that it shouldn't be a first-line drug. There are many more effective antihypertensive drugs with much better documentation."
Carlberg added that atenolol should not be used as a reference drug in clinical studies, because it can make the test drug look more effective than it may really be.
"We don't promote atenolol," said Gary Burell, a spokesman for AstraZeneca Pharmaceuticals, which makes atenolol under the brand name Tenormin. "Atenolol has been out for a number of years, and you get new and improved molecules like Toprol-XL that show advantages over earlier drugs."
Toprol-XL is a new beta blocker that is being promoted by AstraZeneca for treating high blood pressure.
Burell noted that because atenolol is available as a generic drug, AstraZeneca no longer actively promotes it, although it still manufactures the drug. "There is no problem with atenolol," he said. "But there are no trials that show benefits that are seen with newer beta blockers like Toprol-XL."
The review "is a reminder that medical care can never be complacent," said Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine. "Atenolol is a drug long used in the treatment of hypertension. But since its introduction, many new drugs have come along, and some old drugs have been assessed in new ways."
Katz noted that rarely does a single paper warrant abrupt change in clinical practice. "But clinicians and researchers alike must keep their practice in line with the most current evidence," he added. "By this standard, it is indeed probable that atenolol is overused, and that the tailored selection of antihypertensive therapy can, and should, be improved."
The American Heart Association can tell you more about high blood pressure.