Commonly prescribed drugs called beta blockers fail to protect against heart attacks and strokes even while helping to control heart rate and blood pressure, researchers report in the Oct. 3 Journal of the American Medical Association. Beta blockers also didn’t lessen the odds of a heart-related death, in heart attack patients or others at risk, over a median follow-up of 44 months.
The American Heart Association had previously discouraged the long-term use of beta blockers for people with only risk factors or as a post–heart attack treatment beyond three years. The new findings further dim the prospects for drugs that have been a standard treatment for decades.
“I think this study is valid,” says Valentin Fuster, a cardiologist at Mount Sinai Medical Center in New York who wasn’t involved in the new study. Once seen as a leading treatment for heart attack patients, beta blockers are losing their luster thanks to new drugs and surgical devices, he says. When beta blockers were introduced several decades ago, statin drugs for lowering cholesterol and mesh stents for propping arteries open were unavailable.
Many patients in the new study — getting beta blockers or not — were also on other drugs. “The original beta blocker trials didn’t have all these medications and interventions,” Fuster says. “Therefore, [beta blockers] were the big winners.” The relative ineffectiveness of beta blockers in the new study reflects these other advances, he says.
Early studies had suggested that beta blockers prevented heart attacks, but many of those were short-term analyses, says study coauthor Sripal Bangalore, an interventional cardiologist at the New York University School of Medicine. He and an international team examined a registry of thousands of patients with either a history of heart attack, coronary artery disease or cardiac risk factors. When the researchers compared matching groups of people who differed mainly in whether they got beta blockers or not — nearly 22,000 participants in all — little or no difference emerged in rates of heart attacks, strokes or of dying from a cardiovascular cause.
In the group with only risk factors but no coronary artery disease, those getting beta blockers actually fared slightly worse than those not getting them, the data show.
Doctors should take heed, Bangalore says. For treating high blood pressure, he says, “I would say there are other medications.” And doctors prescribing beta blockers to prevent heart attacks in the belief they will save lives “may need to reconsider that option,” he says.
Beta blockers mute the effects of adrenaline, preventing the heart from revving and easing blood pressure. The drugs can cause headaches, fatigue, nightmares, poor exercise tolerance and sexual problems.
Beta blockers are still useful immediately after a heart attack and in patients with heart failure, a different condition in which the heart muscle has been damaged and overworked and struggles to pump out enough blood, the researchers note. “Decreasing the heart rate improves the efficiency of the heart muscle,” Fuster says. Also, scarred heart muscle and adrenaline can both contribute to heart arrhythmia, Bangalore says, and beta blockers seem to help there.