MONDAY, July 12, 2004 (HealthDayNews) -- New research refutes lingering fears that beta blocker drugs don't help patients with heart failure and might even be harmful for them.
The analysis of nine trials that included almost 15,000 patients showed beta blocker treatment was associated with a significant reduction in deaths. And very few patients had to stop using the drugs because of side effects, according to a report in the July 12 issue of the Archives of Internal Medicine.
"For many years, people considered beta blockers something that should be avoided in heart-failure patients because they could be very dangerous," said Dr. Harlan Krumholz, a professor of medicine at Yale University School of Medicine, who did the study in collaboration with Dr. Dennis T. Ko of the University of Toronto.
Beta blockers act by lessening the activity of adrenaline and other substances that increase the force with which the heart muscle contracts. The role of beta blockers in treating other conditions, such as high blood pressure and heart attacks, has never been in question.
But some cardiologists have been reluctant to use them for heart failure, a condition in which the heart progressively loses the ability to pump blood, because they can cause a temporary reduction in pumping ability. And there have been reports of damaging side effects such as dizziness, slower heart rate and dangerously low blood pressure.
"So we tried to put into perspective this side-effect profile," Krumholz said. "What we found was that while it is true that beta blockers increase the risk for lower blood pressure, dizziness and slower heart rate, the increase in risk is relatively small in absolute numbers."
The analysis found that only 11 patients in 1,000 experienced low blood pressure, 38 in 1,000 had a slower heartbeat and 57 in 1,000 reported dizziness, Krumholz said. But, he added, "we found that being on beta blockers made patients less likely to discontinue medication," indicating the side effects are not that severe.
The most important numbers showed that beta blockers do improve survival. Beta blocker therapy was associated with a 27 percent reduction in overall deaths in heart-failure patients, and also reduced the number of hospitalizations and progression of the condition, Krumholz said.
"What we hope is that this study gives physicians and patients a better picture of the side effects and benefits of beta blocker treatment," he said.
This finding is not new, said Dr. Kanu Chatterjee, a professor of medicine at the University of California, San Francisco, who wrote an accompanying editorial in the journal.
A Swedish trial done more than 25 years ago showed heart-failure patients benefited from beta blocker therapy, "but it never caught on," Chatterjee said. "I remember that when I was in England, a lot of famous cardiologists thought it was dangerous."
But during the past decade "a large number of clinical trials have unequivocally documented survival benefit of beta blocker therapy" in heart-failure patients, his editorial said. "It is thus indisputable that beta blocker therapy saves lives."
Like almost all other heart medications, beta blockers are not completely safe, Krumholz and Chatterjee said. Patients must be monitored carefully when treatment is started, Krumholz said. And Chatterjee recommended that doctors tell patients there might be a temporary worsening of symptoms when therapy begins, but that it will pass.
The Texas Heart Institute has more on beta blockers.