Cardiologists still debating
safety of calcium channel blockers
March 27, 1996
Web posted at: 11:55 p.m. EST
From Correspondent Andrew Holtz
ORLANDO, Florida (CNN) -- The debate about the safety of some drugs commonly used to treat blood pressure and heart problems went another round at a meeting of heart doctors in Florida this week.
The drugs, called calcium channel blockers, are taken by about 6 million people in the United States. A year ago, a furor erupted over a report saying that people taking some calcium channel blockers actually suffered more heart attacks.
This year, at the American College of Cardiology meeting, defenders of calcium channel blockers are firing back. Dr. Franz Messerli of Ochsner Medical Institutions was among those who stood up for the drugs.
"The long-acting calcium channel blockers are probably as safe as many other drugs used to treat hypertension," he said.
But new analyses don't convince critics that calcium channel blockers prevent heart attacks, strokes, and kidney problems caused by high blood pressure. Or, as Dr. Curt Furberg of Bowman Gray put it, "What's the evidence from large, randomized trials? Zero. There are no trials."
Researchers on both sides agree on some points: for instance, that most people with high-blood pressure should not be given what are called "short-acting" calcium channels blockers. And both sides agree there's more evidence backing other drugs, including diuretics and beta-blockers. However, some patients experience unpleasant side-effects from those older medications.
Researchers agree that calcium channel blockers should not be given to any patient with damage their heart's main pumping chamber.
"My surprise was how frequently these of drugs are used, were used then, in spite of lack of evidence they were effective in that particular population of patients," said Dr. John Kostis of the University of Medicine and Dentistry of New Jersey. Doctors say it is critical to focus on the details, such as just which patients are offered which drugs.
To many doctors, the key issue is that three out of four people with high blood pressure are not getting any effective treatment.
"We really have a long ways to go, and I think some of the newer agents may help improve the ability to control high blood pressure," said Dr. Robert Kloner of the University of Southern California.
The new reports tend to back up recent advice from a federal panel of experts that so-called long-acting calcium channel blockers are not dangerous when used properly.
Some doctors at the meeting said they're telling their patients to stick with the long-range treatment.
"I think the general feeling is: We should go ahead and use them still, especially the long-acting ones. The short-acting ones, nobody really uses for hypertension," said one doctor.
Another said he had talked to many of his patients about the long-term therapy, and encouraged them to wait until it has been looked into further.
Meanwhile, critics say they'll continue pointing to potential hazards of calcium channel blockers. A nationwide study of calcium channel blockers is under way, and it may settle the controversy. But results are at least a couple of years away. Until then, doctors and their patients must continue to make decisions, despite their uncertainty.
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