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| |  DG DISPATCH - ESC 2000: Research Suggests Acute Coronary Event Risk With Long-Lasting Calcium Channel Blockers By Ed Susman Special to DG News AMSTERDAM, THE NETHERLANDS -- August 31, 2000 -- Calcium channel blockers should no longer be given as first line treatment for high blood pressure, researchers recommend after reviewing major trials in which the popular drugs were compared with other non-calcium channel blockers. Curt Furberg, MD, professor of public health science at Wake Forest University School of Medicine, Winston-Salem, NC, and a longtime critic of the calcium channel blockers, said that the drugs are so widespread in use that even a small increase in ill effects can cause widespread damage. He estimated that the drugs may be responsible for 85,000 excess acute coronary events. Dr. Furberg said that increase in adverse events -- primarily heart attacks and episodes of heart failure -- comes without any particular advantage to use of the drug in controlling high blood pressure. Milton Packer, director of the Heart Failure Center at Columbia-Presbyterian Hospital, New York, said, "I think Dr. Furberg has presented data raise a concern about the use of calcium channel blockers. The definitive answer is not in place. A meta-analysis can give an approximate answer to a question. I think this is the first step in an evolving process to find out what truly represents first line therapy." In scrutinizing nine studies, Dr. Furberg said the calcium channel blockers overall provided a reduction of .1 millimeter of mercury compared to the other medication classes -- diuretics, beta-blockers and ACE-inhibitors. "This minimal difference is statistically and clinically insignificant," he said at the 22nd congress of the European Society of Cardiology. "Since there is no overall blood pressure difference any differences in clinical outcomes must presumably be accounted for by non-blood pressure actions of the tested drugs." Dr. Furgberg said that record isn't good, either. Overall, patients who were taking calcium channel blockers had a 27 percent increased risk of having a heart attack, and had a 26 percent increased risk of having a episode of heart failure. The risk of people on calcium channel blockers to have a major coronary event was increased 11 percent. There was no added risk of stroke, mortality or dying from a heart attack, Dr. Furberg said, but there was no statistical advantage either. "Overall results of the meta-analysis of the nine hypertension trials show that the use of long- or intermediate-acting calcium channel blockers is associated with a significantly higher risk of acute myocardial infarction and heart failure compared to other anti-hypertensive agents," he said. "Since the calcium channel blockers are as effective as non-calcium channel blockers in lowering blood pressure, how can we explain the results?" he asked. "We now have emerging evidence that it matters how blood pressure is lowered. ACE-inhibitors appear more effective in preventing major in preventing major cardiovascular events in hypertensives with diabetes. Our meta-analysis of the calcium channel blockers add evidence that not all anti-hypertensive agents are equivalent in terms of their ability to prevent major disease outcomes." Dr. Furberg said he now believes that low-dose diuretics, beta-blockers and ACE-inhibitors remain the clear choice for first-line drugs in hypertension. "Due to their clinical inferiority, and high costs calcium channel blockers should be considered when first-line drugs have failed or cannot be tolerated." Hans Wedel, MD, professor of epidemiology and biostatistics at the Nordic School of Public Health, Goteburg, Sweden, said, "Meta-analyses are very powerful tools, but a very important issue is these analyses is the selection of the studies. There is always the possibility of bias in selection of these studies.
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