Public Release: 

Calcium Channel Blockers -- Controversy In Treatment Revisited In Study By Boston Reseachers

American Heart Association

DALLAS, July 7 -- Boston researchers say they have evidence that supports the safety of nifedipine, a calcium channel blocker used to treat high blood pressure. Their report appears in the July issue of the American Heart Association journal Hypertension.

"Overall the safety of nifedipine did not differ significantly from the other agents. When nifedipine was used in combination with other drugs (diuretics and beta-blockers) it seemed to have a safety advantage," says lead author, William Stason, M.D. He is a lecturer in health policy management at the Harvard School of Public Health and consultant to Meta Works, Inc., a Boston group that generated the study.

When nifedipine was used alone, the risk of a cardiovascular event (death, non-fatal heart attack, stroke, increased chest pain, or treatment to reopen blocked arteries) was slightly, but not significantly increased.

"The results of our meta-analysis lend support to the safety of sustained-release and extended-release formulations of nifedipine in the treatment of hypertension, when they are used in combination with diuretics or beta blockers," he says. However, nifedipine patients were more likely to drop out of the study due to adverse side effects.

Calcium channel blockers have been used for decades to treat high blood pressure. However, two large studies in the past five years have generated concerns that they may be dangerous for some individuals, The two studies included an investigation that pooled data from 15 trials involving about 10,000 patients with unstable angina pectoris or heart attack and found an increase in deaths among patients taking a short-acting form of the calcium channel blocker nifedipine. An increase in the rate of heart attack was found in a second study that included patients with high blood pressure from the Group Health Cooperative of Puget Sound in the state of Washington. "These studies cast a pall over short-acting nifedipine," he says.

He and colleagues from Meta Works then conducted an investigation in which data from 98 studies that included 9,506 patients with high blood pressure were analyzed. A cardiovascular event was reported in 14 patients who received nifedipine compared to 24 patients who received other high blood pressure medicines. About 91 percent of patients were receiving the longer-acting form.

Randomized trials will be needed to confirm these results, says Stason.

Media Advisory: Dr. Stason can be reached at (617) 259-8939. Dr. Sarsan Ross of Meta Works can be reached at (617) 368-3575. (Please do not publish phone numbers.)

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