Beta-Blockers’ Side Effects Relatively Rare, Study Says
A class of highly effective heart drugs called beta-blockers have developed a reputation for causing depression, impotence and fatigue. But a new study has found that the drugs’ reputed side effects have been overblown.
The study of 15 trials involving 35,000 patients was conducted by researchers trying to understand why so many physicians are reluctant to prescribe beta-blockers, even though they lower blood pressure; improve heart function and survival in patients with heart failure; and reduce deaths after heart attacks by 20%. By blocking the effects of stress hormones on the heart, beta-blockers slow the heart rate and the force of contraction, easing the heart’s workload.
Dr. Harlan M. Krumholz, a cardiologist at the Yale University School of Medicine, had found in a 1995 study that 50% of heart attack patients who could benefit from beta-blockers weren’t getting them; he estimates that figure could be as high as 75% today.
Krumholz and his colleagues figured that perhaps doctors were being deterred by side effects long associated with beta-blockers like Inderal (propranolol), Tenormin (atenolol) and Lopressor (metoprolol). Although the FDA-approved package inserts prepared by drug manufacturers warn about the side effects, Krumholz said, “most of the conventional wisdom was anecdotal. There was no systematic review of this association.”
So he and his colleagues decided to review published studies to see whether study subjects actually suffered more of those side effects than people not taking them.
In findings published in last week’s Journal of the American Medical Assn., the researchers reported no increase in depression among those taking the drugs compared with those taking a dummy pill. About 1 in 5 people in either group had depressive symptoms.
Fatigue was more significant, affecting about 1 in 3 patients taking the medications and just more than 30% of those getting a placebo. That translates into one additional report of fatigue for every 57 patients treated with beta-blockers for a year. (The authors noted that older beta-blockers accounted for more fatigue than more recently developed pills.)
Sexual dysfunction--such as loss of desire and impotence--affected more than 1 in 5 patients on beta-blockers and slightly fewer study subjects on placebos. The drugs were associated with one extra report of sexual dysfunction for every 199 patients taking them.
In addition to beta-blockers, several other classes of medications are used to lower blood pressure and treat heart failure. One of them, the calcium channel blockers, relax blood vessels, increase the amount of oxygen to the heart and reduce the heart’s workload. Drugs known as ACE inhibitors, or angiotensin-converting enzyme inhibitors, relax blood vessels and prevent retention of salt and water. The newer angiotensin II receptor blockers also relax blood vessels.
