After Decades of Use, Beta Blockers are Now Felt to be Harmful in Women

A new study suggests that this class of drugs is no longer helpful for women with heart failure.

Photo by Alexander Krivitskiy on Unsplash

What a difference a century makes. Over forty years ago, there was a consensus that after a heart attack, particularly if the heart muscle was weak, beta-blocker drugs were helpful. The BHAT study was published in 1982, when I began my first Cardiology practice. A relatively new class of drugs for high blood pressure and fast heartbeats, called beta blockers, had become popular. These drugs included names such as Inderal (propanolol) and Lopressor (metoprolol).

Data began to emerge that they could also help treat and extend the lives of patients with heart failure. At first glance, this sounded counterintuitive because heart failure was listed as one of the drug’s side effects. These drugs lower blood pressure and heart rate, and cause the heart to pump less vigorously.

The paradoxical benefit lies in another area. Beta blockers stunt or lessen the effects of adrenaline (epinephrine) circulating in the blood. Adrenalin is the body’s “fight or flight” hormone, produced in the adrenal glands. When a heart is not pumping well, as in congestive heart failure, there is a false signal given to the adrenal glands to produce more adrenaline. And chronically elevated adrenaline levels are harmful to optimal heart and blood vessel function.

The BHAT and many subsequent studies showed that administering beta blockers to patients with chronic heart failure may prevent worsening of their heart failure and extend their lives. The practice of routinely prescribing beta blockers after a heart attack and heart failure was so accepted that it became an integral part of all hospital discharge practices for these diseases.

That was until last month. The REBOOT study showed this long-held belief may be flawed. The study was deemed so important that it was published in two well-respected medical journals: The New England Journal of Medicine and The Lancet. Over 8,000 patients were enrolled in the study. They were admitted to over 100 hospitals in Spain and Italy. They had a heart attack and then developed poor heart pumping function. The latter predisposes them to heart failure.

The patients were randomly assigned to receive beta blockers or no beta blockers at hospital discharge. The remainder of their post-hospital care was identical. They were then followed for a median of four years. The results showed no difference in subsequent care. And of more concern, when the sexes were separated, women did slightly worse on the beta blockers than men.

The headlines won’t tell you this. However, the only subgroup that did worse was women with normal heart pumping function, and therefore, the results need to be looked at with a large grain of salt. The worse the heart-pumping function was, the better the patients, including women, did.

The bottom line is that beta blockers should still be prescribed after a heart attack, especially if a person’s ejection fraction (a sign of weak heart muscle) is low. Women with normal ejection fractions may not fare as well, but importantly, their rates of dying were not statistically different from those of men.

There is still much to unpack and study here. I look forward to future studies on this topic. However, since almost all beta-blocking drugs are now generic, it does not pay for the pharmaceutical companies to pay for and sponsor more studies. In years prior, the NIH and other public health institutions would do this. However, with RFK, Jr. as head of the HHS, I am not optimistic that this will get done any time soon.