Harvard Health Letter: New thinking about beta blockers

If you have high blood pressure, there may be better alternatives.

Beta blockers, which slow the heart rate, are commonly prescribed to people who have had a heart attack and to people with heart failure or an irregular heartbeat. But for people with high blood pressure, beta blockers are no longer a first line of defense.

“It’s not that beta blockers don’t work for high blood pressure; it’s just that a variety of trials have shown the benefits of other medications,” says Dr. Joshua Beckman, a cardiologist and an associate professor of medicine at Harvard Medical School.

Benefits

Beta blockers interfere with, or block, norepinephrine and epinephrine (adrenaline), which are hormones that can cause your heart to pump faster and work harder. The medication can protect an injured or weakened heart from further damage, by keeping it from working harder.

While beta blockers are effective at reducing blood pressure, Beckman said that new research has shown that other medications are more effective at reducing blood pressure — particularly angiotensin-converting enzyme (ACE) inhibitors, angiotensin-receptor blockers (ARBs), calcium-channel blockers, and diuretics. Your specific medical needs will dictate which class of medications to control high blood pressure (called antihypertensives) your doctor will prescribe.

Risks

Taking a beta blocker may result in side effects. The side effects Beckman hears about most in the exam room are fatigue and erectile dysfunction. “These problems are real,” he says. “Older people complain about fatigue and middle-aged men complain about erectile problems.”

And there are other potential side effects. Beta blockers may mask low blood sugar if you have diabetes. When taken in very high doses, beta blockers can worsen heart failure, slow the heart rate too much, and produce wheezing and a worsening of lung disease. High doses may also cause lightheadedness from a drop in blood pressure, which puts people at risk for falls and injury.

One other note about beta blocker use: While the drugs are part of the standard treatment after a heart attack, it now appears that they can be discontinued three or four years after a heart attack.

What you should do

If you experience side effects while taking a beta blocker, tell your doctor. He or she may be able to switch you to another type of beta blocker, such as a long-lasting beta blocker or a shorter-acting beta blocker or a beta blocker that is less likely to affect the central nervous system.

If you’re taking a beta blocker for high blood pressure, it may be time to talk to your doctor about trying a different type of medication.

HARVARD HEALTH LETTERS is produced by Harvard Health Publications.