For more than half a century, drugs known as beta blockers have been a mainstay in managing heart disease, especially for heart attack survivors. But doctors are now reconsidering this strategy, based on growing evidence showing that for some people who have had a heart attack, beta blockers may not provide any meaningful benefit. “For people whose hearts are still pumping normally after a heart attack, doctors may now think twice about prescribing a beta-blocker,” says Dr. Cian McCarthy, a cardiologist at Harvard-affiliated Massachusetts General Hospital.
Sometimes, however, a heart attack leaves the left ventricle (the heart’s main pumping chamber) unable to contract effectively. When that’s the case, beta blockers are still recommended, he says. These drugs are also prescribed to treat angina (chest pain caused by narrowed heart arteries), to treat heart failure, to suppress abnormal heart rhythms such as atrial fibrillation, and to treat high blood pressure.
What are beta blockers?
You can identify beta blockers by their generic names—they all end in “lol.” Common examples include
- atenolol (Tenormin)
- bisoprolol
- carvedilol (Coreg)
- metoprolol (Lopressor, Toprol)
- nadolol
- propranolol (Inderal, InnoPran).
How do beta blockers work in the body?
Beta blockers work by blocking beta receptors, which are tiny proteins on the outer surfaces of cells throughout the body – especially in the heart, blood vessel walls, lungs, kidneys and brain. Stress hormones (namely epinephrine and norepinephrine) stimulate beta receptors and trigger effects that vary depending on the organ. In the heart and blood vessels, adrenaline and norepinephrine speed up the heart, strengthen the contractions of the heart and tighten the blood vessel walls.
Beta blockers undermine these effects by attaching to beta receptors and preventing the stress hormones from binding to them. As a result, the heart slows and blood vessels relax, actions that lower blood pressure and reduce the heart’s workload.
Common side effects of beta blockers
The side effects of beta blockers are usually not life-threatening. But because beta receptors are found in so many different tissues, these drugs can have unwanted effects throughout the body, such as
- drowsiness or tiredness
- dizziness or vertigo
- cold hands and feet
- constipation
- erectile dysfunction.
Less common side effects include allergic reactions (such as rash and swelling of the face) and difficulty sleeping. Talk to your doctor if you have side effects from a beta blocker.
Beta blockers after a heart attack
A recent study investigated the importance of beta-blockers in more than 8,500 heart attack survivors with normal or mildly reduced heart function. Half were randomly assigned to start taking a beta-blocker within two weeks of leaving the hospital; the others did not take beta blockers. Over the following four years, the researchers found no difference in repeat heart attacks, hospitalizations for heart failure, or death from any cause between the two groups. Published August 30, 2025, i New England Journal of Medicinethe results apply to subjects with cardiac function that is normal or only slightly reduced, defined as an ejection fraction of 40% or more. The ejection fraction refers to the percentage of blood that the heart sends out to the rest of the body each time it contracts. An exhaust fraction of 50% to 70% is considered normal.
Who should – and should not – take beta blockers?
If you’ve had a heart attack and have what’s called a reduced ejection fraction (an ejection fraction below 40%), a beta blocker still makes sense. People with slightly reduced ejection fraction (40% to 49%) are also likely to benefit from beta blockers. However, if you have a preserved ejection fraction (40% or higher), a beta blocker may not be necessary. What if you have a preserved ejection fraction and are already on a beta blocker? “It may be reasonable to stop taking it a year after your heart attack, provided you don’t need the drug for another reason,” says Dr. McCarthy.
Beta blockers are generally less effective than other blood pressure medications in preventing cardiovascular problems, especially stroke. “However, even if beta blockers are not a first choice, they can still be a useful addition if your blood pressure remains uncontrolled while on other drugs,” says Dr. McCarthy.
Beta blockers are also used to prevent migraine attacks and reduce hand tremors. They can reduce common symptoms of anxiety such as sweating, rapid heartbeat and flushing. Beta-blocker eye drops are routinely prescribed to lower eye pressure in people with glaucoma. If you are currently taking a beta blocker for any reason, do not stop taking it until you have spoken to your doctor.
This article appears in the January 2026 issue of Harvard Heart Letter under the title “New thinking about beta-blocker use.”
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