If you have high blood pressure or coronary artery disease, your doctor may have prescribed a beta-blocker. These drugs block the effects of stress hormones, such as epinephrine (adrenaline) and norepinephrine, on the heart and arteries. As a result, your heart rate slows…your heart beats with less force…and your blood pressure gets lower.
Problem: Beta-blockers, also called beta-adrenergic blocking agents, are linked to a range of commonly known side effects—fatigue, weight gain and more. But some types of beta-blockers can cause other more significant problems that most patients—and even their doctors—are not aware of. Even worse: Many people taking these drugs don’t actually need to be taking them at all.
Bottom Line Personal asked hypertension specialist Samuel J. Mann, MD, about the side effects of beta-blockers and how to determine if you are taking the right one—or if you even need one…
THE TRUTH ABOUT BETA-BLOCKERS
Beta-blockers can be roughly categorized into two types…
Lipophilic (lipid-soluble), including the most widely prescribed beta-blockers— metoprolol (Toprol) and carvedilol (Coreg)—as well as propranolol (Inderal).
Hydrophilic (water-soluble), including bisoprolol (Zebeta), nadolol (Corgard), atenolol (Tenormin) and betaxolol (Kerlone).
Problem: The blood level achieved by a dose of a lipophilic beta-blocker differs greatly from patient to patient depending on how fast or slow the liver metabolizes the drug. A “rapid metabolizer” will end up with a very low, and therefore ineffective, blood level. A “slow metabolizer” will end up with a very high blood level and likely will suffer more side effects.
There’s no easy test to determine whether you are a fast or a slow metabolizer, but the difference in blood levels can be tremendous—slow metabolizers may have 10 to 20 times higher levels of the drug in their bloodstream than fast metabolizers who are taking the same dosage. And the amount of the medication that reaches the bloodstream will determine whether or not you will suffer the following side effects and how severely.
Fatigue. Many people taking betablockers— either lipophilic or hydrophilic— who feel less energetic assume that they’re experiencing age-related fatigue. But there is a direct connection between beta-blockers and fatigue— both types of beta-blockers reduce heart rate and cardiac output, so the heart doesn’t pump as much as it would without the medication, causing the person to feel tired.
Weight gain. Research shows that many people taking beta-blockers gain a few pounds, but a small percentage gain a significant amount of weight, likely related to the reduced energy caused by the beta-blocker.
Other side effects include cold fingers and/or toes, erectile dysfunction and thinning hair.
WHAT YOUR DOCTOR MAY NOT KNOW
Unlike hydrophilic beta-blockers, lipophilic beta-blockers penetrate the blood-brain barrier and enter brain tissue, and that can cause the following more troubling side effects…
Mental dullness. In addition to fatigue, lipophilic beta-blockers can cause subtle or not-so-subtle mental dullness or, as some patients describe it, “brain fog.” This side effect impacts perhaps 10% to 20% of patients and might be more pronounced in those who have preexisting cognitive impairment. Many patients taking beta-blockers tolerate these side effects for years without suspecting that their medication is the cause.
Depression. Doctors have long suspected a link between beta-blockers and depression, but research now indicates that the medication itself does not seem to be the direct cause.
New finding: In a 2021 meta-analysis published in the American Heart Association journal Hypertension, researchers examined data from more than 50,000 individuals collected in 258 studies involving beta-blockers. They found that while depression was the most frequently reported mental health side effect, it did not happen more often during treatment with beta-blockers than during treatment with a placebo. Exception: Propranolol specifically has been linked to increased risk for depression and nightmares.
A BETTER APPROACH
No one should have to tolerate these side effects. Fortunately, there are effective and readily available alternatives. In many cases, the patient’s condition can be treated without a beta-blocker or with one that is less likely to cause these side effects. Steps to take…
Ask your doctor about alternative treatments for your condition. When treating hypertension, many physicians are quick to write prescriptions for beta-blockers, but in most situations, other drugs—ACE inhibitors, angiotensin receptor antagonists (ARBs), calcium channel blockers or diuretics—are more appropriate and usually cause fewer side effects.
Exception: Hypertension driven by the sympathetic nervous system is better treated with a beta-blocker. This type of high blood pressure often has a mind-body component and may be accompanied by anxiety and/or rapid heart rate. Your doctor may want you to take both a beta-blocker and an alpha-blocker. Like beta-blockers, alpha-blockers block the effects of stress hormones on the body, but they also cause the blood vessels to dilate (vasodilate), which can mitigate the cold hands and feet that beta-blockers sometimes cause. The most widely prescribed alpha-blocker is doxazosin (Cardura). This combination is highly effective and underutilized. A new beta-blocker, nebivolol (Bystolic), also has vasodilating effects.
Caution: A newer beta-blocker, carvedilol (Coreg), includes an alphablocker, but it is lipophilic and so crosses into the brain, where it can cause the associated side effects.
If you must continue to take a beta-blocker, ask your doctor if you can switch to a hydrophilic betablocker, which doesn’t cross the bloodbrain barrier. Examples: Bisoprolol (Zebeta), nadolol (Corgard), atenolol (Tenormin) and betaxalol (Kerlone). Blood levels of these beta-blockers are more predictable, and the side effects are fewer.
You also can inquire about taking a lower dose. Example: Bisoprolol comes in a standard five-milligram pill, but half a pill often is sufficient to treat high blood pressure.
If you have had cardiac bypass surgery, angioplasty or stenting, ask your doctor how long you have to continue taking a beta-blocker after the procedure. There is no clear evidence that beta-blockers need to be continued beyond the first year in patients who have undergone these procedures. Yet many of these patients continue taking a beta-blocker indefinitely.