Common and Rare Beta Blocker Side Effects to Be Aware Of - GoodRx (2024)

Beta blockers are commonly used to treat heart-related problems. This includes conditions like high blood pressure, heart failure, and arrhythmias (irregular heartbeats). As their name implies, they work by blocking beta receptors (chemical binding sites) in the body. This causes the heart to beat slower and with less force. It also helps lower blood pressure.

Common beta blockers include atenolol (Tenormin), carvedilol (Coreg), and metoprolol (Lopressor, Toprol XL). They’re generally well-tolerated by most people. But as with all medications, they do have side effects you should know about.

Beta blocker side effects overview

Below are the common and rare beta blocker side effects reported in clinical studies. Keep in mind that individual beta blockers may have different side effects than listed below. So be sure to discuss the side effects of your medication with your healthcare team so you know what to expect.

Common or mild beta blocker side effects include:

• Low blood pressure

• Slow heart rate

• Fatigue

• Dizziness

• Nausea

• Constipation

• Erectile dysfunction

• Decreased sex drive

• Insomnia

• Nightmares or vivid dreams

• Weight gain

Rare but serious beta blocker side effects include:

• Heart block

• Trouble breathing

• Masking the effects of low blood glucose (sugar)

• Allergic reactions

Beta blockers also have a boxed warning for stopping a beta blocker abruptly. A boxed warning is the FDA’s strictest warning for medications.

While rare, this side effect can be life-threatening. Stopping a beta blocker abruptly may lead to a dangerous increase in blood pressure and heart rate. This can lead to serious complications, such as a heart attack or even death.

Let’s take a look at 11 beta blocker side effects in more detail, including what to do if they occur.

1. Slow heart rate

Beta blockers can cause your heart to pump with less force, which can lead to bradycardia (slow heart rate). Your heart rate is usually considered too low when it beats less than 60 times per minute while you’re at rest.

This side effect may not always be noticeable. But sometimes you may feel lightheaded, tired, or out of breath. You may also have trouble exercising or walking up a flight of stairs.

If you start to experience these symptoms or notice that your heart rate seems slower than usual, let your prescriber know.

2. Low blood pressure

Beta blockers can lower your blood pressure. Although this is a good thing when treating high blood pressure, you don’t want it to drop too low. When this happens, not enough blood flows through the body. This can lower the amount of oxygen and nutrients delivered to your brain and other organs.

Symptoms of low blood pressure include dizziness, fatigue, and feeling faint. This is more common in the first few days after you start taking a beta blocker for the first time. After that, these symptoms usually go away as your body gets used to the medication. But if they continue, contact your prescriber.

Sometimes, when you change from a sitting or laying position to a standing position too quickly your blood pressure will drop. This is called orthostatic hypotension. It can make you feel dizzy or even lose consciousness. If you’re taking beta blockers, make sure you rise slowly when standing up. Take your time to gain your balance before walking after standing. This will help you avoid falling and hurting yourself if this side effect occurs.

3. Fatigue

Beta blockers can cause you to feel weak or more tired than usual. As mentioned earlier, fatigue can also be a sign of a slow heart rate or low blood pressure.

You may want to take it easy when you first start taking beta blockers. Try to avoid strenuous activities and make sure you’re getting enough rest. It will also help you feel your best if you’re eating a healthy diet and drinking plenty of water.

Even though some side effects may subside after a few days, it may take several weeks for your body to fully adjust to a beta blocker. But if you notice increased or persistent tiredness, let your prescriber know.

4. Dizziness

You may feel dizzy or lightheaded while taking a beta blocker. This side effect often goes away after a few days of taking the medication.

You should wait to drive or perform other activities that require full mental alertness when you first start this medication until you’re sure it’s safe for you to do so.

If you continue to feel dizzy, talk to your prescriber. It could be a sign that your blood pressure is too low. So they may need to adjust your dosage or switch your medication to manage it.

5. Nausea

Beta blockers can cause nausea in some people. You can help relieve nausea by taking your medication with food. It may also help to avoid spicy or fried food. If you have severe nausea, talk to your prescriber about it. They may decide a beta blocker isn’t the right choice for you.

6. Constipation

Constipation is another common side effect of beta blockers. Drinking plenty of water, eating a high fiber diet, and exercising regularly will usually help with this. But if that’s not helping, you can also try over-the-counter medications, such as docusate (Colace) or polyethylene glycol (Miralax).

If your constipation does not improve within 7 days of taking these medications, be sure to let your prescriber know. They’ll want to make sure there isn’t something more serious going on.

7. Sleep disturbances

Some people taking beta blockers can experience insomnia (trouble sleeping) or nightmares. A study suggests that beta blockers lower the amount of melatonin that’s released in the body. Melatonin helps to regulate your sleep cycle. So low levels of it may make it harder for you to sleep well. And some beta blockers, such as bisoprolol and atenolol, seem to have a lower risk of this side effect than others.

To help with this, try relaxing activities — like taking a warm bath or journaling — before going to bed. Avoid watching TV or looking at your phone right before bedtime. These activities may be too stimulating.

You can also discuss medication options for sleep with your pharmacist or prescriber if other methods aren’t working.

8. Sexual side effects

Beta blockers may cause erectile dysfunction (ED) or a lower sex drive in some people. This may resolve on its own as your body adjusts to the medication. But if it’s a problem for you, don’t be embarrassed to talk to your prescriber about it. In many cases, they may be able to change your medication or prescribe an ED treatment to help.

Good to know: Nebivolol (Bystolic) is a beta blocker that doesn’t seem to cause sexual side effects. That’s because it works slightly differently than other beta blockers. Talk to your prescriber about whether it’s an option for you if you’re concerned about sexual side effects from your medication.

9. Masking symptoms of low blood glucose

Beta blockers can hide some symptoms of low blood glucose (hypoglycemia), such as shaking, confusion, and irritability. This is especially dangerous if you have diabetes. It can prevent you from recognizing and treating low blood sugar soon enough. Untreated hypoglycemia can lead to seizures, coma — and even death.

Sweating is one symptom of hypoglycemia that isn’t masked by beta blockers. So if you have diabetes and are taking a beta blocker, check your blood glucose if you start to feel sweaty or clammy. You should always have treatment options on hand (such as glucose tablets or juice) to help bring your blood glucose level back up.

10. Heart block

Although rare, all beta blockers have the potential to cause or worsen heart block. Your heart has an electrical system that helps it pump properly. Beta blockers can sometimes “block” this system, which can make your heart slow down or even stop entirely. Heart block is life-threatening. Symptoms include:

• Dizziness

• Fainting

• Chest pain

• Feeling your heart skip a beat or beat in an unusual way

• Shortness of breath

If you’re taking a beta blocker and you’re at high risk for heart problems, your prescriber will probably want to check in with you regularly. This helps them make sure everything is working properly and catch any issues before severe side effects such as heart block happen. But if you experience these symptoms, seek medical care right away.

11. Trouble breathing

Some beta blockers can tighten the muscles lining the airways of your lungs. This can make it harder for you to breathe. People who have asthma are at higher risk for this side effect.

If you have asthma and need to take a beta blocker, certain types may be safer for you. These are called “cardio-selective” beta blockers. They don’t affect the receptors in your airways as much as non-selective beta blockers do. Some examples of cardio-selective beta blockers are atenolol, bisoprolol, and metoprolol.

Before starting a beta blocker, let your prescriber know if you have a history of asthma or other lung conditions.