Tenormin (atenolol) is a brand-name oral tablet that’s prescribed for high blood pressure, angina, and heart attack in adults. As with other drugs, Tenormin can cause side effects, such as tiredness and dizziness.

Tenormin has a boxed warning about the risk of serious heart problems if Tenormin is suddenly stopped. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Side effect specifics” section.

Tenormin can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Tenormin in clinical trials:

* For more information about this side effect, see “Side effect specifics.”

Mild side effects can occur with Tenormin use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Tenormin’s prescribing information.

Mild side effects that have been reported with Tenormin include:

  • tiredness
  • dizziness*
  • cold hands and feet
  • leg pain
  • diarrhea
  • nausea
  • shortness of breath
  • bradycardia (slow heart rate)*
  • hypotension (low blood pressure)
  • unusual dreams

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the FDA approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Tenormin and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics.”

Tenormin may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Tenormin’s prescribing information.

If you develop serious side effects while taking Tenormin, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

  • depression, which may include symptoms such as:
    • ongoing depressed, sad, or hopeless feelings
    • loss of interest in activities
    • trouble concentrating
    • trouble sleeping or sleeping more than usual
    • changes in appetite
  • heart problems, such as heart failure or heart block, which may include symptoms such as:
    • swelling of the lower legs and feet
    • shortness of breath
    • slow or irregular heartbeat
    • heart palpitations
  • risk of serious heart problems if Tenormin is suddenly stopped*

* For more information about this side effect, see “Side effect specifics.”

ALLERGIC REACTION

For some people, Tenormin can cause an allergic reaction. But it’s not clear whether this side effect occurred in the drug’s studies.

In general, symptoms of allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to an atenolol oral tablet, your doctor may recommend taking a different medication instead.

Learn more about some of the side effects that Tenormin may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Tenormin.

Risk of serious heart problems if Tenormin is suddenly stopped

Tenormin has a boxed warning about the risk of serious heart problems if you have coronary artery disease (CAD) and suddenly stop treatment with Tenormin. A boxed warning is the most serious warning from the FDA.

With CAD, you have hardening or narrowing of the arteries that supply blood and oxygen to your heart muscle. If you have CAD, suddenly stopping Tenormin can cause severe angina (chest pain) or even a heart attack.

Symptoms of a heart attack can include:

  • pain, pressure, squeezing or tightness in your chest
  • pain that spreads to your arm, neck, back, or jaw
  • sweating or clammy skin
  • shortness of breath
  • nausea
  • dizziness

What you can do

Due to the risk of severe angina and heart attack, you should not suddenly stop taking Tenormin. If you’re interested in stopping Tenormin treatment, be sure to talk with your doctor first. They can recommend how to safely stop taking the drug. This will usually involve slowly reducing your dosage over time.

If you have new or worsening chest pain when stopping Tenormin, talk with your doctor right away. But if you have symptoms of a heart attack, call 911 or your local emergency number right away.

If you have questions or concerns about the risk of serious heart problems when stopping Tenormin, talk with your doctor or pharmacist.

Dizziness

You may have dizziness while taking Tenormin. This side effect was commonly reported in clinical trials of the medication.

Dizziness can involve feeling dizzy, lightheaded, or faint. It can make you feel unsteady when moving around. Sometimes, dizziness can occur if you get up too quickly.

Dizziness is usually mild and typically gets better in a few days or weeks as your body adjusts to the medication. Note that dizziness and fainting can sometimes be a symptom of bradycardia (slow heart rate). For more information, see just below.

What you can do

If you feel dizzy or lightheaded while taking Tenormin, sit or lie down until the feeling goes away. Do not drive or do other potentially dangerous activities. It’s also best to avoid drinking alcohol, as alcohol is likely to make dizziness worse.

If you have dizziness that occurs upon standing up, take extra care when getting up and move slowly. For example, when getting up in the morning, sit on the edge of the bed with your feet on the floor for a few moments. Then stand up slowly while holding onto something.

If you have dizziness that’s severe, troublesome, or does not get better in a few weeks, talk with your doctor. They may adjust your dosage of Tenormin.

If you have questions or concerns about dizziness with Tenormin, talk with your doctor or pharmacist.

Bradycardia (slow heart rate)

You may have bradycardia while taking Tenormin. In clinical trials, this side effect was commonly reported in people who took Tenormin after a heart attack. It was less common in people who took Tenormin for high blood pressure.

Symptoms of bradycardia can include:

  • resting heart rate that’s slower than usual
  • feeling weak or very tired
  • dizziness or fainting
  • shortness of breath

What you can do

If you have symptoms of bradycardia while taking Tenormin, talk with your doctor. But if you’re faint or have shortness of breath, call your doctor right away.

If you have bradycardia symptoms, your doctor may want to check your heart rate. If needed, they may adjust your Tenormin dosage.

If you have questions or concerns about bradycardia with Tenormin, talk with your doctor or pharmacist.

Below is important information you should consider before taking Tenormin.

Tenormin has a boxed warning about the risk of serious heart problems if Tenormin is suddenly stopped. A boxed warning is the most serious warning from the FDA. For details, see the “Side effect specifics” section.

Other precautions

Before taking Tenormin, discuss your health history with your doctor. Tenormin may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.