Atenolol, Oral Tablet

Medically reviewed by University of Illinois-Chicago, Drug Information Group on April 5, 2017Written by University of Illinois-Chicago, Drug Information Group

Important warnings

FDA warning: Don’t stop this drug suddenly

  • This drug has black box warnings. These are the most serious warnings from the Food and Drug Administration (FDA). Black box warnings alert doctors and patients about drug effects that may be dangerous.
  • Don’t stop taking atenolol suddenly. If you do, you may experience worse chest pain, a jump in blood pressure, or even have a heart attack. Stopping atenolol is not recommended. If you need to stop taking the drug, first talk to your doctor. Your dosage should be gradually decreased under your doctor's supervision.

Other warnings

  • Asthma/chronic obstructive pulmonary disease (COPD) warning: At higher doses, atenolol can make asthma or COPD worse. It does this by blocking different types of beta receptors found in breathing passages. Blocking these receptors can lead to narrowing of breathing passages, which can worsen these conditions.
  • Diabetes warning: Atenolol may mask important signs of low blood sugar, including shaking and increased heart rate. Without these signals, it becomes more difficult to recognize dangerously low blood sugar levels.
  • Poor circulation warning: If you have poor circulation in your feet and hands, you may have worse symptoms when taking atenolol. Atenolol reduces blood pressure, so you might not get as much blood to your hands and feet.

What is atenolol?

Atenolol is a prescription drug. It comes as a tablet you take by mouth. It also comes in an intravenous (IV) form, which is only given by a healthcare provider.

Atenolol is available as the brand-name drug Tenormin. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in every strength or form as the brand-name drug.

Why it's used

Atenolol is used to:

  • decrease hypertension (high blood pressure)
  • reduce angina (chest pain)
  • after a heart attack, reduce the amount of work your heart muscle has to do to push blood through your body

How it works

Atenolol belongs to a class of drugs called beta blockers. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Beta receptors are found on cells in the heart. When adrenaline activates a beta receptor, blood pressure and heart rate go up. Beta blockers prevent adrenaline from affecting beta receptors in your blood vessels and heart. This causes blood vessels to relax. By relaxing the vessels, beta blockers help to lower blood pressure and reduce chest pain. They also help to decrease the heart's demand for oxygen.

Beta blockers don’t permanently change blood pressure and chest pain. Instead, they help to manage the symptoms.

Atenolol side effects

Atenolol may cause drowsiness. It can also cause other side effects.

More common side effects

The more common side effects of atenolol can include:

  • cold hands and feet
  • constipation
  • diarrhea
  • dizziness
  • headache
  • reduced sex drive or impotence
  • shortness of breath
  • unexplained tiredness
  • leg pain
  • blood pressure that’s lower than usual

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Allergic reaction. Symptoms can include:
    • a large, red rash; swelling of the hands, feet, a large, red rash
    • fever
    • swelling of the hands, feet, and ankles
    • swelling of your throat or tongue
    • trouble breathing
  • Depression. Symptoms can include:
    • feelings of sadness or hopelessness
    • anxiety
    • tiredness
    • trouble focusing
  • Unusual weight gain. Symptoms can include:
    • swelling of the feet, ankles, or arms

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we can not guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.

Atenolol may interact with other medications

Atenolol oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Examples of drugs that can cause interactions with atenolol are listed below.

Mental health drugs

Reserpine and monamine oxidase inhibitors (MAOIs) may increase or add to the effects of atenolol. They may also increase lightheadedness or slow your heart rate more.

MAOIs can continue to interact with atenolol for up to 14 days after taking them. Examples of MAOIs include:

  • isocarboxazid
  • phenelzine
  • selegiline
  • tranylcypromine

Heart rhythm drugs

Taking certain heart drugs with atenolol can slow down your heart rate too much. Examples of these drugs include:

  • digitalis
  • amiodarone
  • disopyramide

Calcium channel blockers

Like atenolol, these drugs are used to treat high blood pressure and several other heart problems. If combined with atenolol, they may reduce the contractions of your heart and slow it down more. Doctors sometimes use this combination under close supervision. Examples of these drugs include:

  • amlodipine
  • diltiazem
  • felodipine
  • celvidipine
  • flunaraizine
  • isradipine
  • nicardipine
  • nifedipine
  • nimodipine
  • nisoldipine
  • verapamil

Alpha blockers

Alpha blockers lower blood pressure. They may decrease blood pressure too much when combined with atenolol. Examples of these drugs include:

  • guanethidine
  • betanidine
  • reserpine
  • alpha-methyldopa
  • prazosin
  • clonidine

Clonidine must be carefully managed if it's combined with atenolol. Suddenly stopping the drug while also taking atenolol can cause a big jump in blood pressure.

Pain drug

Taking indomethacin with atenolol can reduce the blood pressure-lowering effects of atenolol.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we can not guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

Atenolol warnings

This drug comes with several warnings.

Allergy warning

Atenolol can cause a severe allergic reaction. Symptoms can include:

  • a large, red rash
  • fever
  • swelling of the hands, feet, and ankles
  • swelling of your throat or tongue
  • trouble breathing

If you develop these symptoms, call 911 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

Warnings for people with certain health conditions

For people with asthma/chronic obstructive pulmonary disease (COPD): Generally, people with asthma or COPD shouldn’t take atenolol. A doctor may still prescribe it, but only in small doses with careful monitoring. Atenolol works to block beta receptors on cells in the heart. But at higher doses, atenolol can block different types of beta receptors found in breathing passages. Blocking these receptors can lead to narrowing of breathing passages, making asthma or COPD worse.

For people with diabetes: Atenolol may mask important signs of low blood sugar, including shaking and increased heart rate. Without these signals, it becomes more difficult to recognize dangerously low blood sugar levels.

For people with poor circulation: If you have poor circulation in your feet and hands, you may have worse symptoms when taking atenolol. Atenolol reduces blood pressure, so you might not get as much blood to your hands and feet.

Warnings for other groups

For pregnant women: Atenolol is a category D pregnancy drug. That means two things:

  1. Studies show a risk of adverse effects to the fetus when the mother takes the drug.
  2. The benefits of taking atenolol during pregnancy may outweigh the potential risks in certain cases.

Atenolol use in the second trimester of pregnancy has been associated with birth of babies who are smaller than normal. Also, newborns of mothers who took atenolol at the time of birth may be at risk of hypoglycemia (lower than normal blood sugar levels) and bradycardia (slower than normal heartbeat).

If you take atenolol and are considering having a baby, or if you are pregnant, talk to your doctor right away. Atenolol is not the only medication that treats high blood pressure. Other drugs have fewer adverse effects during pregnancy and breastfeeding. Your doctor will be able to tell you if a different drug or a dose adjustment is an option for you.

If you become pregnant while taking this drug, call your doctor right away.

For women who are breastfeeding: Atenolol is absorbed into breast milk and could be passed to a child who is breastfed. Newborns who breastfeed from mothers who take atenolol are also at risk of hypoglycemia and bradycardia.

However, infants who are older than 3 months seem to be at little risk of the effects of atenolol in breast milk. Talk to your doctor before breastfeeding while taking this drug.

Q:

Can grapefruit affect how atenolol works?

A:

Grapefruit does not directly affect how atenolol works. However, taking atenolol with food in your stomach can slow down the absorption of the drug. This means that the drug moves more slowly from your digestive tract into your bloodstream. If your body absorbs the drug more slowly, more of it leaves your body as waste than enters your blood. You have to have enough of the drug in your blood for it to work right. You can help this drug work better by taking it on an empty stomach at the same time every day. Take it either a half hour before you eat, or two hours after you eat. Taking it at bedtime, at least two hours after your last meal of the day, can help you to avoid lightheadedness from the drug.

Healthline Pharmacist Review TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

How to take atenolol

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

Drug form and strengths

Generic: Atenolol

  • Form: oral tablet
  • Strengths: 25 mg, 50 mg, 100 mg

Brand: Tenormin

  • Form: oral tablet
  • Strengths0: 25 mg, 50 mg, 100 mg

Dosage for high blood pressure

Adult dosage (ages 18–64 years)

Atenolol is often started at 50 mg once a day. It’s gradually adjusted if needed.

Child dosage (ages 0–17 years)

This medication has not been studied in children. It should not be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dosage may cause levels of the drug to be higher than normal in your body. If you’re a senior, you may need a lower dosage or you may need a different dosing schedule.

Dosage for angina (chest pain)

Adult dosage (ages 18–64 years)

Atenolol is often started at 50 mg once a day. It’s gradually adjusted if needed.

Child dosage (ages 0–17 years)

This medication has not been studied in children. It should not be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dosage may cause levels of the drug to be higher than normal in your body. If you’re a senior, you may need a lower dosage or you may need a different dosing schedule.

Dosage after a heart attack

Adult dosage (ages 18–64 years)

After heart attack, the dosage is highly individual. It depends on the cause and the effects of the heart attack. Your doctor will monitor your blood pressure and how your heart is responding and may adjust your dosage. This drug is often started in the hospital.

Atenolol is often dosed at 100 mg per day, given once a day or in two divided doses. The dosage is gradually adjusted if needed.

Child dosage (ages 0–17 years)

This medication has not been studied in children. It should not be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dosage may cause levels of the drug to be higher than normal in your body. If you’re a senior, you may need a lower dosage or you may need a different dosing schedule.

Special dosage considerations

For seniors: Seniors may need a smaller dosage of atenolol at first because they can be more sensitive to the way medications act in their body. Also, as people age, they sometimes have a harder time clearing drugs from their body. After a low initial dosage, their dosage may then increase gradually.

For people with kidney disease: Kidney disease can make it more difficult for you to clear this drug from your body. Having kidney disease may affect your dosage. Talk to your doctor about the best dosage for you.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we can not guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.

Take as directed

Atenolol oral tablet is used for long-term treatment. It comes with serious risks if you don’t take it as prescribed.

If you don’t take It: If you have high blood pressure or chest pain and don’t take your atenolol, you risk: increasing your blood pressure, damaging your blood vessels or main organs, such as your lungs, heart, or liver, and increasing your risk of a heart attack.

If you stop taking it suddenly: If you suddenly stop taking atenolol for high blood pressure, chest pain, or after a heart attack, you raise your risk of heart attack.

If you don’t take it on schedule: Not taking atenolol every day, skipping days, or taking doses at different times of day also come with risks. Your blood pressure might fluctuate too often. That might increase your risk for a heart attack.

If you miss a dose: If you miss a dose, just take the next dose as planned. Don’t double your dose.

How to tell if the drug is working: You can tell that atenolol is working if it lowers your blood pressure. If you’re taking it for angina, you can tell it’s working if it reduces your chest pain.

Important considerations for taking atenolol

Keep these considerations in mind if your doctor prescribes atenolol for you.

General

You can cut or crush the tablet.

Storage

  • Store this drug at room temperature between 68°F and 77°F (20°C and 25°C).
  • Keep the medication tightly closed and in a light-resistant container. Store it away from moisture.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Self-monitoring

Because atenolol can lower blood pressure, your doctor may ask that you periodically check your blood pressure while taking it. Let your doctor know if you experience blood pressure readings that are either too high or too low while taking atenolol.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t harm your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

Disclaimer: Healthline 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 other healthcare professional before taking any medication. The drug information contained here in 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.

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