Atenolol belongs to a class of medications called beta-blockers. It is used to lower high blood pressure and to prevent the symptoms of angina (chest pain). It works by reducing the demands put on the heart.

Atenolol comes as a tablet to take by mouth. It is usually taken once or twice a day. To help you remember to take atenolol, take it around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take atenolol exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Atenolol controls high blood pressure and angina but does not cure them. It may take 1-2 weeks before you feel the full benefit of atenolol. Continue to take atenolol even if you feel well. Do not stop taking atenolol without talking to your doctor.

Atenolol may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

dizziness
lightheadedness
tiredness
drowsiness
depression
upset stomach
diarrhea
Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, call your doctor immediately:

shortness of breath
swelling of the hands, feet, ankles, or lower legs
unusual weight gain
fainting
Atenolol may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If your doctor prescribes a low-salt or low-sodium diet, follow these directions carefully.

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include:

lack of energy
difficulty breathing
wheezing
slow heartbeat
fainting
swelling of the hands, feet, ankles, or lower legs
unusual weight gain
shakiness
dizziness
rapid heartbeat
sweating or confusion
blurred vision
headache
numbness or tingling of the mouth
weakness
excessive tiredness
pale color
sudden hunger

Keep all appointments with your doctor. Your blood pressure should be checked regularly to determine your response to atenolol. Your doctor may ask you to check your pulse (heart rate). Ask your pharmacist or doctor to teach you how to take your pulse. If your pulse is faster or slower than it should be, call your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Atenolol is used alone or in combination with other medications to treat high blood pressure. It also is used to prevent angina (chest pain) and treat heart attacks. Atenolol is in a class of medications called beta blockers. It works by slowing the heart rate and relaxing the blood vessels so the heart does not have to pump as hard.

Atenolol is also used sometimes to prevent migraine headaches and to treat alcohol withdrawal, heart failure, and irregular heartbeat. Talk to your doctor about the possible risks of using this medication for your condition. This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication

Before taking atenolol,

tell your doctor and pharmacist if you are allergic to atenolol or any other medications.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the following: calcium channel blockers such as diltiazem (Cardizem, Dilacor, Tiazac, others) and verapamil (Calan, Isoptin, Verelan); clonidine (Catapres); nonsteroidal anti-inflammatory medications (NSAIDs) such as indomethacin (Indocin); and reserpine (Serpalan, Serpasil, Serpatabs). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have or have ever had asthma or other lung disease; diabetes; severe allergies; an overactive thyroid gland (hyperthyroidism); pheochromocytoma; heart failure; a slow heart rate; circulation problems; or heart or kidney disease.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking atenolol, call your doctor immediately.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking atenolol.
you should know that if you have allergic reactions to different substances, your reactions may be worse while you are using atenolol, and your allergic reactions may not respond to the usual doses of injectable epinephrine. IMPORTANT WARNING:Do not stop taking atenolol without talking to your doctor. Suddenly stopping atenolol may cause chest pain, heart attack, or irregular heartbeat. Your doctor will probably decrease your dose gradually.