Atenolol i s 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 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 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.

Special precautions

Before 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 inject able epinephrine.
• If you are having surgery, including dental surgery, tell the doctor or dentist that you are taking atenolol.
• 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.
• tell your doctor if you have or have ever had asthma or other lung disease; circulation problems; a slow heart rate; heart failure; pheochromocytoma; an overactive thyroid gland (hyperthyroidism); severe allergies; diabetes; or heart or kidney disease.
• Tell your doctor and pharmacist if you are taking drugs, nutritional supplements, vitamins, and herbal products you are taking.
• Tell your doctor and pharmacist if you are allergic to atenolol or any other medicines.

Side effects

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

• diarrhea
• upset stomach
• depression
• drowsiness
• tiredness
• lightheadedness
• dizziness

Some side effects can be serious.

• fainting
• unusual weight gain
• swelling of the hands, ankles, feet, or lower legs
• shortness of breath

Atenolol may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Symptoms of overdose may include:

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

Do not stop taking atenolol without talking to your doctor. Suddenly stopping atenolol may cause chest pain, heart attack, or irregular heartbeat.