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Drugs reference index «Atenolol»


Brand names: Tenormin

Why is Atenolol prescribed?

Tenormin, a type of medication known as a beta blocker, is used in the treatment of high blood pressure, angina pectoris (chest pain, usually caused by lack of oxygen in the heart muscle due to clogged arteries), and heart attack. When used for high blood pressure it is effective alone or combined with other high blood pressure medications, particularly with a thiazide-type water pill (diuretic). Beta blockers decrease the force and rate of heart contractions.

Occasionally doctors prescribe Tenormin for treatment of alcohol withdrawal, prevention of migraine headache, and bouts of anxiety.

Most important fact about Atenolol

If you have high blood pressure, you must take Tenormin regularly for it to be effective. Since blood pressure declines gradually, it may be several weeks before you get the full benefit of Tenormin; and you must continue taking it even if you are feeling well. Tenormin does not cure high blood pressure; it merely keeps it under control.

How should you take Atenolol?

Tenormin can be taken with or without food. Take it exactly as prescribed, even if your symptoms have disappeared.

Try not to miss any doses, especially if you are taking Tenormin once a day. If Atenolol is not taken regularly, your condition may worsen.

  • If you miss a dose...Take the forgotten dose as soon as you remember. If it's within 8 hours of your next scheduled dose, skip the one you missed and go back to your regular schedule. Never take 2 doses at the same time.
  • Storage instructions...Store Tenormin at room temperature; protect from light.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Tenormin.

  • Side effects may include:Dizziness, fatigue, nausea, slow heartbeat

Why should Atenolol not be prescribed?

If you have heart failure, inadequate blood supply to the circulatory system (cardiogenic shock), heart block (conduction disorder), or a severely slow heartbeat, you should not take Atenolol. You'll also need to avoid it if it gives you an allergic reaction.

Special warnings about Atenolol

If you have a history of severe congestive heart failure, Tenormin should be used with caution.

Tenormin should not be stopped suddenly. It can cause increased chest pain and heart attack. Dosage should be gradually reduced.

If you suffer from asthma, seasonal allergies, or other bronchial conditions, coronary artery disease or kidney disease, Atenolol should be used with caution.

Ask your doctor if you should check your pulse while taking Tenormin. This medication can cause your heartbeat to become too slow.

This medication may mask the symptoms of low blood sugar or alter blood sugar levels. If you are diabetic, discuss this with your doctor.

Notify your doctor or dentist that you are taking Tenormin if you have a medical emergency, and before you have surgery or dental surgery.

Tenormin may cause harm to a developing baby when taken during pregnancy. If you are pregnant or become pregnant while taking Atenolol, inform your doctor immediately.

Possible food and drug interactions when taking Atenolol

If Tenormin is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Tenormin with the following:

Ampicillin (Omnipen, others)Calcium-containing antacids such as TumsCalcium-blocking blood pressure drugs such as Calan and CardizemCertain other blood pressure drugs such as reserpine (Diupres)Clonidine (Catapres)Epinephrine (EpiPen)Indomethacin (Indocin)InsulinOral diabetes drugs such as MicronaseQuinidine (Quinidex)

Special information if you are pregnant or breastfeeding

The use of Tenormin during pregnancy may cause harm to a developing baby. If you are pregnant, become pregnant, or plan to become pregnant, inform your doctor immediately. Tenormin appears in breast milk and could affect a nursing infant. If Atenolol is essential to your health, your doctor may advise you to discontinue breastfeeding until your treatment is finished.

Recommended dosage for Atenolol



The usual starting dose is 50 milligrams a day in 1 dose, alone or with a diuretic. Full effects should be seen in 1 to 2 weeks. Dosage may be increased to a maximum of 100 milligrams per day in one dose. Your doctor can and may use Atenolol with other high blood pressure medications.

Angina Pectoris

The usual starting dose is 50 milligrams in 1 dose a day. Full effects should be seen in 1 week. Dosage may be increased to a maximum of 100 milligrams per day. In some cases, a single dose of 200 milligrams per day may be given. Dosage will be individualized by your doctor.

Heart Attack

This medication may be used in the acute treatment of heart attack. Your doctor will determine the proper dosage.

If you have kidney problems, the doctor will start you with the lowest effective dose, usually 25 milligrams once a day up to a maximum of 50 milligrams daily.


The safety and effectiveness of Tenormin have not been established in children.


The doctor will determine the dosage for an older individual, according to his or her needs, especially in the case of reduced kidney function. The usual dosage range is 25 to 50 milligrams a day.


Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.

  • Symptoms of Tenormin overdose may include:Congestive heart failure, constricted airways, low blood pressure, low blood sugar, slow heartbeat, sluggishness, wheezing
  • Atenolol MedFacts Consumer Leaflet (Wolters Kluwer)
  • Atenolol Professional Patient Advice (Wolters Kluwer)
  • atenolol Advanced Consumer (Micromedex) - Includes Dosage Information
  • Tenormin Prescribing Information (FDA)
  • Tenormin Consumer Overview

See Also...

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