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Atenolol (“ah TEN oh lol”)

The beta-blocker atenolol can be helpful for treating rapid heart rhythms. It is sometimes prescribed for hypertension.


Atenolol (Tenormin) is known as a beta-blocker. That means the drug works in part by blunting the action of adrenaline, the body’s natural fight-or-flight chemical. People normally respond to stressful situations with a rapid pulse, a pounding heart and an increase in blood pressure. Atenolol helps block such reactions. This medicine is normally prescribed for high blood pressure, chest pain, or heart attacks.

Although the FDA has not specifically approved its use for other purposes, doctors sometimes prescribe atenolol (Tenormin) to treat irregular heart rhythms, performance anxiety such as stage fright, and to prevent migraine headaches.

People’s Pharmacy Perspective

We suspect that one of the reasons beta-blockers are so popular with insurance companies and HMOs is that they are inexpensive. These drugs have been around a long time and generally have low cost generics available. Current research (1,2) however, suggest that due to their lack of efficacy, beta-blockers such as atenolol (Tenormin) should rarely be the first line of treatment for high blood pressure.

Experts also cast serious doubts about their effectiveness in the prevention of initial heart attacks and strokes for hypertensive patients and have concerns about the multiple side effects beta-blockers could cause (3,4). Beta-blockers are valuable for managing chest pain and especially preventing another heart attack after someone has already had one. Finally, they may also be valuable when adequate control is not achieved with other classes of drugs, but you and your physician will need to decide if the benefits outweigh the risks.

Be certain to consult a physician about your health, especially with regard to any signs or symptoms that may require diagnosis or medical attention. Information provided is not a substitute for the medical advice or care of a physician or other health care professional.

Special Precautions

Do not stop taking atenolol (Tenormin) suddenly without first talking to your doctor. Stopping abruptly may trigger serious and potentially fatal heart problems.

This medication is not recommended for some people: People who have had an allergic reaction to beta-blockers, atenolol (Tenormin), or its components; people with certain heart problems, abnormal heart rhythms or heart failure, since the medicine could occasionally lead to serious cardiac complications.

Some people must be very carefully monitored if they take beta-blockers such as atenolol (Tenormin): Asthmatics and patients with other respiratory problems are especially vulnerable as these drugs can make breathing worse. Atenolol (Tenormin) is a little better than other beta-blockers in this regard, but monitor your breathing carefully.

Diabetics should inform their physicians if being prescribed atenolol (Tenormin) as the medication may mask the signs of low blood sugar levels. People with a history of depression should inform their doctors to ensure both their depression and beta-blocker therapy is well managed.

While atenolol (Tenormin) is less likely to affect the nervous system than others in its class, beta-blockers have been known to contribute to depression. People with a thyroid disorder should also be carefully monitored as this medication may mask signs of an overly active thyroid. People with kidney impairments or who are elderly may need their atenolol (Tenormin) dose adjusted.

More people who must also be very carefully monitored if they take beta-blockers: Women who plan to become pregnant or breastfeed should not take this medication unless their doctors determine it is appropriate. Atenolol may cause harm to an unborn baby.

Be certain to inform your doctor of any other condition you have, as it may affect whether you should take atenolol (Tenormin), your dose, or require you to take special tests during treatment.

Taking the Medicine

Atenolol (Tenormin) should be taken with a full glass of water and can be taken at meal time or on an empty stomach. If you find this medicine causes digestive tract upset, it may be better tolerated when taken with food.

Atenolol (Tenormin) should not be taken together with orange juice as it may reduce the medication’s effect. (5) Avoid drinking alcohol, which could increase your symptoms of drowsiness and dizziness while you are taking atenolol (Tenormin). Don’t take calcium supplements or antacids at the same time as atenolol (Tenormin), as they may reduce its absorption.

You may need to temporarily stop taking atenolol (Tenormin) if you will be undergoing surgery since anesthesia may interact with atenolol (Tenormin) and affect how your heart functions. Be sure to let the surgeon and/or anesthesiologist know well in advance of surgery that you are taking atenolol (Tenormin). Never stop taking atenolol (Tenormin) suddenly. Your doctor must reduce your dose gradually to prevent serious heart problems.

Common Side Effects of Atenolol (Tenormin)

This medication can cause a number of side effects. They include a slower heart rate, sexual difficulties, sleep problems, tiredness, anxiety, and nervousness.

This medicine may also have a negative effect on cholesterol and other blood fats, so a lipid test before treatment and periodically thereafter would be prudent.

Although Atenolol (Tenormin) is a little less likely to affect the nervous system than certain other drugs in this class, be alert for the beta-blocker blahs. Symptoms of psychological depression, fatigue, decreased concentration, memory loss and mood swings may come on slowly and insidiously.

Serious Side Effects of Atenolol (Tenormin)

Obtain emergency medical care if you experience these signs of a potential allergic reaction: breathing difficulties, hives, or swelling in your face, lips, tongue, or throat. Call your doctor promptly if you experience any of these serious side effects:

  • wheezing, worsening asthma;
  • slow or uneven heartbeats;
  • feeling light-headed, fainting;
  • feeling short of breath, even with mild exertion;
  • swelling of your ankles or feet;
  • nausea, stomach pain, fever, loss of appetite, dark urine, pale stools, yellowing of the skin or eyes;
  • depression; or
  • cold feeling in your hands and feet.

There may be other side effects not listed here. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

Drug Interactions with Atenolol (Tenormin)

This drug can interact with a number of other compounds, including the blood pressure medicine clonidine (Catapres). This drug should never be suddenly discontinued by a person on atenolol (Tenormin) or any other beta-blocker, as the sudden increase in blood pressure could be life-threatening.

Calcium channel blockers (verapamil, diltiazem), which are also heart/blood pressure medications, could have increased effects if given together with atenolol. Taking atenolol with calcium channel blockers is generally not advised as the combined effects might lead to serious heart problems. If they must be taken together, the dose for both or one medication may need to be reduced and cardiac function should be carefully monitored.

A potentially fatal increase in blood pressure could occur when epinephrine is injected into someone taking a beta-blocker such as atenolol. Epinephrine is often included with a local anesthetic injected for dental work or minor surgery, or may be given if someone has a serious allergic reaction that closes airways.

Many other drugs interact with atenolol, including ampicillin and medicines used to treat anxiety, asthma, blood pressure and heart problems. Arthritis medicine and aspirin may reduce the effectiveness of some beta-blockers. Drugs used to treat migraines, tuberculosis and high cholesterol do not mix well with beta-blockers.

There may be other drugs that interact with atenolol not listed here. Do not start any new medications or make changes to your treatment without first consulting your doctor.


  1. Lindholm, L. H., et al. “Should Beta-Blockers Remain First Choice in the Treatment of Primary Hypertension? A Meta-Analysis.” Lancet 2005;366:1545-1553.
  2. Kaplan, N.M., and Opie, L.H. “Controversies in Hypertension.” Lancet 2006;367:168-176.
  3. Beevers, D.G. “the End of Beta-Blockers for Uncomplicated Hypertension?” Lancet 2005;366:1510-1512.
  4. Carlberg, B., et al. “Atenolol in Hypertension: Is It a Wise Choice?” Lancet 2004;364:1684-1689.
  5. Lilja JJ, et al. European Journal of Clinical Pharmacology. 2005;61:337.


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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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