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Atenolol: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm Last updated on Nov 6, 2019.

1. How it works

  • Atenolol is a medication that is used to treat certain heart conditions.
  • Atenolol works on specific receptors located in the heart (called beta1 receptors) to slow the heart rate.
  • The exact way atenolol works to lower blood pressure is not known but studies have shown it decreases cardiac output, inhibits renin release from the kidneys, and reduces the activity of the sympathetic nervous system.
  • Atenolol belongs to the class of drugs known as beta blockers. It is called a selective beta blocker because at low dosages it only works on beta1 receptors and has a low affinity for beta2 receptors located in the airways.

2. Upsides

  • Atenolol may be used in the treatment of high blood pressure (hypertension). Lowering blood pressure with medications such as atenolol has been shown to reduce the risk of a stroke or heart attack (myocardial infarction).
  • May be used long-term to manage the symptoms of angina.
  • When given to stable patients immediately following a heart attack, atenolol has been shown to reduce the risk of death.
  • Atenolol may be used alone or in addition to other antihypertensives.
  • Atenolol has a selective action on beta1 receptors located in the heart; however, this selectivity is only apparent at low dosages. At higher dosages, atenolol may affect beta2 receptors in the airways, which may affect breathing.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Slow heartbeat, dizziness, fatigue, cold extremities and heart failure are the most commonly reported side effects.
  • Generally not recommended for people with bronchospastic disease; however, may be used in certain circumstances.
  • Can mask symptoms of hypoglycemia or hyperthyroidism, so should be used with caution in people with diabetes or thyroid disease.
  • May aggravate peripheral circulatory disorders (conditions that cause reduced blood flow to the hands or feet).
  • May cause a number of unwanted heart-related effects and may affect breathing, so response must be monitored.
  • May cause changes in liver enzymes, headache, hallucinations, and impotence.
  • Cardioselectivity of atenolol is not absolute, and at dosages higher than 50mg/day atenolol is more likely to inhibit beta2 receptors, mostly located in the bronchial and vascular musculature. The lowest effective dose should be used to maintain cardioselectivity.
  • The clearance of atenolol from the body may be delayed in people with renal disease.
  • May not be suitable for some people including those with heart failure, a significantly slow heartbeat, or reduced peripheral circulation.
  • May interact with some medications including other medications used for the treatment of arrhythmias or angina.

Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.

4. Bottom Line

Atenolol works on heart-specific receptors to lower blood pressure and slow heart rate; however, this selective effect on the heart may be lost with dosages greater than 50mg/day which increases the risk that atenolol may adversely affect breathing.

5. Tips

  • May be taken with or without food.
  • Should always be used as part of a comprehensive cardiovascular risk reduction program which includes diabetes management, smoking cessation, exercise, and other drug therapies. May be used in addition to other blood pressure lowering medicines.
  • Seek medical advice immediately if shortness of breath develops.
  • Seek medical advice if any new numbness, pain, skin color changes or reduced sensitivity occurs in fingers or toes.
  • Sudden discontinuation has been associated with an exacerbation of angina, and sometimes myocardial infarction (heart attack) or ventricular arrhythmias. If you need to discontinue atenolol, your doctor will advise how to do this slowly over at least a week.
  • If you have diabetes, atenolol may mask some of the symptoms of hypoglycemia (low blood sugar).

6. Response and Effectiveness

Peak concentrations are reached within two to four hours of an oral dose of atenolol. Heart-rate and blood pressure lowering effects persist for at least 24 hours following a single dose.

7. Interactions

Medicines that interact with atenolol may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with atenolol. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with atenolol include:

  • alpha-blockers such as doxazosin or terazosin
  • indigestion and heartburn medications, such as cimetidine and ranitidine
  • insulin
  • methylphenidate
  • other medications including celecoxib, clonidine, hydralazine, and rifampicin
  • NSAIDs, such as diclofenac, ibuprofen, and indomethacin, may decrease the blood pressure-lowering capabilities of atenolol
  • some medications used to treat mental illness, such as thioridazine
  • some heart medications, such as amiodarone, clonidine, digoxin, diltiazem, propafenone, quinidine, and verapamil
  • any other medication that may also lower blood pressure, such as amitriptyline, bupropion, furosemide, or HCTZ.

People taking oral medications for diabetes may need to talk to their doctor about adjusting the dose of their medicine.

Note that this list is not all-inclusive and includes only common medications that may interact with atenolol. You should refer to the prescribing information for atenolol for a complete list of interactions.

References

Atenolol. Revised 10/2019. Drugs.com https://www.drugs.com/ppa/atenolol.html

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use atenolol only for the indication prescribed.

Copyright 1996-2019 Drugs.com. Revision date: November 6, 2019.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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