Atenolol: 6 things you should know
Medically reviewed by C. Fookes, BPharm. Last updated on Sep 14, 2018.
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.
- 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.
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.
- 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.
Atenolol [Package Insert]. Revised 09/2018. Drugs.com https://www.drugs.com/ppa/atenolol.html
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.
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- Drug class: cardioselective beta blockers
Other brands: Tenormin