Conduction in the AV node is also prolonged. Atenolol is devoid of membrane stabilizing activity, and increasing the dose well beyond that producing beta-blockade does not further depress myocardial contractility. In controlled clinical trials, atenolol, given as a single daily oral dose, was an effective antihypertensive agent providing hour reduction of blood pressure. Atenolol has been studied in combination with thiazide-type diuretics, and the blood pressure effects of the combination are approximately additive.
Atenolol is also compatible with methyldopa, hydralazine, and prazosin, each combination resulting in a larger fall in blood pressure than with the single agents. The dose range of atenolol is narrow and increasing the dose beyond mg once daily is not associated with increased antihypertensive effect. The mechanisms of the antihypertensive effects of beta-blocking agents have not been established. Several possible mechanisms have been proposed and include: 1 competitive antagonism of catecholamines at peripheral especially cardiac adrenergic neuron sites, leading to decreased cardiac output, 2 a central effect leading to reduced sympathetic outflow to the periphery, and 3 suppression of renin activity.
The results from long-term studies have not shown any diminution of the antihypertensive efficacy of atenolol with prolonged use. By blocking the positive chronotropic and inotropic effects of catecholamines and by decreasing blood pressure, atenolol generally reduces the oxygen requirements of the heart at any given level of effort, making it useful for many patients in the long-term management of angina pectoris.
On the other hand, atenolol can increase oxygen requirements by increasing left ventricular fiber length and end diastolic pressure, particularly in patients with heart failure. Thirty-eight percent of each group were treated within 4 hours of onset of pain. The mean time from onset of pain to entry was 5. Patients in the atenolol group were to receive atenolol I. Injection 5 to 10 mg given over 5 minutes plus atenolol tablets 50 mg every 12 hours orally on the first study day the first oral dose administered about 15 minutes after the IV dose followed by either atenolol tablets mg once daily or atenolol tablets 50 mg twice daily on days The groups were similar in demographic and medical history characteristics and in electrocardiographic evidence of myocardial infarction, bundle branch block, and first degree atrioventricular block at entry.
During the treatment period days , the vascular mortality rates were 3. This absolute difference in rates, 0.
Most of the difference was attributed to mortality in days 0 to 1 atenolol - deaths; control - deaths. Despite the large size of the ISIS-1 trial, it is not possible to identify clearly subgroups of patients most likely or least likely to benefit from early treatment with atenolol. Good clinical judgment suggests, however, that patients who are dependent on sympathetic stimulation for maintenance of adequate cardiac output and blood pressure are not good candidates for beta-blockade.
Indeed, the trial protocol reflected that judgment by excluding patients with blood pressure consistently below mm Hg systolic. The overall results of the study are compatible with the possibility that patients with borderline blood pressure less than mm Hg systolic , especially if over 60 years of age, are less likely to benefit.
The mechanism through which atenolol improves survival in patients with definite or suspected acute myocardial infarction is unknown, as is the case for other beta-blockers in the postinfarction setting. Atenolol, in addition to its effects on survival, has shown other clinical benefits including reduced frequency of ventricular premature beats, reduced chest pain, and reduced enzyme elevation. The half-life is markedly longer in the elderly compared to younger subjects.
The reduction in atenolol clearance follows the general trend that the elimination of renally excreted drugs is decreased with increasing age. Atenolol tablets USP are indicated for the treatment of hypertension, to lower blood pressure.
Lowering blood pressure lowers the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes including atenolol.
Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than 1 drug to achieve blood pressure goals. Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits.
The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly. Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mmHg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit.
Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension for example, patients with diabetes or hyperlipidemia , and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal.
Some antihypertensive drugs have smaller blood pressure effects as monotherapy in black patients, and many antihypertensive drugs have additional approved indications and effects e. These considerations may guide selection of therapy. Angina Pectoris Due to Coronary Atherosclerosis: Atenolol is indicated for the long-term management of patients with angina pectoris.
Acute Myocardial Infarction: Atenolol is indicated in the management of hemodynamically stable patients with definite or suspected acute myocardial infarction to reduce cardiovascular mortality. Treatment can be initiated as soon as the patient's clinical condition allows.
In general, there is no basis for treating patients like those who were excluded from the ISIS-1 trial blood pressure less than mm Hg systolic, heart rate less than 50 bpm or have other reasons to avoid beta-blockade. As noted above, some subgroups e. Sympathetic stimulation is necessary in supporting circulatory function in congestive heart failure, and beta-blockade carries the potential hazard of further depressing myocardial contractility and precipitating more severe failure.
In patients with acute myocardial infarction, cardiac failure which is not promptly and effectively controlled by 80 mg of intravenous furosemide or equivalent therapy is a contraindication to beta-blocker treatment.
Continued depression of the myocardium with beta-blocking agents over a period of time can, in some cases, lead to cardiac failure. At the first sign or symptom of impending cardiac failure, patients should be treated appropriately according to currently recommended guidelines, and the response observed closely. Patients with coronary artery disease, who are being treated with atenolol, should be advised against abrupt discontinuation of therapy.
Severe exacerbation of angina and the occurrence of myocardial infarction and ventricular arrhythmias have been reported in angina patients following the abrupt discontinuation of therapy with beta-blockers.
The last two complications may occur with or without preceding exacerbation of the angina pectoris. As with other beta-blockers, when discontinuation of atenolol is planned, the patients should be carefully observed and advised to limit physical activity to a minimum. If the angina worsens or acute coronary insufficiency develops, it is recommended that atenolol be promptly reinstituted, at least temporarily.
Bradycardia and heart block can occur and the left ventricular end diastolic pressure can rise when beta-blockers are administered with verapamil or diltiazem. Because of its relative beta 1 selectivity, however, atenolol may be used with caution in patients with bronchospastic disease who do not respond to, or cannot tolerate, other antihypertensive treatment. Since beta 1 selectivity is not absolute, the lowest possible dose of atenolol should be used with therapy initiated at 50 mg and a beta 2 -stimulating agent bronchodilator should be made available.
If dosage must be increased, dividing the dose should be considered in order to achieve lower peak blood levels. It is not advisable to withdraw beta-adrenoreceptor blocking drugs prior to surgery in the majority of patients.
However, care should be taken when using anesthetic agents such as those which may depress the myocardium. Vagal dominance, if it occurs, may be corrected with atropine 1 to 2 mg IV.
Atenolol, like other beta-blockers, is a competitive inhibitor of beta-receptor agonists and its effects on the heart can be reversed by administration of such agents: e. Atenolol should be used with caution in diabetic patients if a beta-blocking agent is required. Beta-blockers may mask tachycardia occurring with hypoglycemia, but other manifestations such as dizziness and sweating may not be significantly affected.
At recommended doses atenolol does not potentiate insulin-induced hypoglycemia and, unlike nonselective beta-blockers, does not delay recovery of blood glucose to normal levels.
Beta-adrenergic blockade may mask certain clinical signs e. Atenolol can cause fetal harm when administered to a pregnant woman. Atenolol crosses the placental barrier and appears in cord blood. Administration of atenolol, starting in the second trimester of pregnancy, has been associated with the birth of infants that are small for gestational age.
No studies have been performed on the use of atenolol in the first trimester and the possibility of fetal injury cannot be excluded. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur.
Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco. The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:. In addition to the use of this medicine, treatment for your high blood pressure may include weight control and changes in the types of foods you eat, especially foods high in sodium.
Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet. Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.
Remember that this medicine will not cure your high blood pressure, but it does help control it. You must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life. If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.
Do not interrupt or stop taking this medicine without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely. Some conditions may become worse when the medicine is stopped suddenly, which can be dangerous.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine.
If your dose is different, do not change it unless your doctor tells you to do so. The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
If you miss a dose of this medicine, take it as soon as possible. If you take atenolol and are considering having a baby, or if you are pregnant, talk to your doctor right away.
Atenolol is not the only medication that treats high blood pressure. Other drugs have fewer adverse effects during pregnancy and breastfeeding. Your doctor will be able to tell you if a different drug or a dose adjustment is an option for you. For women who are breastfeeding: Atenolol is absorbed into breast milk and could be passed to a child who is breastfed.
Newborns who breastfeed from mothers who take atenolol are also at risk of hypoglycemia and bradycardia. All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:. This medication has not been studied in children. It should not be used in children under the age of 18 years. There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dosage may cause levels of the drug to be higher than normal in your body.
When this drug is used after a heart attack, the dosage is highly individualized. It depends on the cause and the effects of the heart attack. Your doctor will monitor your blood pressure and how your heart is responding, and may adjust your dosage.
This drug is often started in the hospital. Atenolol is often dosed at mg per day, given once a day or in two divided doses. The dosage is gradually adjusted if needed. For seniors: Seniors may need a smaller dosage of atenolol at first because they can be more sensitive to the way medications act in their body. Also, as people age, they sometimes have a harder time clearing drugs from their body. After a low initial dosage, their dosage may then increase gradually.
For people with kidney disease: Kidney disease can make it more difficult for you to clear this drug from your body. Having kidney disease may affect your dosage.
Talk to your doctor about the best dosage for you. However, because drugs affect each person differently, we can not guarantee that this list includes all possible dosages. Always speak with your doctor or pharmacist about dosages that are right for you. Atenolol oral tablet is used for long-term treatment. If you stop taking it suddenly: If you suddenly stop taking atenolol for high blood pressure, chest pain, or after a heart attack, you raise your risk of heart attack.
Your blood pressure might fluctuate too often. That might increase your risk for a heart attack. If you miss a dose: If you miss a dose, just take the next dose as planned. How to tell if the drug is working: You can tell that atenolol is working if it lowers your blood pressure.
Because atenolol can lower blood pressure, your doctor may ask that you periodically check your blood pressure while taking it. Let your doctor know if you experience blood pressure readings that are either too high or too low while taking atenolol.
A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription. There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives. Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date.
However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained here in is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects.
The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses. When heart pain, or discomfort near the heart that's perceived as heart pain, strikes, you want it to go away fast.
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