Sunday, May 2, 2010

Atenolol,Atenolol Dosage

Generic Name: atenolol (ah TEN oh lol)
Brand Names: Tenormin

What is atenolol?

Atenolol (Tenormin) is in a group of drugs called beta-blockers. Beta-blockers affect the heart and circulation (blood flow through arteries and veins).

Atenolol is used to treat angina (chest pain) and hypertension (high blood pressure). It is also used to treat or prevent heart attack.

Atenolol may also be used for purposes other than those listed in this medication guide.

Important information about atenolol

Do not stop taking atenolol without first talking to your doctor. Stopping suddenly may make your condition worse.

If you need to have any type of surgery, you may need to temporarily stop using atenolol. Be sure the surgeon knows ahead of time that you are using atenolol.

Atenolol can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Avoid drinking alcohol, which could increase drowsiness and dizziness while you are taking atenolol.

Atenolol is only part of a complete program of treatment for hypertension that may also include diet, exercise, and weight control. Follow your diet, medication, and exercise routines very closely if you are being treated for hypertension.

If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

Store atenolol at room temperature away from moisture and heat.

What should I discuss with my healthcare provider before taking atenolol?

You should not use this medication if you are allergic to atenolol, or if you have certain heart conditions such as slow heartbeats, or heart block.

Before taking atenolol, tell your doctor if you have:

  • asthma, bronchitis, emphysema;

  • diabetes;

  • low blood pressure;

  • a heart problem such as heart block, sick sinus syndrome, slow heart rate, or congestive heart failure;

  • depression;

  • liver or kidney disease;

  • a thyroid disorder;

  • myasthenia gravis;

  • pheochromocytoma; or

  • problems with circulation (such as Raynaud's syndrome).

If you have any of these conditions, you may need a dose adjustment or special tests to safely take this medication.

FDA pregnancy category D. This medication can cause harm to an unborn baby. Do not use atenolol if you are pregnant. Tell your doctor if you become pregnant during treatment. Use an effective form of birth control while you are using this medication. Atenolol can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take atenolol?

Take atenolol exactly as it was prescribed for you. Do not take the medication in larger amounts or for longer than recommended by your doctor. Follow the directions on your prescription label.

Take this medication with a full glass of water.

Take atenolol at the same time every day.

Do not skip doses or stop taking atenolol without first talking to your doctor. Stopping suddenly may make your condition worse.

To be sure this medication is helping your condition, your blood pressure will need to be checked on a regular basis. Do not miss any visits to your doctor.

If you need to have any type of surgery, tell the surgeon that you are using atenolol. You may need to briefly stop using atenolol before having surgery.

Atenolol is only part of a complete program of treatment for hypertension that may also include diet, exercise, and weight control. Follow your diet, medication, and exercise routines very closely if you are being treated for hypertension.

If you are being treated for high blood pressure, keep using atenolol even if you feel fine. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

Store atenolol at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. If your next dose is less than 8 hours away, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include uneven heartbeats, shortness of breath, bluish-colored fingernails, dizziness, weakness, fainting, or seizure (convulsions).

What should I avoid while taking atenolol?

Atenolol can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Avoid drinking alcohol, which could increase drowsiness and dizziness while you are taking atenolol.

Atenolol side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:

  • 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, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

  • depression; or

  • cold feeling in your hands and feet.

Less serious atenolol side effects may include:

  • decreased sex drive, impotence, or difficulty having an orgasm;

  • sleep problems (insomnia);

  • tired feeling; or

  • anxiety, nervousness.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What other drugs will affect atenolol?

Before taking atenolol, tell your doctor if you are using:

  • allergy treatments (or if you are undergoing allergy skin-testing);

  • amiodarone (Cordarone, Pacerone);

  • clonidine (Catapres);

  • digoxin (digitalis, Lanoxin);

  • disopyramide (Norpace);

  • guanabenz (Wytensin);

  • an MAO inhibitor such as isocarboxazid (Marplan), tranylcypromine (Parnate), phenelzine (Nardil), or selegiline (Eldepryl, Emsam);

  • a diabetes medication such as insulin, glyburide (Diabeta, Micronase, Glynase), glipizide (Glucotrol), chlorpropamide (Diabinese), or metformin (Glucophage);

  • a heart medication such as nifedipine (Procardia, Adalat), reserpine (Serpasil), verapamil (Calan, Verelan, Isoptin), diltiazem (Cartia, Cardizem);

  • medicine for asthma or other breathing disorders, such as albuterol (Ventolin, Proventil), bitolterol (Tornalate), metaproterenol (Alupent), pirbuterol (Maxair), terbutaline (Brethaire, Brethine, Bricanyl), and theophylline (Theo-Dur, Theolair); or

  • cold medicines, stimulant medicines, or diet pills.

If you are using any of these drugs, you may not be able to take atenolol, or you may need dosage adjustments or special tests during treatment.

There may be other drugs not listed that can affect atenolol. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Where can I get more information?

  • Your pharmacist can provide more information about atenolol.

What does my medication look like?

Atenolol is available with a prescription under the brand name Tenormin. Other brand or generic forms may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you.

  • Tenormin 25 mg - round, flat, white, uncoated

  • Tenormin 50 mg - round, flat, white, uncoated

  • Tenormin 100 mg - round, flat, white, uncoated

  • Every effort has been made to ensure that the information provided is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects.

Atenolol Pregnancy and Breastfeeding Warnings

overview
Atenolol has been shown to cause harm to the fetus. If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Atenolol while you are pregnant. Atenolol is found in breast milk. If you are or will be breast-feeding while you use Atenolol , check with your doctor. Discuss any possible risks to your baby
.

Atenolol Pregnancy Warnings

Atenolol crosses the placental barrier and appears in cord blood. Administration of atenolol in the second trimester of pregnancy has been associated with the birth of infants that are small for their gestational age. In addition, some data have shown a significantly decreased fetal heart rate and significantly decreased mean birth weight of infants whose mothers were taking atenolol relative to those taking acebutolol or pindolol. Case reports of profound beta-blockade in neonates of mothers who were taking atenolol are reported. Because of this, observation of affected neonates for bradycardia and hypotension is recommended for 48 hours postpartum. The results of one study indicate that maternal renal function, mean cardiac output, and heart rate are significantly increased, while mean total peripheral resistance is significantly decreased during the second and third trimesters as compared to 3 months postpartum.

Atenolol has been assigned to pregnancy category D by the FDA. Animal studies have revealed evidence of dose-related embryotoxicity and fetotoxicity. Atenolol has been used during human pregnancy (starting in the second trimester) with evidence of lower birth weight and preterm (less than 37 weeks) delivery. Neonates born to mothers who are receiving atenolol at parturition may be at risk for hypoglycemia and bradycardia. Atenolol should only be given during pregnancy when there are no alternatives and benefit outweighs risk.

Atenolol Breastfeeding Warnings

Atenolol is excreted into human breast milk at a ratio of 1.5 to 6.8 when compared to the concentration in plasma. Neonates born to mothers who are receiving atenolol and are breast-feeding may be at risk for hypoglycemia and bradycardia. The manufacturer recommends that caution be used when administering atenolol to nursing women.

Milk atenolol levels may be four times higher than maternal serum levels. One case of bradycardia, peripheral cyanosis, and hypothermia is reported in a nursing infant whose mother was taking atenolol 50 mg orally every 12 hours. The authors calculated that the atenolol exposure to the nursing infant was 9% of the mother's daily dose. Because of this, observation of nursing infants for bradycardia and hypotension is recommended during breast-feeding. In addition, neonates born to mothers who are breast-feeding may be at an increase risk for hypoglycemia. Premature infants or infants with impaired renal function may be more at risk to develop side effects.

Atenolol Dosage

Usual Adult Dose for Hypertension

Initial dose: 50 mg orally once a day. The full effect of this dose will usually be seen within 1 to 2 weeks. If an optimal response is not achieved, the dosage should be increased to 100 mg orally once a day.

Usual Adult Dose for Angina Pectoris Prophylaxis

Initial dose: 50 mg orally once a day. If an optimal response is not achieved within one week, the dosage should be increased to 100 mg orally once a day. Some patients may require a dosage of 200 mg once a day for optimal effect.

Twenty-four hour control with once daily dosing is achieved by giving doses larger than necessary to achieve an immediate maximum effect. The maximum early effect on exercise tolerance occurs with doses of 50 to 100 mg, but at these doses the effect at 24 hours is attenuated, averaging about 50% to 75% of that observed with once a day oral doses of 200 mg.

Usual Adult Dose for Angina Pectoris

Initial dose: 50 mg orally once a day. If an optimal response is not achieved within one week, the dosage should be increased to 100 mg orally once a day. Some patients may require a dosage of 200 mg once a day for optimal effect.

Twenty-four hour control with once daily dosing is achieved by giving doses larger than necessary to achieve an immediate maximum effect. The maximum early effect on exercise tolerance occurs with doses of 50 to 100 mg, but at these doses the effect at 24 hours is attenuated, averaging about 50% to 75% of that observed with once a day oral doses of 200 mg.

Usual Adult Dose for Myocardial Infarction

IV: 5 mg over 5 minutes followed by another 5 mg injection 10 minutes later.
Oral: In patients who tolerate the full IV dose (10 mg), atenolol tablets 50 mg should be initiated 10 minutes after the last IV dose followed by another 50 mg dose 12 hours later. Thereafter, either 100 mg once a day or 50 mg twice a day for 6 to 9 days.

Usual Adult Dose for Anxiety

Initial dose: 50 mg orally once a day.
Maintenance dose: In most cases data have shown no benefit and an increased risk of fatigue with daily doses greater than 100 mg.

Usual Adult Dose for Esophageal Variceal Hemorrhage Prophylaxis

Initial dose: 50 mg orally once a day.
Maintenance dose: In most cases data have shown no benefit and an increased risk of fatigue with daily doses greater than 100 mg.

Usual Adult Dose for Migraine Prophylaxis

Initial dose: 50 mg orally once a day.
Maintenance dose: In most cases data have shown no benefit and an increased risk of fatigue with daily doses greater than 100 mg.

Usual Adult Dose for Alcohol Withdrawal

Initial dose: 50 mg orally once a day.
Maintenance dose: Initial oral doses may be titrated upward as needed and tolerated approximately every 7 days. The maximum recommended daily dose is 200 mg.

Usual Adult Dose for Supraventricular Tachycardia

Initial dose: 50 mg orally once a day.
Maintenance dose: Initial oral doses may be titrated upward as needed and tolerated approximately every 7 days. The maximum recommended daily dose is 200 mg.

Usual Adult Dose for Ventricular Tachycardia

Initial dose: 50 mg orally once a day.
Maintenance dose: Initial oral doses may be titrated upward as needed and tolerated approximately every 7 days. The maximum recommended daily dose is 200 mg.

Renal Dose Adjustments

CrCl less than 15 mL/min: Maximum dose: 25 mg orally once a day.

CrCl 15 to 35 mL/min: Maximum dose: 50 mg orally once a day.

Liver Dose Adjustments

Data not available

Dose Adjustments

Data from other beta blocker trials suggest that if there is any question concerning the use of IV beta blocker or clinical estimate that there is a contraindication, the IV beta blocker may be eliminated and patients fulfilling the safety criteria may be given atenolol tablets 50 mg twice daily or 100 mg once a day for at least 7 days (if the IV dosing is excluded).

During the second and third trimesters of pregnancy a dose adjustment may be required in order to maintain an adequate therapeutic effect because of a significant increase in atenolol renal clearance and a shorter half-life. A generalized dosage recommendation for pregnancy is not possible due to the variability in bioavailability.

Renally impaired or elderly patients being treated for hypertension may require a lower starting dose of atenolol, usually 25 mg once daily. If this lower dose is used, assessment of efficacy should be made carefully. This should include measurement of blood pressure just prior to the next dose ("trough" blood pressure) to ensure that the treatment effect is present for a full 24 hours. Although a similar dosage reduction may be considered for renally impaired or elderly patients being treated for indications other than hypertension, data are not available for these patient populations.

Precautions

Patients with coronary artery disease receiving atenolol should be advised to avoid abrupt discontinuation of the drug, as severe exacerbation of angina and occurrence of myocardial infarction and ventricular arrhythmias have occurred. 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 monitored and advised to limit physical activity to a minimum. If the angina worsens or acute coronary insufficiency develops, it is advised that atenolol be promptly reinstituted, at least temporarily. Because coronary artery disease is common and may be unrecognized, it may be prudent not to discontinue atenolol treatment abruptly even in patients treated only for hypertension.

Atenolol is contraindicated in patients with sinus bradycardia, second- or third-degree atrioventricular heart block, cardiogenic shock, untreated pheochromocytoma, and overt congestive heart failure.

Atenolol should be used with caution in patients with heart failure, a history of heart failure, bronchospastic disease, diabetes and hypoglycemia.

Beta-adrenergic blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Abrupt discontinuation of beta-blockade might precipitate a thyroid storm; therefore, patients suspected of developing thyrotoxicosis from whom atenolol treatment is to be withdrawn should be closely monitored.

Withdrawal of beta-blocker therapy prior to major surgery is controversial, as the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures.

Atenolol therapy may aggravate peripheral arterial circulatory disorders.

Atenolol therapy should be used with caution in patients with impaired renal function.

If bradycardia or hypotension requiring treatment or any other untoward effects occur, atenolol should be discontinued.

Safety and effectiveness in pediatric patients have not been established.

Dialysis

Atenolol is moderately hemodialyzable (20% to 50%). Patients should be given 25 to 50 mg after each hemodialysis.

Elimination is not enhanced via peritoneal dialysis. A supplemental dose is not needed with peritoneal dialysis.

Other Comments

Increasing the dosage beyond 100 mg a day is unlikely to produce any further benefit when treating hypertension.

Atenolol may be used alone or concomitantly with other antihypertensive agents including thiazide-type diuretics, hydralazine, prazosin, and alpha-methyldopa.

Compared with Caucasian patients, Black patients have a reduced blood pressure response to monotherapy with beta-blockers; however, the reduced response is largely eliminated if combination therapy that includes an adequate dose of a diuretic is instituted.

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