Atenolol (5 brand names, 2 dosage forms, 2 routes)
Available dosage forms: TABLET, INJECTABLE.
Routes of administration: ORAL, INJECTION.
Brand Names
- ATENOLOL
- ATENOLOL AND CHLORTHALIDONE
- TENORETIC 100
- TENORETIC 50
- TENORMIN
Boxed Warning
Cessation of Therapy with Atenolol 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. Because coronary artery disease is common and may be unrecognized, it may be prudent not to discontinue atenolol therapy abruptly even in patients treated only for hypertension. (See Dosage and administration).
Indications and Usage
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. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program’s Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). 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 wi
Dosage and Administration
Hypertension The initial dose of atenolol is 50 mg given as one tablet a day either alone or added to diuretic therapy. The full effect of this dose will usually be seen within one to two weeks. If an optimal response is not achieved, the dosage should be increased to atenolol 100 mg given as one tablet a day. Increasing the dosage beyond 100 mg a day is unlikely to produce any further benefit. Atenolol may be used alone or concomitantly with other antihypertensive agents including thiazide-type diuretics, hydralazine, prazosin, and alpha-methyldopa. Angina Pectoris The initial dose of atenolol is 50 mg given as one tablet a day. If an optimal response is not achieved within one week, the dosage should be increased to atenolol 100 mg given as one tablet 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. Acute Myocardial Infarction In patients with definite or suspected acute myocardial infarction, treatment with atenolol I.V. Injection should be initiated as soon as possible after the patient’s arrival in the hospital and after eligibility is established. Such treatment should be initiated in a coronary care or similar unit immediately after the patient’s hemodynamic condition has stabilized. Treatment should begin with the intravenous administration of 5 mg atenolol over 5 minutes followed by another 5 mg intravenous injection 10 minutes later. Atenolol I.V. Injection should be administered under carefully controlled conditions including monitoring of blood pressure, heart rate, and electrocardiogram. Dilutions of atenolol I.V. Injection in Dextrose Injection USP, Sodium Chloride I
Contraindications
Atenolol is contraindicated in sinus bradycardia, heart block greater than first degree, cardiogenic shock, and overt cardiac failure (see WARNINGS). Atenolol is contraindicated in those patients with a history of hypersensitivity to the atenolol or any of the drug product’s components
Adverse Reactions
Most adverse effects have been mild and transient. The frequency estimates in the following table were derived from controlled studies in hypertensive patients in which adverse reactions were either volunteered by the patient (U.S. studies) or elicited, e.g., by checklist (foreign studies). The reported frequency of elicited adverse effects was higher for both atenolol and placebo-treated patients than when these reactions were volunteered. Where frequency of adverse effects of atenolol and placebo is similar, causal relationship to atenolol is uncertain. Volunteered (US Studies) Total-Volunteered and Elicited (Foreign + U.S. Studies) Atenolol (n = 164) % Placebo (n = 206) % Atenolol (n = 339) % Placebo (n = 407) % CARDIOVASCULAR Bradycardia 3 0 3 0 Cold Extremities 0 0.5 12 5 Postural Hypotension 2 1 4 5 Leg Pain 0 0.5 3 1 CENTRAL NERVOUS SYSTEM/ NEUROMUSCULAR Dizziness 4 1 13 6 Vertigo 2 0.5 2 0.2 Lightheadedness 1 0 3 0.7 Tiredness 0.6 0.5 26 13 Fatigue 3 1 6 5 Lethargy 1 0 3 0.7 Drowsiness 0.6 0 2 0.5 Depression 0.6 0.5 12 9 Dreaming 0 0 3 1 GASTROINTESTINAL Diarrhea 2 0 3 2 Nausea 4 1 3 1 RESPIRATORY (see WARNINGS) Wheeziness 0 0 3 3 Dyspnea 0.6 1 6 4 Acute Myocardial Infarction In a series of investigations in the treatment of acute myocardial infarction, bradycardia and hypotension occurred more commonly, as expected for any beta-blocker, in atenolol-treated patients than in control patients. However, these usually responded to atropine and/or to withholding further dosage of atenolol. The incidence of heart failure was not increased by atenolol. Inotropic agents were infrequently used. The reported frequency of these and other events occurring during these investigations is given in the following table. In a study of 477 patients, the following adverse events were reported during either intravenous and/or oral atenolol administration: Conventional Therapy Plus Atenolol (n = 244) Conventional Therapy Alone (n = 233) Bradycardia 43 (18%) 24 (10%) Hypotension 6
Overdosage
Overdosage with atenolol has been reported with patients surviving acute doses as high as 5 g. One death was reported in a man who may have taken as much as 10 g acutely. The predominant symptoms reported following atenolol overdose are lethargy, disorder of respiratory drive, wheezing, sinus pause and bradycardia. Additionally, common effects associated with overdosage of any beta-adrenergic blocking agent and which might also be expected in atenolol overdose are congestive heart failure, hypotension, bronchospasm and/or hypoglycemia. Treatment of overdose should be directed to the removal of any unabsorbed drug by induced emesis, gastric lavage, or administration of activated charcoal. Atenolol can be removed from the general circulation by hemodialysis. Other treatment modalities should be employed at the physician’s discretion and may include: BRADYCARDIA: Atropine intravenously. If there is no response to vagal blockade, give isoproterenol cautiously. In refractory cases, a transvenous cardiac pacemaker may be indicated. HEART BLOCK (SECOND OR THIRD DEGREE): Isoproterenol or transvenous cardiac pacemaker. CARDIAC FAILURE: Digitalize the patient and administer a diuretic. Glucagon has been reported to be useful. HYPOTENSION: Vasopressors such as dopamine or norepinephrine (levarterenol). Monitor blood pressure continuously. BRONCHOSPASM: A beta2 stimulant such as isoproterenol or terbutaline and/or aminophylline. HYPOGLYCEMIA: Intravenous glucose. Based on the severity of symptoms, management may require intensive support care and facilities for applying cardiac and respiratory support.