In addition, a variety of adverse effects have been reported with other beta-adrenergic blocking agents, and may be considered potential adverse effects of atenolol tablets.
Allergic: Fever, combined with aching and sore throat, laryngospasm, and respiratory distress.
Central Nervous System: Reversible mental depression progressing to catatonia; an acute reversible syndrome characterized by disorientation of time and place; short-term memory loss; emotional lability with slightly clouded sensorium; and, decreased performance on neuropsychometrics.
Gastrointestinal: Mesenteric arterial thrombosis, ischemic colitis.
Other: Erythematous rash.
Miscellaneous: There have been reports of skin rashes and/or dry eyes associated with the use of beta-adrenergic blocking drugs. The reported incidence is small, and in most cases, the symptoms have cleared when treatment was withdrawn. Discontinuance of the drug should be considered if any such reaction is not otherwise explicable. Patients should be closely monitored following cessation of therapy. (See DOSAGE AND ADMINISTRATION.)
The oculomucocutaneous syndrome associated with the beta blocker practolol has not been reported with atenolol tablets. Furthermore, a number of patients who had previously demonstrated established practolol reactions were transferred to atenolol tablets therapy with subsequent resolution or quiescence of the reaction.
Overdosage with atenolol tablets 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 tablets 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 tablets 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 tablets 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 beta 2 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.
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 tablets may be used alone or concomitantly with other antihypertensive agents including thiazide-type diuretics, hydralazine, prazosin, and alpha-methyldopa.
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.
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 Injection USP, or Sodium Chloride and Dextrose Injection may be used. These admixtures are stable for 48 hours if they are not used immediately.
In patients who tolerate the full intravenous dose (10 mg), atenolol tablets 50 mg should be initiated 10 minutes after the last intravenous dose followed by another 50 mg oral dose 12 hours later. Thereafter, atenolol tablets can be given orally either 100 mg once daily or 50 mg twice a day for a further 6-9 days or until discharge from the hospital. If bradycardia or hypotension requiring treatment or any other untoward effects occur, atenolol tablets should be discontinued. (See full prescribing information prior to initiating therapy with atenolol tablets.)
Data from other beta blocker trials suggest that if there is any question concerning the use of I.V. beta blocker or clinical estimate that there is a contraindication, the I.V. 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 seven days (if the I.V. dosing is excluded).
Although the demonstration of efficacy of atenolol tablets are based entirely on data from the first seven postinfarction days, data from other beta blocker trials suggest that treatment with beta blockers that are effective in the postinfarction setting may be continued for one to three years if there are no contraindications.
Atenolol tablets are an additional treatment to standard coronary care unit therapy.
Atenolol tablets are excreted by the kidneys; consequently dosage should be adjusted in cases of severe impairment of renal function. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Evaluation of patients with hypertension or myocardial infarction should always include assessment of renal function. Atenolol excretion would be expected to decrease with advancing age.
No significant accumulation of atenolol tablets occur until creatinine clearance falls below 35 mL/min/1.73 m 2. Accumulation of atenolol and prolongation of its half-life were studied in subjects with creatinine clearance between 5 and 105 mL/min. Peak plasma levels were significantly increased in subjects with creatinine clearances below 30 mL/min.
The following maximum oral dosages are recommended for elderly, renally-impaired patients and for patients with renal impairment due to other causes:
Creatinine Clearance (mL/min/1.73m 2)
Elimination Half-Life (h)
50 mg daily
25 mg daily
Some renally-impaired or elderly patients being treated for hypertension may require a lower starting dose of atenolol tablets: 25 mg given as one tablet a day. If this 25 mg dose is used, assessment of efficacy must 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 elderly and/or renally-impaired patients being treated for indications other than hypertension, data are not available for these patient populations.
Patients on hemodialysis should be given 25 mg or 50 mg after each dialysis; this should be done under hospital supervision as marked falls in blood pressure can occur.
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